HEP Phenomenology·hep-ph

Tue·Jul 7, 2026Tuesday·July 7, 2026

70 papers—49 primary·21 cross-listed

01
Interpreting Parton Distributions with Shapley Values
Raphaël Bonnet-Guerrini🇮🇹 · Stefano Carrazza🇮🇹 · Stefano Forte🇮🇹 · Eva Groenendijk🇮🇹 · Vincenzo Piuri🇮🇹 · Ramon Winterhalder🇮🇹
We show that Shapley values can be used to trace how individual parton distributions (PDFs) shape the theory predictions for high-energy observables computed from them. This provides a tool for assessing the impact of data on PDFs when determining them, and the impact of PDF uncertainties when using the PDFs to compute collider observables. The Shapley value is computed by treating the regression of PDFs from data as a cooperative game. The PDFs are the players, and the reward is the likelihood ( $χ^{2}$ ) that characterizes the agreement between data and the predictions obtained from a given PDF, with theory and methodology held fixed. The method is agnostic to the way PDFs have been determined in the first place: for PDFs determined with a black-box AI model it may be used in order to explain the behavior of the model, and for PDFs determined using a fixed parametrization it may be used in order to expose the features and potential limitations of the parametrization. We find that the method recovers known expectations about which data constrain which PDFs in a global fit, while placing them on a more quantitative footing. We demonstrate its effectiveness in two ways. We uncover an unexpected loss of sensitivity of the gluon PDF at intermediate $x$ , with potential implications for BSM searches and the gluon fusion Higgs cross section. We also show that the method can be used to improve the hyperparameter optimization procedure currently used by the NNPDF collaboration.
hep-phhep-ex0 citations
02
EFT Validity and Truncation Uncertainty from few Nuisance Parameters
Benoît Assi🇺🇸 · Adam Martin🇺🇸 · William Shepherd🇺🇸
An observable in an Effective Field Theory (EFT) is an expansion in a set of small parameters, no different than any other perturbation series. Truncating such a series expansion leaves the leading dropped term as the dominant source of error, and that term itself contains a calculable portion. We explore the partial calculation of this next-order error, available at dim-6 $^{2}$ in SMEFT with no additional tools needed to simulate it, and explore how to efficiently use that partial calculation to model the next-order uncertainty in full using a minimal number of nuisance parameters. This estimate of the uncertainty of the EFT signal rate naturally imposes EFT validity by ensuring that bounds are driven by kinematic regions where truncation uncertainties are parametrically smaller than the signal. We incorporate the calculable dim-6 $^{2}$ piece into the signal and cover the remaining higher-dimension uncertainty with a small set of nuisance parameters derived from a scan over Wilson-coefficient values. Our algorithm to determine the relevant nuisance parameters and distributions is automation-friendly and applies to arbitrary truncation choices. We then provide multiple examples of its implementation in high-energy collider processes focused on SMEFT truncated at $O (Λ^{- 2})$ , where the dim-6 $^{2}$ piece is used to estimate the full $O (Λ^{- 4})$ dependence. In the examples considered here the reduction of nuisance parameters is appreciable, generically reducing the nuisance parameter count by an order of magnitude compared to naïve estimates.
hep-phhep-exhep-th1 citation
03
Muon lifetime and Fermi constant: an update
Alexander Eberhart🇬🇧 · Matteo Fael🇮🇹 · Alexander Keshavarzi🇬🇧 · Daisuke Nomura🇯🇵 · Kay Schönwald🇨🇭 · Matthias Steinhauser🇩🇪 · Thomas Teubner🇬🇧 · Aidan Wright🇬🇧
We present an updated prediction for the lifetime of the muon including a detailed analysis of all relevant uncertainties. Our prediction includes QED corrections up to order $α^{3}$ and state-of-the-art hadronic contributions based on dispersive methods. Radiative corrections and finite-electron-mass effects are parametrized by the correction factor $Δ q$ in $τ_{μ}^{- 1} = G_{F}^{2} m_{μ}^{5} (1 + Δ q) / (192 π^{3})$ , for which we obtain $Δ q = (- 4384678 \pm 34) \times 1 0^{- 9}$ . This reduces the uncertainty associated with $Δ q$ by an order of magnitude compared to the previous prediction at order $α^{2}$ . We use our results to provide an updated value of the Fermi coupling constant, $G_{F} = 1.166 37859 (59) \times 1 0^{- 5} GeV^{- 2}$ . Further improvements will require better measurements of the muon lifetime and mass.
hep-ph1 citation
04
Dark Matter in the General 2HDM with Extra Top Yukawa Couplings
Leon M.G. de la Vega🇹🇼 · Mohamed Krab🇹🇼
We extend the general two Higgs doublet model (G2HDM), which introduces extra Yukawa couplings, by an additional real scalar singlet (G2HDM+S), providing a viable scalar dark matter (DM) candidate. This setup provide a viable UV completion of top-window dark matter scenarios, in which DM communicates with the standard model predominantly through the top quark. We analyze the constraints on the visible scalar sector from Higgs signal strength measurements and direct searches for additional Higgs bosons at the LHC, and those on the dark sector from cosmological observables, including the observed DM relic density and spin-independent direct-detection as well as indirect detection. Within the surviving parameter space, we identify a rich and diverse LHC phenomenology governed by the interplay between the singlet portal, the extended Yukawa sector, and the heavy scalar mass hierarchy. To facilitate experimental investigation, we propose six benchmark scenarios spanning the singlet-portal, bosonic-cascade, fermiophilic, and flavor-violating regimes. In the latter, the nondiagonal top-charm coupling $ρ_{t c}$ induces the production channel $c g \to t H$ , allowing the top quark to serve as a trigger for an otherwise invisible $H \to S S$ signal. This flavor-violating DM production is a distinct feature of the G2HDM+S.
hep-phhep-ex1 citation
05
Studying baryon number transport dynamics via hyperon-kaon correlations in $p + Au$ collisions at $s_{_{NN}} = 20$ , $39$ and $62$ GeV
Siyuan Ping🇨🇳 · Xiaozhou Yu🇨🇳 · Long Ma🇨🇳
The observation of positive net hyperon baryon numbers at mid-rapidity in heavy-ion collisions indicates that baryon numbers from incident nucleons can be transported across a large rapidity gap to hyperons where strange quarks of $s - s ˉ$ are pair-produced. Consequently, hyperons and kaons are expected to be correlated, providing a sensitive probe of both baryon number transport mechanism and strange quark pair correlation. Such correlation may be used to test the gluon-junction interaction mechanism where a $Y$ -shaped gluonic field may carry the baryon number and be responsible for the baryon number transport to hyperons over a large rapidity gap. We present hyperon-kaon correlations as a function of their relative rapidity in $p + Au$ collisions at $s_{N N} = 20$ , $39$ , and $62$ GeV using a multiphase transport ( $AMPT$ ) model and Ultra-relativistic Quantum Molecular Dynamics ( $UrQMD$ ) models where hyperon-kaon pairs are originated from fragmentation scheme. We quantify the correlation function using the Wasserstein distance method and systematically investigate the correlation dependence on the beam energy, hyperon emission direction and detector acceptance. Our simulation results provide a baseline without the baryon junction mechanism for future experimental measurements.
hep-phhep-exnucl-exnucl-th0 citations
06
Revisiting $B ˉ^{0} \to Λ_{c}^{+} p ˉ$ decay with higher twist corrections
Zhou Rui🇨🇳 · Zhi-Tian Zou🇨🇳 · Ying Li🇨🇳
We investigate the single-charmed baryonic decays $B ˉ^{0} \to Λ_{c}^{+} p ˉ$ and $B ˉ^{0} \to Λ ˉ_{c}^{-} p$ , which receive contributions from both $W$ -emission and $W$ -exchange topologies, within the framework of perturbative QCD (PQCD). Higher-power corrections associated with the hadronic light-cone distribution amplitudes (LCDAs) of both the initial- and final-state hadrons are systematically taken into account. We find that these higher-twist contributions play an important role in baryonic $B$ decays and cannot be neglected. A sizable destructive interference between the $W$ -emission and $W$ -exchange amplitudes is observed, which significantly reduces the predicted branching fraction of $B ˉ^{0} \to Λ_{c}^{+} p ˉ$ and leads to improved agreement with experimental measurements. The doubly Cabibbo-suppressed decay $B ˉ^{0} \to Λ ˉ_{c}^{-} p$ is studied for the first time. Its branching fraction is predicted to be of order $1 0^{- 8}$ , placing it within the reach of future high-luminosity experiments. We further present the first theoretical predictions for the decay asymmetry parameters of both channels, which provide additional observables for testing the underlying decay dynamics and can be confronted with future experimental data.
hep-phhep-ex0 citations
07
Majoron Dark Energy via Freezing Induced by Quantum Coherence
Keunsu Cheon · Sin Kyu Kang🇰🇷 · Jungjai Lee🇨🇳
We propose a nonequilibrium mechanism for Majoron dark energy in which the late-time freezing of a physical Majoron is induced by quantum coherence in a hidden pseudo-Dirac sterile fermion reservoir. The evolving Majoron background derivatively couples to the hidden pseudo-Dirac number current and drives a lagged reservoir response with a finite memory time. In the short-memory regime, the causal response kernel reduces to $\dot X+\Gamma_{\rm PD}X=\beta\ddot\phi$. The leading linear-response matching $Q=\alpha X$ then yields an effective scalar equation containing the exchange structure $q_{\rm exch}\ddot\phi/\dot\phi$. We show that this term can dynamically suppress the Majoron velocity and sustain a response-dominated freezing branch even when the intrinsic Majoron mass is larger than the present Hubble scale. The microscopic origin of the lag variable is identified with the phase-lagged off-diagonal coherence of the hidden pseudo-Dirac ensemble, while the response strength is controlled by a response-weighted hidden density rather than by an independent gravitating component. The resulting state is a metastable nonequilibrium frozen phase with $w_\phi\simeq -1$, rather than an exactly static cosmological constant.
hep-phastro-ph.COgr-qchep-th0 citations
08
Flipped rotating axion: Baryogenesis and Dark Matter
Konstantinos Dimopoulos🇬🇧
It is shown that the co-genesis of baryon asymmetry and dark matter can be achieved through the rotation of a spectator axion-like particle, because of a flip in the vacuum manifold's orientation at the end of inflation. This can occur if the axion has a periodic non-minimal coupling to gravity (while preserving the discrete shift symmetry) in non-oscillating inflation models, where the inflaton field is characterised by a runaway potential. Our rotating axion can generate the baryon asymmetry of the Universe through spontaneous baryogenesis, while at a later epoch it can oscillate as dark matter. We show that in order to avoid fragmentation of the axion condensate during the rotation, we require the non-minimal coupling $ξ \sim (f / m_{P})^{2}$ , where $f$ is the axion decay constant.
hep-phastro-ph.COgr-qchep-thPoS(2026)·0 citations
09
George, I and the curvaton
Konstantinos Dimopoulos🇬🇧
George Lazarides was a pivotal collaborator and friend to me. We worked together on several projects, developing and exploiting the curvaton hypothesis, which was new at the time. This is a brief overview of our joint research.
hep-phastro-ph.COgr-qchep-thPoS(2026)·0 citations
10
Polarized Nucleon as a Topological Dipole
Kenji Fukushima🇯🇵 · Tomoya Uji🇯🇵
We show that a polarized nucleon generically carries a dipole distribution of topological charge density. This topological dipole follows robustly from the definition of the topological form factor and the pseudoscalar nature of the topological charge density. The strength of the topological dipole is fixed, in the chiral limit, by the flavor-singlet axial charge. We demonstrate the mechanism in a two-flavor chiral soliton model with vector mesons and the $U (1)_{A}$ anomaly, where the rotation of the soliton induces a singlet pseudoscalar profile and realizes the predicted dipole pattern. We also discuss possible experimental probes through exclusive $η$ , $η^{'}$ production and directed-flow-like pseudoscalar-meson asymmetries correlated with magnetic fields or vorticity in relativistic heavy-ion collisions.
