HEP Phenomenology·hep-ph

Tue·Sep 15, 2026Tuesday·September 15, 2026

56 papers—42 primary·14 cross-listed

01
Flavor Flux Correlators, Forward-Backward Asymmetries, and Anomalies
Kyle Lee🇺🇸 · Ian Moult🇺🇸
Flavor plays a crucial role in the structure of the Standard Model. As such, many important collider physics measurements incorporate the flavor information of detected hadrons. Recent progress in the study of energy correlators has enabled collider physics measurements of energy flux to be reformulated as operator statements. In this Letter, we introduce flavor flux correlators, which measure the angular distribution and correlations of flavor quantum numbers. We emphasize a unique feature of heavy flavor flux correlators as compared to correlators of other charges, namely the $b$ and $c$ flavor quantum numbers are gapped at the heavy quark mass scale, making them a particularly clean perturbative observables, with $O (Λ_{QCD} / m_{Q})$ suppressed non-perturbative power corrections. As an application, we reformulate the heavy quark forward-backward asymmetry as a macroscopic consequence of a mixed electroweak anomaly of the heavy-quark flavor current. Using the relation to the anomaly, we compute the flavor flux correlator analytically at next-to-next-to-next-to-leading order and verify using parton shower simulations that non-perturbative corrections are suppressed, as expected from the gapped nature of the heavy flavor quantum numbers. Flavor flux correlators can be measured using archival electron-positron collision data, as well as at Belle II and future colliders.
hep-phhep-ex0 citations
02
Predictive Non-Minimal SU(5) GUT
Ilja Doršner🇭🇷 · Mijo Matković🇭🇷 · Shaikh Saad🇸🇮
Breaking of $S U (5)$ down to the Standard Model gauge group can be implemented by any non-trivial self-conjugate scalar representation with a suitable vacuum expectation value. The Georgi-Glashow model accomplishes this breaking with a 24-dimensional representation. That choice, although the most economical one, fails to unify the gauge coupling constants. Moreover, subsequent breaking of the Standard Model down to $S U (3) \times U (1)_{em}$ with a $5$ -dimensional representation fails to simultaneously provide viable masses for the down-type quarks and the charged leptons. We show that the substitution of the $24$ -dimensional representation with a $75$ -dimensional representation fixes the gauge coupling unification issue outrightly. We furthermore pin down, by computing the full mass spectrum of the multiplets in $75$ -dimensional representation, the range of the unification scale $m_{GUT}$ to be $1 0^{15} GeV ≲ m_{GUT} ≲ 1 0^{16} GeV$ . This unification window is partially excluded by Super-Kamiokande data and will be experimentally accessible at Hyper-Kamiokande. The second issue with the Georgi-Glashow model can be addressed, for example, with vectorlike fermions. The $24$ -dimensional scenario admits three different types of vectorlike fermions that can properly account for the mismatch between the down-type quark and the charged lepton masses. The $75$ -dimensional scenario, on the other hand, offers enhanced predictivity by allowing only a unique vectorlike addition of $1 0_{F} + 10_{F}$ that restores realistic charged fermion masses and modestly pushes the upper limit on the unification scale to $m_{GUT} ≲ 3 \times 1 0^{16} GeV$ . The proposed framework with $75$ -dimensional scalar representation can thus serve as a phenomenologically viable alternative to the standard Georgi-Glashow symmetry breaking paradigm.
hep-ph0 citations
03
Semi-visible Jets from Sneaky Dark Matter
Deepak Kar🇿🇦 · Christiane Scherb🇺🇸 · Pedro Schwaller🇩🇪 · Sukanya Sinha🇬🇧
In this paper, we compare two different ways of generating semi-visible jet signature in non-resonant production mode, and flag the potential advantages of the new generation approach we propose. In addition, we suggest a more efficient matrix element to parton shower matching configuration for this hadronic final state signature. Finally, we perform a reinterpretation study of the ATLAS search for t-channel semi-visible jet production and obtain collider limits on the sneaky DM scenario.
hep-phhep-ex0 citations
04
Direct detection of right-handed fermionic dark matter: electron-recoil measurements in Xe atoms
Santiago Collazo🇦🇷 · Carlos Argüelles🇦🇷 · Soroush Shakeri🇮🇷 · Osvaldo Civitarese🇦🇷
We present theoretical estimations of the event rates for the interaction between a right-handed fermionic dark matter with an electron bound to a xenon atom. Motivated by recent astrophysical and cosmological constraints on a fermionic dark matter candidate in the sub-MeV mass range, we study such an interaction through an effective electromagnetic channel where the output consists of standard-model particles. This mechanism allows right-handed neutral dark matter fermions to couple with standard-model particles with the interchange of $W^{\pm}$ or $Z$ bosons, without the need to add extra fields. We generalize and extend previous results on this type of channels, by including for the ionization form factor arising from the interaction of the fermionic candidate with bound electrons. In addition, we compute the sensitivity curves for different direct detection experiments in such a challenging light particle mass range.
hep-phastro-ph.CO0 citations
05
A Unified Numerical Study of Axion Stars: From the Nonrelativistic Regime to General Relativity
Parisa Arabameri🇨🇱 · Paola Arias🇨🇱 · Francisco Colipí-Marchant🇨🇱 · Enrico D