hep-phnucl-th0 citations
11
A Unified Dark Matter Explanation for $B^{+} \to K^{+} ν ν ˉ$ and the Super-Kamiokande Antineutrino Excess
Shu-Yu Ho🇹🇼 · Jongkuk Kim🇰🇷 · Pyungwon Ko🇰🇷
Recent results from Super-Kamiokande and Belle II have revealed intriguing excesses over Standard Model expectations. Super-Kamiokande observes a mild excess of $ν ˉ_{e}$ -like events near $20 MeV$ , while Belle II reports a branching fraction for $B^{+} \to K^{+} ν ν ˉ$ that exceeds the Standard Model prediction by approximately $2.7 σ$ . In this work, we study the simplest UV-complete complex scalar dark matter model with a gauged $U (1)_{L_{μ} - L_{τ}}$ symmetry. We demonstrate that a light dark sector can simultaneously reproduce the observed dark matter relic density and accommodate both excesses within a unified framework.
hep-ph0 citations
12
Probing a 146 GeV cLFV scalar using the LHC and low-energy experiments
Christina Gao🇨🇳 · Lingfeng Li🇨🇳 · Z.J. Xiong🇨🇳
The CMS Collaboration reported a local excess at $146 GeV$ in the search for the lepton-flavor-violating decay of the Higgs boson and additional Higgs bosons in the $e μ$ final state at $s = 13 TeV$ . If confirmed, this would constitute a major piece of evidence of charged lepton flavor violation (cLFV). We investigate the compatibility of the claimed signal with the full suite of existing low-energy cLFV constraints in a bottom-up effective description: a single real scalar of mass $146 GeV$ coupled to gluons and to all charged-lepton bilinears, with seven free parameters that simultaneously control the LHC production cross section, every di-lepton decay channel, and every low-energy cLFV observable. A Bayesian MCMC analysis against $μ - e$ conversion, muonium-antimuonium oscillation, three-lepton and radiative LFV decays, semileptonic $τ$ LFV decays, and LHC di-lepton searches yields a preferred mode with peaked value $Y_{e μ} \sim 1 0^{- 4.09}$ , already cut into by the current $μ - e$ conversion limits. The projected sensitivities of Mu2e, COMET, Mu3e, MACE, MEG~II, Belle~II, STCF, and the HL-LHC directly probe the region of coupling space selected by the CMS excess, so the complementarity between high-energy and low-energy cLFV probes will either corroborate or decisively exclude the scalar interpretation of the anomaly within the next decade.
hep-phhep-th1 citation
13
First look at the evaluation of two-loop Feynman integrals for radiative return processes
Mattia Pozzoli🇮🇹 · William J. Torres Bobadilla🇬🇧
Precision studies of radiative return processes at low-energy electron--positron colliders require next-to-next-to-leading order QED predictions retaining full dependence on the electron mass. We present the calculation of planar two-loop four-point Feynman integrals relevant for initial-state radiation contributions to these processes. The calculation presents considerable analytical complexity, due to the presence of a nested square root and of integrals associated with elliptic geometries. We construct differential equations for the Feynman integrals which are polynomial in the dimensional regulator, and are suitable for numerical integration. We demonstrate stable numerical evaluations throughout the physical region relevant for low-energy experiments, despite the presence of large hierarchies of scales. Our results provide essential building blocks for NNLO predictions for radiative return processes.
hep-phhep-th1 citation
14
Analytic result of a three-loop integral family in the Higgs decay to four massive bottom quarks
Jian Wang🇨🇳 · Xing Wang🇨🇳 · Yefan Wang🇨🇳
When calculating the decay width of $H \to b b ˉ b b ˉ$ induced by the effective Higgs-gluon-gluon interaction using the optical theorem, the three-loop Feynman diagrams are encountered. Among them, there is an interesting integral family, which involves not only the sectors evaluated to multiple polylogarithms but also those related to an elliptic curve and a K3 surface. We demonstrate how to construct and solve the canonical differential equation for the entire family, which includes mixing between different sectors, by using the recently proposed algorithm in~\cite{e-collaboration:2025frv, Bree:2025tug}. Analytical results for all master integrals in this family up to the first two orders of $ε$ are given.
hep-phhep-th1 citation
15
A Dispersive Look at Rare $B$ -meson Semileptonic Decays
Marco Ciuchini🇮🇹 · Marco Fedele🇩🇪 · Ayan Paul🇺🇸 · Josua Scholze🇩🇪 · Luca Silvestrini🇮🇹 · Silvano Simula🇮🇹 · Mauro Valli🇮🇹 · Ludovico Vittorio🇮🇹
Rare semileptonic $b \to s$ flavour-changing neutral current transitions provide stringent tests of the Standard Model. Their interpretation is limited by hadronic uncertainties, notably the $B \to K^{(*)}$ and $B_{s} \to ϕ$ form factors (FFs) and the matrix elements of four-quark operators. We perform a global analysis of $b \to s ℓ^{+} ℓ^{-}$ transitions taking these uncertainties fully into account, determining the FFs through the Dispersive Matrix method and comparing a setup based solely on lattice QCD (LQCD) with one that also includes light-cone sum-rule (LCSR) inputs at low $q^{2}$ . Compared to the case where both input are taken into account, using only LQCD substantially enlarges the FF uncertainties at large recoil. Combined with the latest LHCb and CMS angular measurements sensitive to strong phases, our global fit yields strengthened evidence in favour of long-distance hadronic effects rather than a short-distance shift in $C_{9}$ . We further present new SM predictions for the theoretically clean $b \to s ν ν ˉ$ modes, which depend only on local FFs, and a New Physics analysis of these transitions in the Weak Effective Theory, discussing their impact on the interpretation of the recent Belle~II measurement and on the available experimental upper bounds.
hep-phhep-ex2 citations
16
Gravitational Wave Signatures of Cosmological Stasis: A Unified Spectral Template
Gabriela Barenboim🇪🇸 · Anne-Katherine Burns🇪🇸
Proposed in 2022 by Dienes et al., stasis is a dynamical fixed point in the early universe in which the equation of state, $w_{s}$ , is fixed at a constant value. In this study we show that the inflationary gravitational wave imprint of any stasis epoch is captured by a closed-form spectral template controlled by two physical inputs, the equation of state $w_{s}$ and the stasis duration $Δ N_{stasis}$ , that applies uniformly across every microphysical realization. The template presented here yields two independently measurable observables, the spectral tilt of the spectra in the stasis band, $α (w_{s})$ and the amplitude step $C^{2} (w_{s})$ at the beginning and end of the stasis band. Eliminating $w_{s}$ gives a one-parameter consistency curve $C^{2} = C^{2} (α)$ on which the data must lie if the underlying cosmology is any constant- $w$ era. This makes the spectrum falsifiable without knowing $w_{s}$ in advance: a measured $(α, C^{2})$ pair either lands on the curve or rules out the constant- $w$ class. We show that BBO and DECIGO can resolve the perpendicular displacement from the consistency curve to $σ_{⊥} ≃ 1.5 \times 1 0^{- 5}$ at a tensor-to-scalar ratio, $r = 0.01$ , four orders of magnitude below the curve's range in $C^{2}$ meaning that any off-curve deviation is detectable across a broad range of allowed $r$ values.
hep-phastro-ph.COgr-qc2 citations
17
Spontaneous CP breaking in $S_{3}$ flavored Higgs sector with soft-breaking terms
E. Barradas-Guevara🇲🇽 · O. Félix-Beltrán🇲🇽 · A. Pérez Martínez🇲🇽 · E. Rodríguez-Jáuregui🇲🇽 · J. Montaño-Peraza🇲🇽
We analyze the Higgs sector of the minimal $S_{3}$ -invariant extension of the Standard Model including spontaneous and explicit CP violation arising from the spontaneous electroweak symmetry breaking. This extended Higgs sector includes three SU(2) Higgs doublets with and without complex vev's, which ones providing an interesting scenario to analyze the Higgs masses spectrum, trilinear Higgs self-couplings and CP violation. We present how the spontaneous electroweak symmetry breaking coming from three SU(2) Higgs doublets gives an interesting scenario when spontaneous CP violation arises from the Higgs doublet $Φ_{S}$ , singlet under $S_{3}$ . Furthermore, a numerical analysis of the Higgs masses and trilinear Higgs self-couplings is presented. Particularly, we find a physical solution for the scenario in which spontaneous CP break is provided by $Φ_{S}$ . The analysis of soft breaking to $S_{3}$ symmetry including CP breaking terms opens up a rich parameter space, with Higgs masses and trilinear Higgs self-couplings favoring one of the Higgs bosons as a SM-like type Higgs boson.
hep-phPLB(2026)·0 citations
18
Probing Fermion-Portal Scalar Dark Matter through Charged Vector-Like Fermions at Future Muon Colliders
Songshaptak De🇸🇮 · Tapoja Jha🇫🇮 · Najimuddin Khan🇮🇳 · Madhurima Pandey🇮🇳
We revisit a minimal fermion-portal scalar dark matter model consisting of a real singlet scalar dark matter candidate and additional vector-like singlet and doublet charged fermions stabilized by a discrete $Z_{2}$ symmetry. In light of the latest dark matter direct-detection constraints, the conventional Higgs-portal interaction is severely restricted, motivating a detailed investigation of fermion-mediated dark matter annihilation channels. We perform a comprehensive analysis of the model parameter space by incorporating theoretical constraints from vacuum stability and perturbative unitarity, together with experimental bounds from relic density measurements, direct-detection experiments, Higgs invisible decay searches, lepton-flavor-violating processes, and anomalous magnetic moments. We show that the observed dark matter relic abundance can be successfully reproduced over a wide mass range through Yukawa-driven $t$ - and $u$ -annihilation and co-annihilation processes involving the new fermions, while remaining consistent with current direct-detection limits. Motivated by the viable parameter space, we investigate the discovery prospects of the lightest charged vector-like fermion at future muon colliders operating at center-of-mass energies of 3 TeV and 10 TeV. Focusing on the process $μ^{+} μ^{-} \to E_{1}^{+} E_{1}^{-} \to e^{+} e^{-} + E_{T}$ , we perform a detector-level analysis including realistic Standard Model backgrounds. We demonstrate that the clean experimental environment of a muon collider provides excellent sensitivity to charged fermion masses extending into the multi-TeV regime, significantly improving the exploration prospects of this class of fermion-portal dark matter scenarios.
hep-ph1 citation
19
Dark matter scattering with pre-supernova neutrinos
Sangeetha N. Tallur🇮🇳 · Nirmal Raj🇮🇳
Pre-supernova neutrinos, emitted during the last day prior to core collapse of a massive star, could provide a unique probe at MeV energies of scattering interactions between dark matter and neutrinos. Due to attenuation of the flux of electron anti-neutrinos from their scattering on dark matter on the way to Earth, we expect a deficit of inverse beta decay events at large-volume, low-threshold detectors such as KamLAND, JUNO, and Super-K. which we use to derive upper limits on the dark matter-neutrino reduced scattering cross section. Though seemingly weaker than limits from post-bounce supernova neutrino events, these sensitivities provide an important cross-check, could help determine the energy dependence of the cross section, and may even be a distinct probe of certain models. Further, pre-supernova neutrinos may test hints reported of dark matter-neutrino scattering in the early universe suppressing small-scale power as seen in Lyman-alpha data.
hep-ph0 citations
20
Phenomenological extraction of fragmentation functions in a $p p ˉ$ environment
M. A. Pérez de León🇲🇽 · S. A. Ochoa-Oregón🇲🇽 · D. F. Rentería-Estrada🇪🇸 · R. J. Hernández-Pinto🇲🇽
The precise determination of fragmentation functions (FFs) of hadrons relies on the accurate description of the differential cross sections obtained from both experimental high-energy hadron colliders and theoretical predictions at higher orders in quantum chromodynamics. Various phenomenological strategies have been employed to extract FFs. In this work, we analyze the use of kinematical cuts for reactions including pions and kaons in proton-antiproton collisions to isolate individual FF contributions. This study examines the feasibility of using a similar approach as in proton-proton colliders to analyze FF flavour separation~\cite{Ochoa-Oregon:2023ktx}. In particular, we study photon-hadron production at colliders, including NLO QCD and LO QED corrections to reconstruct the partonic momentum fractions.
hep-phFew Body Syst.(2026)·0 citations
21
Exclusive production of P-wave charmonia through two virtual photons in electron-positron annihilation
Avinash Okram🇮🇳 · Shashank Bhatnagar🇮🇳
We present a relativistic study of the exclusive double-charmonium processes $e^{-} e^{+} \to γ^{*} γ^{*} \to χ_{c 1} + η_{c}$ and $e^{-} e^{+} \to γ^{*} γ^{*} \to h_{c} + h_{c}$ at $s = 10.6$ GeV in the framework of the $4 \times 4$ Bethe-Salpeter equation. Since these channels are forbidden in single-photon annihilation, they proceed purely through two-photon quark-rearrangement mechanisms and thus provide a clean probe of relativistic quarkonium dynamics. Using parameters fixed from mass spectroscopy in our earlier work, we obtain leading-order predictions for the total cross sections and their energy dependence. The predicted cross sections are of order $1 0^{- 3}$ fb and exhibit a hierarchy that originates from the radial structure of the meson wave functions, which determines the overlap integrals contributing to the production amplitude. While the absolute magnitudes of the cross sections differ from NRQCD estimates, the qualitative ordering of the channels is consistent with NRQCD expectations. We find a smooth power-law falloff of the cross section for both $χ_{c 1} + η_{c}$ and $h_{c} + h_{c}$ . These results provide benchmark predictions for future searches at high-luminosity $e^{-} e^{+}$ colliders.
hep-ph0 citations
22
Probing axion in the DFSZ model
H. N. Long · N. H. T. Nha🇻🇳
We show that with the introduction of new right-handed neutrinos $N_{R}$ , the Peccei--Quinn ( $P Q$ ) transformation in the DFSZ (Dine--Fischler--Srednicki--Zhitnitsky) model depends only on the $P Q$ charge of the scalar singlet $ϕ$ , namely $P Q_{ϕ}$ , and is independent of the sine and cosine of $arctan (v_{u} / v_{d})$ . The model consists of four new scalars: a charged Higgs boson $H^{\pm}$ , a CP-odd scalar $A$ , and two CP-even scalars with masses at the EW scale (of a few hundred GeV), and a superheavy inflaton $Φ$ . The scalar fields have been presented in the form of unitary matrices, in which there is no mixing between the axion and the Goldstone boson $G_{Z}$ . As a result, there are two kinds of couplings between the axion and fermions, namely Yukawa-like interactions and anomaly-induced ones associated with derivative axion couplings. {The model belongs to the DFSZ I kind since the axion - photon coupling with $\fr E N = \fr 83$ .} The trilinear Higgs self-coupling is investigated. We have shown that, in the parameter region where new scalar fields such as the singly charged Higgs boson $H^{\pm}$ and the CP-odd scalar $A$ have masses around 150 GeV and the vacuum expectation value of one Higgs doublet ( $v_{u}$ ) is of the order of a few GeV, the coupling modifier $κ_{λ}$ -a probe of new physics-is consistent with the current experimental constraints.
hep-ph0 citations
23
Left-right symmetry breaking in $E_{6}^{L} \times E_{6}^{R}$ occurs only in spacetime -- with possible implications for strong $C P$
Tejinder P. Singh🇮🇳
Two-sided octonionic $E_{6}^{L} \times E_{6}^{R}$ unification carries a nominal second colour $S U (3)_{c^{'}}$ which, gauged, would colour the charged lepton and must be suppressed by hand. We argue no such device is needed: the left-right symmetry acts in spacetime, not internally -- in the gravi-weak reading $S U (2)_{R}$ is the gravitational frame group and the exchange is ordinary parity on the Dirac field; a spacetime operation cannot double the internal colour, so $S U (3)_{c^{'}} = S U (3)_{c}$ , one vector-like colour with a colour-singlet electron. The right sector contributes one colour-blind datum, $m$ (values: the exceptional-Jordan trace split, an input; $N_{R}$ fixes only the colour representation). An anomaly no-go proven here shows every anomaly-free $U (1)$ on visible fermions lies in span ${Q, B - L}$ , which the $m$ pattern does not, in any sign or chirality assignment. The gauged dark-electromagnetic $U (1)_{d e m}$ -- the mirror electroweak chain's unbroken remnant -- therefore carries the parity-mirror of electric charge on the dark sector: the visible fermions are dem-neutral (kinetic mixing the sole portal; no visible fifth force), and $m$ enters visible physics only as the spectral label of the Jordan mass operator. The same recognition recovers hypercharge as the consistency relation $Y = Q - T_{L}^{3}$ , $Q = N /3$ , with no right-sector generator. As an application, the spontaneous parity forbids the QCD vacuum angle ( $θ_{QC D} = 0$ , conditional on the gravi-weak identification), while the flavour rotors have real determinant, so $ar g det M = 0$ at tree level (exact for the Cabibbo rung, texture-contingent in full), coexisting with a nonzero CKM phase. Loop stability -- where minimal gauged- $S U (2)_{R}$ parity solutions fail -- is plausibly evaded (no gauged $W_{R}$ ) but open, pending the Higgs-bridge matrix elements. We tag throughout what is derived, what is input, and what is open.
hep-phhep-th2 citations
24
Naturally Light Composite Higgs as a Protected Collective Eigenmode
Gauhar Abbas🇮🇳
Standard routes to a light composite Higgs either rely on tuning a single channel near criticality or protect a pseudo-Nambu--Goldstone coordinate of a coset. We introduce a third mechanism class in which the protected object is an \emph{eigenvalue} of the renormalized multi-operator scalar kernel of the strong sector. Two basis-invariant diagnostics, a sector participation number $\Psec$ and a sector gap ratio $\Rcoll$ , identify collective lightness, but they cannot distinguish an accidental small determinant from a protected zero mode; the missing discriminator is the microscopic sensitivity $Δ_{g} = \partial ln ∣ m_{H}^{2} ∣/ \partial ln g$ . A protected collective Higgs is defined by $\Rcoll ≫ 1$ , $\Psec > 1$ , and $Δ_{g} = O (1)$ . We prove that this class is nonempty. A rank-one TC--DTC locking invariant forbids tree-level aligned curvature, while universal vectorlike DQCD bridge fermions, massless in the microscopic Lagrangian but acquiring a common DQCD constituent mass, obey $\partial_{h}^{2} \sum_{A} \Tr M_{A}^{2}_{0} = 0$ . The aligned scalar is therefore lifted only at joint two-spurion order, $m_{br}^{2} = - (d_{X} /2 π^{2}) g_{T}^{2} g_{D}^{2} (f_{B}^{4} / f_{H}^{2}) L_{X}$ , giving $Δ_{g_{T}} = Δ_{g_{D}} = 2$ at leading logarithmic order. The same DTC topology admits a collective top completion and a vector-decoupling route to reducing the positive technicolor contribution to $S$ . The mechanism is falsifiable by sector-restricted lattice spectroscopy and coupling-response scans.
hep-phhep-lat0 citations
25
A MeV-Scale Dark QCD Solution to the Axion Domain Wall Problem
Jun Guo🇨🇳 · Zhaofeng Kang🇨🇳 · Jiang Zhu🇨🇳
PQ solution to the strong CP problem probably encounters the axion domain wall problem. In this article, we propose a simple and testable solution, assuming that the $U (1)_{PQ}$ possesses mixed anomaly to a hidden $S U (N_{c})$ color. Then, the axion field receives a new cosine potential from the hidden instantons, which breaks the $Z_{N_{DW}}$ subgroup explicitly. The new potential lifts the vacua degeneracy, but also drives the effective $θ$ angle away from the origin, re-incuring the strong CP problem. However, we find that the dark QCD scale within the 0.1 to 3 MeV window survives, maintaining a delicate balance. Two observational signatures are explored: gravitational waves from domain wall collapse, already probed by current PTAs, and di-photon signals from axion-dark-glueball mixing, which require next-generation MeV telescopes. The scenario favors a cold dark QCD sector consistent with dark glueball relic constraints.
hep-ph0 citations
26
Advancing axion detection: Photon regeneration in high-sensitivity Penning trap experiments
Yao Chen · Ju Guo🇺🇸 · Libo Zhao🇨🇳 · Ziyao Yan🇨🇳 · Jie Feng🇨🇳
The axion, a hypothetical particle proposed to solve the strong CP problem and considered a viable candidate for dark matter, has prompted extensive experimental efforts for its detection. This study presents a novel approach combining photon regeneration techniques ("light-shining-through-a-wall") with high-sensitivity Penning trap technologies to enhance the search for axions. Penning traps offer significant advantages, including precise electromagnetic field measurement, strong magnetic fields, and single-particle detection capabilities. By integrating these traps with resonantly enhanced photon regeneration using microwave cavities, our proposed method significantly increases sensitivity to axion-photon couplings. Preliminary calculations demonstrate an unprecedented achievable sensitivity, reaching an axion-photon coupling constant limit of $g_{aγ γ} \leq 7.10 \times 1 0^{- 8} Ge V^{- 1}$ in just one day, specifically targeting axion energies below 1 MHz. This experimental setup presents a robust and controlled platform, circumventing astrophysical uncertainties, and represents a substantial advancement in laboratory searches for axions and our understanding of dark matter.
hep-phInt. J. Mod. Phys. A (2026) 2641004·0 citations
27
Disentangling Scheme Dependence in Quasi-PDFs with a Transverse-Momentum Cutoff
Junegone Chay🇰🇷
Quasi-PDFs provide a connection between Euclidean spatial correlations in lattice QCD and lightcone parton distributions. Their perturbative expressions contain both the infrared divergence required for matching and the scheme-dependent contributions associated with the renormalization prescriptions. The separation of these two ingredients is not always transparent. In this work we use a transverse-momentum cutoff as a simple setting in which these ingredients can be systematically decomposed into a scheme-dependent sector and a remainder for the nonsinglet quark quasi-PDF at one loop. We choose the minimal transverse-momentum-cutoff scheme, where the scheme-dependent sector is identified by its explicit cutoff dependence, while the remainder contains the full collinear infrared divergence and the finite contribution relevant for matching to the lightcone PDF. After expressing the quasi-PDF in terms of distributions, we show how to deal with the linear divergence and the logarithmic terms in the counterterm, and discuss the dependence of the renormalization-group behavior on the renormalization prescriptions. This organization clarifies how scheme dependence enters the quasi-PDF before the final matching is performed, and provides a benchmark for examining analogous separations in other renormalization schemes.
hep-phhep-lat1 citation
28
Lagrangian-based model of the $e^{+} e^{-} \to V V ˉ$ process applied to the $e^{+} e^{-} \to D^{*+} D^{*-}$ data
Peter Lichard🇨🇿
Using the quantum field theory, we derive a Breit-Wigner-type formula for the $e^{+} e^{-}$ annihilation into a vector meson and its antiparticle, and relate the formula parameters to observable quantities. The formula's soundness is checked by fitting the $e^{+} e^{-} \to D^{*+} D^{*-}$ data published by the BESIII Collaboration in 2022.
hep-phhep-ex0 citations
29
Vector meson photoproduction on the nucleus and the extraction of the nuclear suppression factor using asymmetric beams
Ronan McNulty🇮🇪 · Wolfgang Schafer🇵🇱
The cross-section for photoproduction of a vector meson on a nucleus is usually determined in nucleus-nucleus collisions, which introduces a two-fold ambiguity as to which nucleus emitted the photon. This can be resolved in asymmetric collisions of protons and nuclei, where the ratio of photoproduction cross-sections on the proton and nucleus directly measures the nuclear suppression factor with minimal model dependence. The feasibilty of using existing and future proton-lead collisions at the LHC is evaluated.
hep-ph0 citations
30
Double strange hybrid baryon
B. Barsbay🇹🇷 · K. Azizi🇮🇷 · H. Sundu🇹🇷
We investigate the spectroscopic properties of the double strange hybrid baryon with quark content $ss q g$ within the framework of QCD sum rule. Using an interpolating current with explicit gluonic degrees of freedom, the two-point correlation function is analyzed in terms of two independent Lorentz structures, $\slashed q$ and $I$ . The operator product expansion is carried out by including vacuum condensates up to dimension ten, and the corresponding sum rules are derived for both structures. By taking the average of the results obtained from the two Lorentz structures, we extract the masses and pole residues of the ground and first excited states. For the ground state, we obtain a mass of $M = (1593.44 \pm 130.29) MeV$ and a residue of $λ = (2.57 \pm 0.40) \times 1 0^{- 3} GeV^{5}$ . For the first excited state, the corresponding values are $M = (1897.47 \pm 124.44) MeV$ and $λ = (2.88 \pm 0.62) \times 1 0^{- 3} GeV^{5}$ . The obtained results provide theoretical predictions for the double strange hybrid baryon spectrum and may be useful for future experimental searches as well as further nonperturbative studies of hybrid hadrons.
hep-phhep-exhep-lat0 citations
31
Updated analysis of minimal supersymmetric SO(10) with a universal soft spectrum
Cheng-Wei Chiang🇹🇼 · Takeshi Fukuyama🇯🇵
We update the analysis of minimal supersymmetric SO(10) grand unification with a universal, constrained-MSSM-like soft-breaking spectrum. A pair of Yukawa matrices in the $10 \oplus 126$ Higgs sector fixes the charged fermion masses and quark mixing, the baryon number-violating dimension-five operators that mediate proton decay, and the right-handed neutrino Majorana masses of the type-I seesaw. The simultaneously imposed constraints include: (i) gauge coupling unification and vacuum stability; (ii) dimension-five proton decay (the dimension-six gauge mode also computed and negligible), the 125-GeV Higgs mass, and the LEP chargino limit; and (iii) $μ \to e γ$ , the muon $g - 2$ , and electric dipole moments. We perform a global scan over the soft-breaking parameters, complemented by a constrained- $μ$ cross-check that fixes the electroweakino sector from the GUT-scale boundary conditions through radiative electroweak symmetry breaking. Subject to a single effective colored-Higgs scale $M_{H_{C}}$ for the proton decay normalization and to a constrained- $μ$ treatment, what survives is a narrow mini-split region: heavy, multi-tens-of-TeV scalars with $m_{0} ≳ 7.7$ ~TeV and $tan β ≲ 9$ . We also examine the fate of the lightest supersymmetric particle as a dark matter candidate, in both the universal model and its free- $μ$ non-universal-Higgs-mass extension. The surviving region is sharply bounded and testable in the coming decade, most directly by Hyper-Kamiokande proton decay and electroweakino searches, with dark matter direct detection and electric dipole moment experiments.
hep-phhep-ex0 citations
32
Anomalous triple gauge couplings in the light of dimension-8 operators in $W^{+} W^{-}$
Daniel Gillies🇬🇧 · Andrea Banfi🇬🇧 · Adam Martin🇺🇸
We compare the size of dimension-8 effects on $W^{+} W^{-}$ production at the LHC arising from the $q q ˉ$ and $γ γ$ initial states. In particular, we consider bosonic operators, which contribute to the anomalous triple and quadruple gauge couplings. The relevant dimension-6 and dimension-8 operators are matched to the anomalous triple gauge couplings that contribute to the $q q ˉ$ channel, allowing for the resummation of large logarithmic contributions arising in the presence of a jet-veto through the program MCFM-RE. For the $γ γ$ channel, which receives contributions from both triple and quadruple gauge couplings, such resummation can be performed through the program MadGraph, by simply setting the factorisation scale to the jet-veto scale. We find that, when neglecting fermionic dimension-8 operators, the $γ γ$ channel has a dominant bosonic dimension-8 contribution and this channel can be used to understand the range of validity of the Effective Field Theory. With this in mind, and carefully considering theoretical and experimental uncertainties, we provide constraints on higher dimensional operators using current and future data.
hep-phhep-ex0 citations
33
Quantum interference effects enhanced in $π^{+} p$ femtoscopic correlation functions
Zhi-Wei Liu🇨🇳 · Jun-Xu Lu🇨🇳 · Duo-Lun Ge🇨🇳 · Li-Sheng Geng🇨🇳
We present a comprehensive analysis of the $π^{+} p$ femtoscopic correlation functions measured by the ALICE Collaboration in high-multiplicity $pp$ collisions at $s = 13$ TeV. Using the Koonin-Pratt formula with a Gaussian source and data-driven $π N$ partial-wave amplitudes, we account for the contributions from $π^{+} p$ scattering and $Δ (1232)^{++}$ -decay, thereby successfully reproducing the measured data and their transverse-mass ( $m_{T}$ ) dependence. The scattering contribution yields a peak near the relative momentum $k \approx 140$ MeV/ $c$ , whereas the decay contribution peaks around $k \approx 220$ MeV/ $c$ . The observed correlation peak results from a weighted sum of the two contributions, with $m_{T}$ -dependent relative weights. We find that the 140 MeV/ $c$ peak originates from quantum interference between the incident and scattered waves-a mechanism previously unnoticed in femtoscopic studies. This finding resolves the peak-shift puzzle in $π^{+} p$ correlations and provides a novel perspective for quantum interference effects in femtoscopy.
hep-phhep-exnucl-ex1 citation
34
Charting doubly strange hidden-charm pentaquarks: An electromagnetic mapping of spin- $\frac{1}{2}$ and $\frac{3}{2}$ states
Ulaş Özdem🇹🇷
We calculate the magnetic dipole moments of doubly strange hidden-charm pentaquark states with spin-parity $J^{P} = 1/ 2^{-}$ and $3/ 2^{-}$ using QCD light-cone sum rules (LCSR), presenting the first systematic LCSR investigation of the electromagnetic multipole structure in the $S = - 2$ sector. To assess the model dependence, we employ independent interpolating currents in diquark-diquark-antiquark form, which probe different assumptions about the internal color-spin correlations. For the spin- $3/2$ states, we also compute the electric quadrupole and magnetic octupole moments. The magnetic dipole moments exhibit a considerable spread across currents, ranging from $- 2.15 μ_{N}$ to $5.74 μ_{N}$ for spin- $1/2$ pentaquarks and from $- 4.25 μ_{N}$ to $- 0.43 μ_{N}$ for spin- $3/2$ states, reflecting the sensitivity of magnetic moments to the internal wave function. A quark-level decomposition reveals that the charm quark dominates in most configurations, while strange quarks play a decisive role only in currents favoring axial-vector diquark structures. The electric quadrupole moments lie between $- 2.01 \times 1 0^{- 2}$ fm $^{2}$ and $5.55 \times 1 0^{- 2}$ fm $^{2}$ , and the magnetic octupole moments are typically an order of magnitude smaller. The current dependence of the magnetic dipole moments provides a quantitative measure of the theoretical uncertainty arising from the choice of interpolating operator. The pronounced isospin sensitivity of $J_{μ}^{3} (x)$ across all three multipole moments arises from its axial-vector diquark structure, which isolates the light quark from spin averaging and allows the charge asymmetry $e_{u} / e_{d} = - 2$ to propagate directly into the electromagnetic moments; the ratio $μ_{u} / μ_{d} = - 2.00$ confirms this mechanism exactly. Our predictions offer benchmarks for future experiments and lattice QCD calculations, and may help discriminate among competing structural models.
hep-phhep-exhep-lathep-thChin.J.Phys.(2026)·0 citations
35
Comment on "Radiative corrections to tau -> pi(K) nu_tau[gamma]: A reliable new physics test"
Markus Finkemeier
Arroyo-Ureña, Hernández-Tomé, López-Castro, Roig, and Rosell (AHLRR) take the structure-dependent (SD) amplitude for $τ \to P ν_{τ} γ$ from the resonance chiral theory result of Guo and Roig (GR10), obtaining $δ r_{S D} = + 0.15%$ in the pion channel. The convention dictionary in footnote 2 of GR10, repeated in footnote 1 of AHLRR, has the wrong sign in its axial entry: the printed amplitudes imply $F_{A}^{D F} = - 22 m_{P} F_{A}^{GR}$ , not $+ 22 m_{P} F_{A}^{GR}$ . With the corrected dictionary, the GR10 amplitude agrees with the $O (p^{4})$ chiral prediction in the axial sector but carries the opposite sign to the chiral anomaly in the vector sector; the relative sign fixed in the Decker-Finkemeier addendum is confirmed in both sectors. The identification in footnote 6 of AHLRR of their value with the pre-addendum result rests on the erroneous dictionary and does not hold. The numerical impact is small: $δ r_{S D}$ shifts from $+ 0.150%$ to $+ 0.146%$ in the pion channel and from $+ 0.18%$ to about $+ 0.16%$ in the kaon channel.
hep-ph0 citations
36
Probing Neutrinophilic Long-Range Forces at DUNE
Sudip Jana🇮🇳 · Pragyanprasu Swain🇮🇳
Neutrino oscillations provide compelling evidence for physics beyond the Standard Model, while the weakly interacting nature of neutrinos makes them powerful probes of new interactions and hidden sectors. In this work, we investigate a \textit{dark neutrino portal} scenario in which neutrino mass generation is linked to a light dark sector charged under a new $U (1)_{D}$ gauge symmetry. While Standard Model fields remain neutral under $U (1)_{D}$ , the dark neutrino sector is charged and communicates with the Standard Model exclusively through active--dark neutrino mixing. The associated neutrinophilic mediator induces ultra-long-range interactions, whereby electrons and neutrons in the Earth, Moon, Sun, Milky Way, and the cosmological matter distribution generate sizable matter potentials that modify neutrino oscillations. We explore the sensitivity of the upcoming Deep Underground Neutrino Experiment (DUNE), whose long baseline and pronounced matter effects make it uniquely suited to probe such interactions. We show that DUNE can access previously unexplored regions of parameter space and demonstrate that the same underlying coupling can simultaneously give rise to sizable neutrino self-interactions, including regions relevant for alleviating the Hubble tension, while remaining consistent with current neutrino oscillation constraints.
hep-phhep-ex1 citation
37
Implications of exclusive photon leptoproduction measurements for the proton charge-radius puzzle
MMGPDs Collaboration · Muhammad Goharipour · Anoushiravan Moradi · K. Azizi
In the present study, we extend our previous analysis of the proton electromagnetic form factors (FFs) extracted from exclusive photon leptoproduction (EP) measurements in kinematic regions where the Bethe-Heitler (BH) process dominates the cross section by including all currently available high-precision EP data from the CLAS and Hall~A Collaborations. Using the same phenomenological framework, we investigate the consistency among the different data sets, determine the proton electromagnetic FFs within several fitting scenarios, and extract the corresponding charge and magnetic radii. A significant tension is observed between the CLAS 2018 measurements and the remaining EP data. We show that excluding this data set, or restricting its kinematic coverage by imposing suitable low- $∣ t ∣$ cuts, leads to stable fits with good quality and consistent FFs. For all analyses, the extracted proton charge radius is smaller than the Particle Data Group average and most determinations based on elastic electron-proton scattering. However, the results are consistent, within uncertainties, with the PRad measurement and muonic hydrogen spectroscopy. In contrast, the magnetic radius is found to be compatible with the current world average. These results demonstrate that BH-dominated EP measurements provide an independent and complementary approach to determine the electromagnetic structure of the proton and offer additional support for the small-radius solution of the proton charge-radius puzzle.
hep-phhep-ex0 citations
38
Exclusive Quark and Gluon Dijet Production as Probes of GPDs at Collider Energies
Zhuoyi Pang🇨🇳 · Paweł Sznajder🇵🇱 · Lech Szymanowski🇵🇱 · Jakub Wagner🇵🇱
We study exclusive electroproduction of dijets in the collinear factorization framework as a probe of generalized parton distributions (GPDs). For quark dijet production, we extend previous analyses by including contributions from helicity GPDs and by assessing an additional leading-order electromagnetic channel governed by elastic nucleon form factors. Furthermore, we investigate exclusive gluon dijet production. We compare our prediction to HERA data and provide projections for measurements at the future Electron-Ion Collider.
hep-phhep-exhep-thnucl-th1 citation
39
Shifted Hybrid Realization of Non-Minimal Higgs Inflation in Light of ACT DR6 and Planck Data
Nadir Ijaz🇮🇹 · Pirzada🇨🇳 · Mansoor Ur Rehman🇸🇦
We investigate non-minimal Higgs inflation in a no-scale-inspired supergravity framework and confront its predictions with the latest CMB constraints from ACT DR6 and \emph{Planck}. Working within a shifted hybrid inflation scenario, we construct an effective single-field description in which the GUT Higgs direction serves as the inflaton after stabilization of the orthogonal scalar fields. We show that the inclusion of the leading nonrenormalizable operator in the superpotential induces a controlled deformation of the Starobinsky attractor, allowing the scalar spectral index to be shifted into the range favored by recent ACT and related CMB datasets while maintaining a small tensor-to-scalar ratio, $r \sim 1 0^{- 3} - 1 0^{- 2}$ . The resulting inflationary dynamics remain theoretically consistent, with controlled supergravity corrections and sub-Planckian inflaton field values. We perform a detailed numerical analysis of the model parameter space, including reheating and nonthermal leptogenesis, and identify regions that simultaneously satisfy current observational constraints and yield a viable post-inflationary cosmological history.
hep-phastro-ph.CO4 citations
40
Possibility of the antibottom-strange molecular pentaquarks near $B Σ$ and $B^{*} Σ$ thresholds
Jian-Kang Zhao🇨🇳 · Nijiati Yalikun🇨🇳
The molecular states in coupled channel system of $B_{s}^{0} N - B Λ - B^{*} Λ - B Σ - B^{*} Σ$ are investigated within one-boson-exchange model that includes $S$ - $D$ wave mixing and a tunable short-range $δ (r)$ term. Bound, resonant, and virtual states are searched by analytically continuing the $S$ matrix in the complex energy plane. In the single-channel analysis, the $B Σ$ and $B^{*} Σ$ systems with $J^{P} = 1/ 2^{-}$ and $3/ 2^{-}$ are found to be attractive and form three bound states with reasonable cutoff region, corresponding to $1/ 2^{-} (B Σ)$ , $1/ 2^{-} (B^{*} Σ)$ , and $3/ 2^{-} (B^{*} Σ)$ . When coupled-channel dynamics is included, these states evolve into near-threshold poles that produce enhancements in the $B_{s}^{0} N$ , $B Λ$ , and $B^{*} Λ$ invariant mass spectra. The pole below the $B^{*} Σ$ threshold in the $J^{P} = 1/ 2^{-}$ system depends strongly on the treatment of the short-range $δ (r)$ term and becomes a virtual state when this contribution is removed, while the other two resonant poles and their line shapes are only moderately affected. For representative parameter region, the predicted masses of these states lie in the $6.44 - 6.52$ GeV region and have widths of a few to several MeV. The pole coupling and partial-width analyses indicate that the poles are generated mainly by the $B Σ$ and $B^{*} Σ$ channels interaction, and their observable signals are expected mainly in the lower open channels $B_{s}^{0} N$ , $B Λ$ , and $B^{*} Λ$ . These results support the existence of near-threshold molecular pentaquark $P_{b ˉ s}$ and provide useful guidance in future experimental searches.
hep-phhep-th0 citations
41
Pion Distribution Amplitudes from Functional QCD
Lei Chang🇨🇳 · Wei-jie Fu🇨🇳 · Chuang Huang🇩🇪 · Jan M. Pawlowski🇩🇪 · Yang-yang Tan🇯🇵
We present the first functional QCD calculation of the pion distribution amplitude (DA) using the large-momentum effective theory within the functional renormalisation group (fRG) approach. With only the strong coupling and current quark masses as inputs, we compute the quasi-DA from first-principles QCD correlation functions. By pushing the pion momentum up to $P_{z} = 4.5 GeV$ , the quasi-DA becomes fully saturated, rendering the extrapolation errors to the light-cone limit negligible. The resulting second-order moment $⟨ ξ^{2} ⟩_{π} = 0.267$ is significantly smaller than existing lattice-LaMET determinations and lies in a range consistent with other nonperturbative approaches.
hep-ph0 citations
42
Beyond Half-Life Limits: Robust Operator-Level Interpretation of Multi-Isotope Neutrinoless Double-Beta Decay
K. Ishidoshiro🇯🇵
Current and future neutrinoless double-beta decay ( $0 ν β β$ ) searches are usually characterized by half-life limits or projected sensitivities. For operator-level interpretation, however, the relevant question is not only the strength of the limit, but also the stability of the inferred constraints on low-energy lepton-number-violating (LNV) coefficients under changes of isotope and nuclear matrix-element (NME) method. Using $ν$ DoBe, we convert half-life limits or projected sensitivities into limits on low-energy LNV coefficients for several choices of isotope, operator class, and NME method. We then compare the resulting limits across isotopes and NME methods. We quantify the stability by the spread of coefficient limits in non-observation scenarios and, for single-operator post-discovery benchmarks, by the spread of isotope-to-isotope half-life ratios. For the operator examples considered in this paper, the light-Majorana exchange mechanism gives the most stable interpretation. The selected dimension-six operators remain reasonably robust, while the short-range dimension-nine examples show a stronger dependence on isotope and NME-method choices. The same hierarchy appears in post-discovery benchmarks based on isotope-to-isotope half-life ratios: the reliability of such tests depends on whether the predicted half-life pattern remains stable across NME methods. A multi-isotope $0 ν β β$ program therefore provides information beyond half-life reach by testing the stability of the operator interpretation. This spread-based analysis provides a practical way to identify which low-energy operator scenarios are suitable for isotope-ratio tests after a possible discovery, and which require more care before being connected to ultraviolet models of lepton-number violation.
hep-phPRD(2026)·0 citations
43
Flavor decomposition of the gravitational form factors and mechanical structure of the proton
Hyun-Chul Kim🇰🇷 · June-Young Kim🇰🇷 · Ho-Yeon Won🇫🇷
We review in the present talk a series of recent works on the flavor decomposition of the gravitational form factors of the proton and its mechanical properties within the framework of the chiral quark-soliton model. Starting from the energy-momentum tensor operator derived from the QCD instanton vacuum, we carry out the twist projection of the energy-momentum tensor operator into its twist-2 and twist-4 components, which enables us to isolate the $c$ form factor originating from the twist-4 operator. We present the flavor-decomposed mass, spin, pressure, and shear-force distributions of the proton, together with the corresponding form factors. While the up quark dominates both the mass and the spin of the proton, the strange quark is found to contribute sizably to the $D$ -term form factor. We also discuss the mechanical stability of the proton governed by the pressure and shear-force distributions.
hep-ph0 citations
44
Insight on confinement from the QCD effective charge
A. Deur🇺🇸
Like the Gell-Mann--Low coupling $α$ of QED, the effective charge $α_{g_{1}}$ is a physical, observable-defined running coupling that can serve as the QCD coupling $α_{s}$ . It can be represented by an analytic form consistent with renormalization-group evolution, light-front holographic QCD, and the world data on $α_{s}$ . As an observable, $α_{g_{1}}$ has a physically relevant analytic structure that reflects the underlying partonic dynamics. It displays, in the long-distance regime, two imaginary conjugate singularities at $Q^{2} = \pm i Λ_{s}^{2}$ , with $Λ_{s}$ the QCD scale. To connect this structure to confinement, we use known relations between $α_{s}$ and the parton dressed propagators and vertices. Since, unlike vertices, propagators characterize a field variation between separate locations, the two singularities are assigned to the propagators. This results in the parton propagators displaying a long-distance behavior $e^{- Λ_{s} ∣ x ∣/ 2} ∣ x ∣^{- 5/2 + d_{a}}$ where propagation is suppressed beyond distances of order $1/ Λ_{s}$ , as expected from confinement. This offers an intuitive interpretation of confinement as the suppression of QCD Green's functions at long distance.
hep-ph0 citations
45
Pathways and impediments towards a detection of the relic neutrino wind
Andrew J. Long🇺🇸 · Michiru Uwabo-Niibo🇰🇷 · Masahide Yamaguchi🇰🇷
A direct detection of the cosmic neutrino background (CNB) in laboratories on Earth has been called the ``holy grail'' of experimental neutrino physics, but a still more glorious prize awaits. Beyond simply detecting the presence of relic neutrinos and measuring their flux, one may aspire to measure their energy distribution, polarization, anisotropies, temporal variation, and other properties. In this work we focus on the CNB wind, which is the approximately dipolar anisotropy in the CNB flux resulting from the relative velocity of the CNB rest frame and the lab frame. We consider a CNB detection strategy based on measuring the angular distribution of recoiling electrons at the tritium $β$ -decay endpoint. In order to quantify the difficulty of detecting the CNB wind, we calculate the required exposure (detector mass times observation duration) for a $3 σ$ discovery. We find that detecting the CNB wind would require an exposure that is at least $1 0^{5}$ times larger than what's required for detecting the CNB flux alone. Additionally if the experimental energy resolution were to exceed the neutrino mass scale, then an exceptionally good control of systematic uncertainties would also be required. For nonrelativistic neutrinos, the Majorana wind signal is suppressed relative to the Dirac case by the cancellation of the leading helicity-odd angular-correlation term, leading parametrically to an exposure penalty of order $(m_{ν} / T_{ν})^{2}$ .
hep-phastro-ph.CO0 citations
46
The variable flavor number scheme to three-loop order
J. Ablinger🇦🇹 · A. Behring🇩🇪 · J. Blümlein🇩🇪 · A. De Freitas🇦🇹 · A. von Manteuffel🇩🇪 · C. Schneider🇦🇹 · K. Schönwald🇨🇭
We describe the variable flavor number scheme to three-loop order, which modifies the massless parton densities by single- and two-mass effects and introduces heavy-quark parton distribution functions for charm and bottom. A renormalization group analysis shows the validity of this picture at large scales $Q^{2}$ , where it resembles the non-power-suppressed heavy-flavor corrections completely. We also provide numerical implementations of a series of charged and neutral current Wilson coefficients.
hep-phhep-exhep-thPoS(2026)·0 citations
47
Spin Polarization of Proca Stars Formed by Gravitational Bose--Einstein Condensation
Jiajun Chen🇨🇳
We study the internal spin polarization of Proca stars formed by gravitational Bose--Einstein condensation of a three-component nonrelativistic vector field. In idealized periodic-box simulations, we decompose the aperture-averaged spin into a coherent net fraction, a local polarization fraction, and their ratio, thereby distinguishing genuine coherent core polarization from local spin density whose direction cancels inside the aperture. For independent vector components, condensation produces Proca stars that are sizably but not maximally polarized. Across an independent-component simulation ensemble, the coherent core-spin fraction has mean $⟨ χ_{net} ⟩ ≃ 0.62$ , with substantial realization-to-realization scatter. We interpret this scatter as the outcome of random elliptical polarization of the dominant component-space mode, rather than as evidence for a universal Proca-star spin fraction. This interpretation is supported by the core polarization matrix: its leading eigenvector provides an estimate of the ideal single-mode spin fraction, while the difference between this estimate and the directly integrated coherent spin tracks the departure of the core from a rank-one component-space state. The measured leading-eigenvector spin fractions are broadly compatible with an isotropic random-complex-vector model and less compatible with an equal-amplitude random-phase model. Correlated and circular initial data drive the dominant component-space mode toward the circular-polarization bound, giving the ordering independent $\to$ correlated $\to$ circular. These results show that internal polarization is a genuine vector degree of freedom of gravitationally condensed nonrelativistic Proca stars, and that the resulting core spin is controlled by the polarization of the dominant condensed mode rather than by a fixed universal value.
hep-ph0 citations
48
Parametric Resonance of Higgsed Vector Dark Matter: Inflationary Initial Conditions and Sourced Displacements
Imtiaz Khan🇨🇳 · Salvatore Capozziello🇮🇹 · G. Mustafa🇨🇳 · Niamat Ullah🇵🇰 · Farruh Atamurotov🇺🇿
Parametric resonance in a Higgsed Abelian sector provides an efficient mechanism for producing vector dark matter, but its viability depends crucially on the origin of the initial dark-Higgs displacement that seeds the resonance. In this work, we investigate this initial-condition problem in a weakly coupled Abelian-Higgs theory with potential $V = λ_{4} (ϕ^{2} - v^{2})^{2} /4$ , using the calibrated nonlinear broad-resonance relic map together with a stochastic inflationary analysis of the dark-Higgs condensate. We show that a minimal light-spectator realization fails under standard inflationary duration: while broad resonance and isocurvature constraints require $ \phi_0/H_I \gtrsim 3.3\times10^4, $ the stochastic equilibrium and finite-duration random walk produce only $ \phi/H_I=\mathcal O(1). $ This large displacement mismatch is robust against order-of-magnitude variations in the resonance efficiency and broadness threshold, establishing a model-independent obstruction to the stochastic branch. We then identify a distinct classically sourced branch, generated by a negative Hubble-induced mass, in which the condensate tracks a time-dependent minimum, $ \phi_0=\kappa H_*/\sqrt{\lambda_4}, $ and the radial fluctuation remains heavy during inflation. In this case, the fixed- $e / λ_{D}$ relic scaling shifts from $ m_X\propto \lambda_4^{5/8}H_I^{-3/2} $ to $ m_X\propto \kappa^{-3/2}\lambda_4 H_*^{-3/2}. $ We derive the simultaneous consistency conditions for this sourced branch, including broad resonance, adiabatic tracking, perturbativity, sub-Planckian displacement, thermal non-erasure, spectator backreaction, and control of inflationary vector fluctuations. Our results establish that Higgsed-vector resonance is not merely a dark-matter production mechanism, but a sensitive probe of the inflationary and reheating dynamics that determine its initial conditions.
hep-ph4 citations
49
Galactic Center Neutrinos from Cosmic Ray-Dark Matter Interactions
Jorge Terol Calvo🇮🇹 · Pedro de la Torre Luque🇪🇸 · Mainak Mukhopadhyay🇺🇸 · Chris Cappiello🇺🇸 · Gonzalo Herrera🇺🇸
The IceCube and ANTARES collaborations have recently reported evidence for high-energy neutrinos associated with the Galactic plane and the Galactic Ridge, offering a new pathway to search for dark matter (DM). Deep inelastic scattering of cosmic rays with sub-GeV DM in the Galactic halo produces a distinctive neutrino signature from meson decays. Using detailed Galactic cosmic-ray maps and ANTARES observations, we derive 99% C.L. upper limits on the DM-nucleon cross section that extend down to keV-scale masses. These results establish Galactic neutrino telescopes as a powerful, complementary probe of light DM, with substantial improvements expected from upcoming IceCube-Gen2 and KM3NeT observations.
hep-phastro-ph.HE0 citations
50
A Shock-based Interpretation of Radio and X-ray Emission in Active Galactic Nuclei
Fan Wu · Benzhong Dai🇨🇳
We propose a shock-based framework to interpret the radio and X-ray emission in active galactic nuclei (AGNs), whose origin remains an open problem. In this framework, the radio emission is produced by synchrotron radiation in the accretion flow or a jet/weak outflow, while the dominant X-ray component depends on the accretion state, the location of the non-thermal emission region, and the available seed photon field. The model provides a self-consistent interpretation of radio and X-ray emission in typical non-jetted AGNs, including low-luminosity AGNs, Seyfert galaxies, and radio-quiet quasars. In jetted AGNs, our results disfavor scenarios in which the non-thermal electrons responsible for X-ray emission are accelerated in the disk or the corona. We use two widely discussed empirical diagnostics, radio loudness and the fundamental plane (FP) of black hole (BH) activity, to assess the applicability and limitations of the model. It can naturally explain the observed trends that the radio loudness increases with BH mass and decreases with the Eddington ratio. The observed slope of the FP depends on how the key physical quantities scale with the accretion rate. As the accretion rate increases, the advection-dominated accretion flow region contracts while the thin disk region expands, reflecting a transition toward a more radiatively efficient accretion structure. The Eddington ratio therefore influences the accretion structure, and may in turn shape the observed AGN classes.
↳ astro-ph.HEhep-phApJ(2026)·0 citations
51
First Search for Kaluza-Klein Gravitons and Radion Using Planck Data
Alexander P. Cassem🇺🇸 · Soubhik Kumar🇺🇸
Heavy moduli and Kaluza-Klein (KK) gravitons from extra dimensions may evade terrestrial probes but can be produced during inflation, generating primordial non-Gaussianity (NG) through unavoidable couplings to density perturbations. In a warped five-dimensional (5D) model, we compute the full radion- and KK-graviton-mediated bispectra and perform the first search for these signals using Planck 2018 temperature and polarization data. We find no significant evidence for NG, with the maximum significance being $1.8 σ$ for $m_{KK} \approx 1.6 H$ . We also identify a 5D setup which naturally generates NG with $f_{NL} \sim 1 - 50$ , within the reach of future surveys.
↳ astro-ph.COhep-phhep-th4 citations
52
Limits on global cosmic birefringence using radio sources
Richard A. Battye🇬🇧 · Neal Jackson · Ian Browne
We have made measurements of the difference between the position angle (PA) on the sky and the polarization position angle (PPA) of radio sources using data from a combination of the Radio Fundamental Catalogue (RFC) across a range of frequencies between 2.7 and 15~GHz and Cosmic Lens All Sky Survey (CLASS) which observes polarization at 8.4~GHz (X-band). For the 2111 sources with jet PAs measured in the X-band and a known redshift, the distribution is peaked at $\approx 0^{\circ}$ as expected for no birefringence and it can be modelled by two populations: one which is a Gaussian with mean $μ_{β} = (0.2 \pm 1.0)^{\circ}$ and standard deviation $σ_{β} = (14.7 \pm 1.1)^{\circ}$ and the other a uniform distribution of sources which are a fraction $f_{β} = 0.72 \pm 0.02$ of the total. Uncertainties in $μ_{β}$ can be reduced to $\approx 0. 6^{\circ}$ by stacking measurements of the PA from other wavebands. We find that limits of $\approx 0. 1^{\circ}$ might be possible with a sample of $\sim 1 0^{5}$ similarly selected sources and that this could provide a confirmation of recent claims of global birefringence made using the Cosmic Microwave Background observations from the {\it Planck} satellite.
↳ astro-ph.COhep-phPRL(2026)·0 citations
53
Digital Quantum Simulation of Nonequilibrium Dynamics in the Schwinger Model under a Strong External Electric Field
Haobin Chen🇨🇳 · Lin Cheng🇨🇳 · Xingyu Guo🇨🇳
We use the (1+1)-dimensional Schwinger model to investigate the nonequilibrium dynamics of a finite lattice system under a constant external electric field. The lattice Hamiltonian is constructed under open boundary conditions. The vacuum state is prepared using the variational quantum eigensolver (VQE). Scans over the external field strength show the flip of the vacuum state at several field strengths. The critical field strengths agree with theoretical predictions. We further investigate the real-time evolution of the zero-field vacuum under an external electric field using a second-order Trotter-Suzuki decomposition. By comparison with exact diagonalization (ED), we verify that the quantum-simulation protocol reproduces the main features of field-induced boundary charge separation, decay of the vacuum-state fidelity, and quasiperiodic energy redistribution between the electric-field energy term and the fermionic sector. Our results indicate that combining VQE-based state preparation with digital real-time evolution provides a useful approach for studying nonequilibrium dynamics in strong-field lattice gauge theories.
↳ hep-lathep-phquant-ph0 citations
54
Decoherence Effects on Primordial Black Holes and Scalar-Induced Gravitational Waves
Waqas Ahmed🇨🇳
Primordial black holes (PBHs) form when large primordial curvature perturbations re-enter the Hubble radius and exceed the classical collapse threshold. These perturbations originate as quantum fluctuations of the inflationary vacuum, motivating a quantum-information description of the PBH-producing scalar sector. We develop a conservative extension of the standard PBH and scalar-induced gravitational-wave (SIGW) framework in which Gaussian quantum discord is used as a diagnostic of residual quantum correlations, not as a new PBH-formation criterion. We describe each $(\bm k,-\bm k)$ pair as a two-mode Gaussian state and show that, in the pure squeezed limit, discord grows rapidly with the squeezing parameter, so low discord thresholds are automatically satisfied for strongly squeezed modes. The nontrivial regime is the mixed state produced by decoherence. Using a Lindblad open-system description, we motivate a Gaussian loss channel for the scalar covariance matrix and distinguish the discord from a covariance-survival factor $Q_{\rm dec}(k)$. If the decoherence channel suppresses the scalar two-point covariance, PBH abundance can be affected through the classical collapse variance, while the SIGW spectrum is modified more directly by the factors $Q_{\rm dec}(ku)Q_{\rm dec}(kv)$ inside the radiation-era convolution. For a narrow scalar peak and slowly varying $Q_{\rm dec}$, this gives the benchmark scaling $\Omega_{\rm GW}^{\rm eff}\simeq Q_{\rm dec}^2\Omega_{\rm GW}^{\rm class}$. Thus quantum discord and decoherence provide a controlled way to characterize the quantum-to-classical transition of PBH-producing perturbations, with the clearest imprint appearing in scalar-induced gravitational waves.
↳ gr-qchep-phhep-thquant-ph0 citations
55
Evading the CMB $μ$ -distortion bound on Supermassive Primordial Black Hole seeds with Non-Gaussian tails
Sanket Dave🇨🇳 · Sheng-Feng Yan🇨🇳 · Amara Ilyas🇨🇳 · Yi-Fu Cai🇨🇳
Supermassive black holes (SMBHs) powering quasars at $z ≳ 6$ are difficult to grow from stellar mass remnants, motivating seeds from primordial black holes (PBHs) with masses $1 0^{5} - 1 0^{7} M_{⊙}$ . This range is constrained by the COBE/FIRAS bound on the CMB $μ$ -distortion, which limits the small-scale curvature variance to $σ_{ζ}^{2} ≲ 1 0^{- 4}$ . For Gaussian perturbations, the variance fixes the far tail of the one-point probability distribution function (PDF), making the PBH abundance negligible. We call this the Gaussian barrier. The barrier can be evaded only if the variance probed by the distortion is decoupled from the tail probability controlling collapse. We implement this idea in the non-perturbative $δ N$ formalism and relate asymptotic PDF tails to the global shape of the $δ N$ map. Four Gaussian-cored families are analyzed: generalized-normal, stretched-exponential, power-law, and log-normal tails. After standardizing each family to unit variance, we impose the FIRAS cap and compute the distortion-limited PBH abundance in the tail-shape parameter space. The ordinary exponential tail produced by standard single-field non-attractor dynamics is still too light to reopen the seed window. Algebraic tails from fractional-potential dynamics, and sufficiently heavy log-normal tails treated as a phenomenological proxy for multiplicative dynamics, can supply seed-relevant abundances while respecting the distortion bound.
↳ astro-ph.COgr-qchep-phhep-th1 citation
56
Neutrino mass constraints in the Schwarzschild-de Sitter black-hole dark energy model with ACT DR6 and DESI DR2 data
Sheng-Han Zhou🇨🇳 · Tian-Nuo Li🇨🇳 · Guo-Hong Du🇨🇳 · Yi-Min Zhang🇨🇳 · Zhao-Yu Li🇨🇳 · Jing-Fei Zhang🇨🇳 · Xin Zhang🇨🇳
Recent DESI observations have posed new challenges to $Λ$ CDM, showing a preference for dynamical dark energy and yielding neutrino mass constraints within $Λ$ CDM that approach the lower bound allowed by neutrino oscillation experiments. In this work, we investigate cosmological constraints on the key neutrino parameters, $\sum m_{ν}$ and $N_{eff}$ , within the Schwarzschild-de Sitter black-hole dark energy (SdSDE) framework. We use cosmic microwave background (CMB) data from Planck and ACT DR6, baryon acoustic oscillation data from DESI DR2, and type Ia supernova data from DES-Dovekie and PantheonPlus. We find that SdSDE scenarios prefer a positive neutrino mass whenever $\sum m_{ν}$ is allowed to vary. Using CMB+DESI+DES-Dovekie data, we obtain $\sum m_{ν} = 0.20 7_{- 0.052}^{+ 0.047} eV$ for SdSDE+ $\sum m_{ν}$ , reduced to $\sum m_{ν} = 0.16 2_{- 0.056}^{+ 0.055} eV$ when $N_{eff}$ is also varied. This arises from the positive correlation between $N_{eff}$ and $\sum m_{ν}$ , together with the systematic preference of SdSDE for values of $N_{eff}$ below the standard value. Furthermore, the best-fit $χ^{2}$ comparison shows that $Λ$ CDM with extended neutrino parameters is strongly preferred over the corresponding SdSDE extension. Overall, the positive neutrino mass preference induced by SdSDE may reflect parameter compensation rather than an improved global fit, a possibility that should be further tested with future high-precision observational data.
↳ astro-ph.COastro-ph.GAgr-qchep-ph1 citation
57
Running of the Electroweak Gauge Couplings from First Principles
Alessandro Conigli🇩🇪 · Dalibor Djukanovic🇩🇪 · Georg von Hippel🇩🇪 · Simon Kuberski🇨🇭 · Harvey B. Meyer🇩🇪 · Kohtaroh Miura🇯🇵 · Konstantin Ottnad🇩🇪 · Andreas Risch🇩🇪 · Hartmut Wittig🇩🇪
We present a high-precision calculation of the hadronic running of electroweak gauge couplings from first principles. Employing lattice QCD in the low-energy regime, we achieve permille precision for virtualities $Q^{2} ≲ 12 GeV^{2}$ . At $Q^{2} ≃ 1 GeV^{2}$ , our determination deviates by up to $7 σ$ from estimates based on $e^{+} e^{-}$ measurements. Combining lattice QCD with perturbative QCD via the Euclidean split technique, we obtain for the electromagnetic coupling $Δ α_{had}^{(5)} (M_{Z}^{2}) = 0.027821 (34)_{lat} (35)_{pQCD}$ , which is more than twice as precise as recent phenomenological determinations. We assess improvement scenarios by which the precision target for next-generation electroweak measurements could be reached.
↳ hep-lathep-phPRL(2026)·2 citations
58
Pulsar Timing Sensitivity to Dark Matter Substructure in the Presence of a Stochastic Gravitational-Wave Background
Abhiram Cherukupalli🇺🇸 · Vincent S. H. Lee🇺🇸 · Kim Berghaus🇺🇸 · Kathryn M. Zurek🇺🇸
Pulsar timing arrays (PTAs) can detect dark matter (DM) substructure through the small shifts a transiting DM subhalo imprints on pulse arrival times. Recently found evidence for a stochastic gravitational-wave background (GWB) acts as red noise and competes with the substructure signal. Here we provide an analytic understanding of how this background degrades PTA sensitivity to DM substructure. We derive the full gauge-invariant proper-time observable induced by a transiting DM subhalo and develop a framework for the expected signal-to-noise ratio in the presence of red noise, accounting for the degeneracy with the pulsar timing model. From this we obtain simple scaling relations for the reach across the static, dynamic, and stochastic regimes, and numerically compute the reach for a Square Kilometre Array benchmark at three representative points of the NANOGrav 15-year posterior. The GWB background suppresses the sensitivity to DM substructure by one to three orders of magnitude compared to forecasts in the presence of only white noise, and the suppression depends on the amplitude and spectral index of the background within a factor of three. The dynamic Shapiro signal suffers the smallest suppression and gives the best sensitivity to DM substructure near $1 0^{- 2} M_{⊙}$ . Probing the regime where subhalos make up all or part of the DM remains a challenge even for surveys with more pulsars and longer observing time. Despite this, PTA measurements remain a competitive probe of DM substructure, and future surveys will increase in sensitivity by up to two orders of magnitude from existing NANOGrav limits.
↳ astro-ph.COhep-ph1 citation
59
Black Hole Memory Burden and its Signatures in Gravitational Waves from Mergers
Gia Dvali🇩🇪 · Michael Zantedeschi🇮🇹 · Sebastian Zell🇩🇪
Swift memory burden (MB) implies that the information stored in a black hole (BH) can modify its classical dynamics when the BH is perturbed. This influences the gravitational waves (GWs) emitted during BH mergers. In this paper, we investigate how the BH memory load is determined by the features of the collapsing source. We show that the memory load can vastly exceed the information content of its progenitor. An extreme example is a BH formed in a two-particle collision, which exhibits maximal MB. We then derive bounds for BHs formed through stellar collapse and examine the impact of swift MB on BH quasinormal modes, quantifying the MB-induced frequency shift of GWs. These findings imply that GW observations probe the fundamental mechanisms of BH information storage as well as their formation history.
↳ gr-qcastro-ph.COhep-phhep-th2 citations
60
Relativistic Vorticity in the Quark-Gluon Plasma: Generation Symmetries, Explosive Dilution, and Azimuthal Spin Alignment
Malak Ait Tamlihat🇲🇦 · Ghizlane Ez-Zobayr🇲🇦 · Laurent Schoeffel🇫🇷 · Yahya Tayalati🇲🇦
This article provides a self-contained bridge between classical vortex dynamics and the relativistic, subatomic domain of the Quark-Gluon Plasma (QGP) produced in ultra-relativistic heavy-ion collisions. While the QGP is widely studied for its near-perfect fluidity, we focus on its role as the most vortical medium in the Universe ( $ω \sim 1 0^{22} s^{- 1}$ ). The originality of our approach lies in isolating the explicit physical competition between non-linear vortex stretching and violent relativistic volumetric dilatation. By solving the covariant transport equations and tracking the comoving enstrophy density, we demonstrate that the explosive kinematics of the QGP provide an innate geometric shield that naturally regularizes the continuous flow, suppressing the self-amplification of vortex tubes before any microscopic viscosity is required. Furthermore, we connect this expansion phase back to the highly non-equilibrium initial state. We quantitatively predict that under a peripheral dipole initial topology, the global mid-rapidity hyperon polarization vanishes ( $P_{Λ} ≲ 1 0^{- 4}$ ), establishing that the definitive signature of the QGP's rotation must be sought in azimuthal differential measurements within the LHC and RHIC experimental programs.
↳ nucl-thhep-ph0 citations
61
Neutron stars with an agnostic Dark sector: Core and Halo configurations from a two-fluid approach
Asit karan🇮🇳 · Asim Kumar Saha🇮🇳 · Tuhin Malik🇵🇹 · Constança Providência🇵🇹 · Ritam Mallick🇮🇳
The study of dark matter admixed neutron stars has the potential to advance our understanding of dark matter particle candidates. However, the large parameter space of dark matter particle masses restricts a systematic, model-independent study. In this analysis, we employ agnostic hadronic and dark matter equations of state to construct dark-matter-admixed neutron stars within a two-fluid formalism. Dark matter is characterised solely by its low-density equation of state and mass, and is modelled as a Fermi gas, while hadronic matter is anchored at low and high densities by chiral effective field theory and perturbative quantum chromodynamics calculations. A speed-of-sound parametrisation covers the intermediate density region for hadronic matter and the high-density region for dark matter, so the dark matter equation of state is constrained only by thermodynamic consistency, free from bias toward a softer or stiffer equation of state. Within this agnostic framework, we find that dark matter does not generically compactify the star: light dark matter forms extended halos that raise the tidal deformability, while heavy dark matter forms compact cores that lower it. Consequently, the dominant observational constraint shifts from gravitational-wave tidal deformability for light, halo-dominated models to NICER mass--radius data for heavy, core-dominated models. Using current data at $1 σ$ , we constrain the dark matter fraction to $f_{DM} ≲ 0.11$ for light dark matter. Being almost independent of any assumed dark-sector microphysics, our framework yields conservative, broadly applicable bounds on the dark-matter content of neutron stars. Neutron stars with similar masses but very different tidal deformabilities could be a smoking-gun signature of dark matter in Neutron stars.
↳ astro-ph.HEhep-ph0 citations
62
Identifying lensed gravitational waves with physics-informed posterior learning
Tian-Yang Sun🇨🇳 · Xiao Guo🇨🇳 · Jing-Fei Zhang🇨🇳 · Xin Zhang🇨🇳
Gravitational lensing of gravitational waves can probe compact lenses, dark matter substructure, and cosmological distances, but identifying lensed events is difficult when unrelated binary mergers overlap in the same analysis window. We develop physics-informed posterior learning for ranking lensed multi-image signals against unrelated multiple-merger events. The method exploits the geometric-optics consistency that lensing can change amplitudes, arrival times, and Morse phase offsets while preserving the intrinsic phase evolution of the source. We infer a simulation-trained approximate posterior for the common detector-frame chirp mass and symmetric mass ratio, and fuse posterior samples with direct waveform features. Training uses generic multi-image simulations, while point-mass, singular-isothermal-sphere, singular-isothermal-ellipsoid, and shear-perturbed lenses are reserved for held-out lens-family evaluation. For the observationally motivated binary-black-hole population, the fusion ranking raises the detection efficiency from $20.8%$ to $35.2%$ at a $1%$ reference false-positive-rate threshold calibrated on the corresponding unrelated multiple-merger sample. It lowers the network signal-to-noise ratio needed for $50%$ detection efficiency from 45.3 to 33.5, which corresponds to a 1.35 times larger signal-to-noise-ratio-equivalent distance scale. The gain is limited by loud unrelated multiple-merger events that are partly source consistent, and by the need to calibrate the unrelated multiple-merger population. These results suggest that physical consistency can become a guiding principle for machine learning searches in dense gravitational-wave catalogs.
↳ gr-qcastro-ph.COastro-ph.IMhep-ph1 citation
63
Relativistic Hydrodynamics and Vorticity Dynamics in High-Energy Heavy-Ion Collisions: A Collective Flow Perspective
Malak Ait Tamlihat🇲🇦 · Ghizlane Ez-Zobayr🇲🇦 · Laurent Schoeffel🇫🇷 · Yahya Tayalati🇲🇦
This article provides a comprehensive overview of the application of relativistic fluid mechanics to describe the collective evolution of the Quark-Gluon Plasma (QGP) formed in ultra-relativistic heavy-ion collisions. We map out the chronological transformation of spatial eccentricities in the initial interaction volume into measurable anisotropic azimuthal momentum distributions, parameterized by the harmonic flow coefficients $v_{n}$ . Utilizing multi-particle correlation techniques developed within the ATLAS experimental framework, we dissect the event-by-event fluctuations of the participant planes and evaluate non-linear hydrodynamic responses across higher harmonics. Furthermore, we embed local rotation fields into this continuous description by solving the covariant transport equations for subatomic vorticity. We demonstrate that while the Helmholtz-Kelvin theorem guarantees the topological conservation of vortex lines within the ideal medium, the collective multi-dimensional expansion forces a systematic 1/t power-law geometric dilution of the local rotational magnitude. Finally, we contrast different pre-equilibrium generation mechanisms and evaluate their final signatures on differential spin alignment observables.
↳ nucl-thhep-ph0 citations
64
First measurement of the masses of the $Υ_{1} (1 D)$ and $Υ_{3} (1 D)$ states and the energy dependence of the cross sections for $e^{+} e^{-} \to Υ_{J} (1 D) η$ and $e^{+} e^{-} \to Υ_{J} (1 D) π^{+} π^{-}$
Belle · Belle II Collaborations: M. Abumusabh · I. Adachi · K. Adamczyk · A. Aggarwal · H. Ahmed · Y. Ahn · M. Akdag · N. Akopov · S. Alghamdi · M. Alhakami · N. Althubiti and 387 other authors
We study the processes $e^{+} e^{-} \to Υ_{J} (1 D) η$ and $e^{+} e^{-} \to Υ_{J} (1 D) π^{+} π^{-}$ at center-of-mass energies $s$ =(10.73 -- 11.02) GeV using a $142.5 fb^{- 1}$ data sample, including 122~fb $^{- 1}$ near the $Υ$ (10860) peak ( $s$ = 10.866 GeV), collected with the Belle detector at the KEKB asymmetric-energy $e^{+} e^{-}$ collider. From the peak sample, the products of Born cross section times branching fraction are obtained for $σ_{Born} (e^{+} e^{-} \to Υ_{J} (1 D) η)$ or $σ_{Born} (e^{+} e^{-} \to Υ_{J} (1 D) π^{+} π^{-})$ and $B (Υ_{J} (1 D) \to χ_{b 1} γ)$ or $B (Υ_{J} (1 D) \to χ_{b 2} γ)$ for each $Υ_{J} (1 D)$ state. The corresponding branching fractions for $Υ (10860)$ decays are also obtained. The significances of the $Υ_{1} (1 D)$ , $Υ_{2} (1 D)$ , and $Υ_{3} (1 D)$ signals are 4.8 $σ$ , $> 10 σ$ , and 3.0 $σ$ , respectively, including systematic uncertainties. The mass for $Υ_{2} (1 D)$ is measured to be $(10167.0 \pm 1.0 \pm 0.2)$ MeV/ $c^{2}$ , where the first and second uncertainties are statistical and systematic. The mass splittings $Δ m_{12} = m (Υ_{2} (1 D)) - m (Υ_{1} (1 D))$ and $Δ m_{23} = m (Υ_{3} (1 D)) - m (Υ_{2} (1 D))$ are $(11.8 \pm 1.5 \pm 0.4)$ MeV/ $c^{2}$ and $(7.6 \pm 2.4 \pm 0.6)$ MeV/ $c^{2}$ , respectively.~We determine the energy dependence of the cross sections for $e^{+} e^{-} \to Υ_{J} (1 D) η$ and $e^{+} e^{-} \to Υ_{J} (1 D) π^{+} π^{-}$ for the $Υ_{1} (1 D)$ , $Υ_{2} (1 D)$ , and $Υ_{3} (1 D)$ states, combined.
↳ hep-exhep-ph0 citations
65
Reflection polarization of close binaries as a probe of axion dark matter birefringence
Tomoki Matsuoka · Kimihiro Nomura🇯🇵 · Hidetoshi Omiya🇯🇵
We propose close binary polarimetry as a probe of birefringence induced by ultralight axion dark matter. In a close binary, reflection or scattering can generate a small linear polarization whose time dependence is locked to the orbital phase. This phase-locked polarization provides a template against which an oscillatory rotation of the polarization angle induced by the axion can be searched for. We show that axion birefringence appears as sidebands around the orbital harmonics. For a single bright binary, with parameters motivated by observed systems and current high-precision optical polarimetry, we estimate the sensitivity to the axion-photon coupling under white noise assumption to be the level of $1 0^{- 12}$ GeV $^{- 1}$ at an axion mass of $1 0^{- 20}$ eV. A future array of suitable binaries could further improve the sensitivity to $1 0^{- 13}$ GeV $^{- 1}$ in an optimistic scenario. This method could provide a complementary high-cadence optical probe of axion birefringence, compared to existing astrophysical searches.
↳ astro-ph.COastro-ph.SRhep-ph1 citation
66
Equation of state of QCD(-like) theory using Lattice Monte Carlo simulations
Etsuko Itou🇯🇵
The equation of state (EoS) of strongly interacting matter at low temperature and high baryon density is a central ingredient in the physics of compact stars, but it is still difficult to determine directly from first-principles QCD calculations because of the sign problem. Two-colour QCD (QC $_{2}$ D) provides a useful and controllable laboratory: for an even number of fundamental flavours the fermion determinant is real and positive, while the theory shares the nonperturbative properties with three-colour QCD at least zero chemical-potential regime. In this short review we summarize recent lattice progress on dense QC $_{2}$ D, with emphasis on the phase structure, the emergence of superfluidity, the Bose--Einstein-condensation (BEC) to Bardeen--Cooper--Schrieffer(BCS) crossover, and thermodynamic quantities. A particularly interesting outcome is that the sound velocity in the cold dense superfluid regime can exceed the conformal value $c_{s}^{2} / c^{2} = 1/3$ . This behaviour, now seen in the simulations for several QCD-like theories, gives a stiff strongly interacting matter. It is expected to offer insight into at least some aspects of the physics realized inside neutron stars.
↳ nucl-thhep-lathep-ph0 citations
67
Revisiting the Wess-Zumino-Witten Term in Nuclear and Quark Matter under Magnetic Fields and Rotation
Markus A. G. Amano🇯🇵 · Minoru Eto🇯🇵 · Muneto Nitta🇯🇵 · Shin Sasaki🇯🇵
We study anomalous Wess-Zumino-Witten terms associated with the chiral anomaly in dense QCD matter under magnetic fields and rotation. By introducing electromagnetic, baryon number, and isospin background gauge fields, we write down the topological couplings of neutral mesons for the $N_{f} = 2$ and $N_{f} = 3$ cases. The resulting terms contain characteristic contributions proportional to $B \cdot \nabla ϕ$ and $Ω \cdot \nabla ϕ$ , where $ϕ$ denotes $π^{0}$ , $η$ , or $η^{'}$ . These results are relevant to chiral soliton lattices in dense rotating matter.
↳ hep-thhep-ph2 citations
68
Watts per event: evaluating Sustainability of HEP Event Generators beyond the LHC era
Szabolcs Molnár🇭🇺 · Gábor Bíró🇭🇺 · Gábor Papp🇭🇺 · Gergely Gábor Barnaföldi🇭🇺
The development, tuning and operation of Monte Carlo event generators beyond the LHC era require vast amount of resources. In this study we investigate the sustainability of these software with a containerized set of tools (named 77rev/propripy), by benchmarking the HIJING++ heavy-ion Monte Carlo event generator. We analyze the performance of various CPU architectures and show that by choosing the level of multithreading properly, the cost of event generation can be optimized. The presented approach can reduce the energy footprint of high-energy physics event generators and therefore alleviate the ever-increasing, ubiquitous computational challenges.
↳ physics.comp-phcs.DChep-ph0 citations
69
Alleviating the Hubble Tension with Smooth Sign-Switching Dark Energy: Full CMB Constraints with DESI and PantheonPlus
Mariam Bouhmadi-López🇪🇸 · Hsu-Wen Chiang🇨🇳 · Beñat Ibarra-Uriondo🇪🇸
Sign-switching dark energy has recently been proposed as a minimal modification of the late-time expansion history aimed at alleviating tensions within the standard cosmological model. In this work, we investigate ECDM, a smooth realisation of this scenario, with the dark energy density gradually transitioning from a negative to a positive value. We develop a consistent formulation of the perturbation equations that remains well behaved even when the dark energy equation-of-state parameter diverges during the transition. We confront the model with a comprehensive set of cosmological observations, including cosmic microwave background measurements from Planck 2018, ACT DR6 and SPT-3G, baryon acoustic oscillation measurements from DESI DR2, Type Ia supernova distances from Pantheon+, and local Hubble constant measurement of SH0ES. The inclusion of perturbations allows us to assess the impact of the model on structure growth and CMB anisotropies, providing a more thorough test of sign-switching dark energy. Our results show that this class of models is fully compatible with current precision cosmological observations while alleviating the Hubble tension and providing a compelling modification of the late-time dynamics of the Universe.
↳ astro-ph.COgr-qchep-phhep-th4 citations
70
The emergence of X-ray emission lines during relativistic radio-jet formation in the changing-look active galactic nucleus 1ES 1927+654
Dev R. Sadaula · Sibasish Laha · Eileen T. Meyer · Onic I. Shuvo · Main Pal · Ritesh Ghosh · Matteo Guainazzi · Fabio Pacucci · Stefano Bianchi · Luigi Gallo · Rostom Mbarek · Amelia M. Hankla and 18 other authors
We present results from a comprehensive multi-wavelength monitoring campaign of the changing-look active galactic nucleus 1ES 1927+654 during the onset and evolution of a relativistic radio jet $\sim$ (May 2022 - August 2025), using observations from XMM-Newton, Swift, TNG, ZTF, VLA, and VLBA. The soft X-ray emission lines at $\sim 0.56$ keV and $\sim 1$ keV have appeared with variable strength and width during the formation of the nascent jet. We note that the $\sim 1$ keV feature has been persisting since the post-2017 flare phase. We also report the detection of a broad ( $\sim 800$ eV) FeK emission feature at $(6 - 7)$ keV in the $\sim 70$ ks stacked EPIC-pn spectra, marking the first such detection, which historically was lacking in this source. The joint spectral fitting of XMM-Newton EPIC-pn and RGS data reveals the presence of ionized absorbers in 2022 ( $lo g ξ /erg cm s^{- 1} \sim 1.5 \pm 0.3$ , $N_{H} \sim 2.5 \pm 0.9 \times 1 0^{20} c m^{- 2}$ ), but weaker than that detected during the high accretion state in 2018 (Eddington ratio, $λ_{Edd} > 1$ ). The absorption features further weakened in 2023-2025 and were marginally detectable ( $N_{H} \leq 1 0^{20} c m^{- 2}$ ). The entire scenario is suggestive of a real-time transition of the accretion flow (from $λ_{Edd} > 1$ to $λ_{Edd} \sim 0.3$ ) during which the winds become weaker and the jet starts to form and evolve. Furthermore, both the soft X-ray $(0.3 - 2)$ keV and 5 GHz radio fluxes, which increased by factors of $\sim 10$ and $\sim 60$ , respectively, since 2022, have recently plateaued at elevated levels, indicating a stabilized accretion disk, corona, and jet configuration.
↳ astro-ph.HEastro-ph.GAhep-ph0 citations

Affiliations

first authorsco-authorsvia INSPIRE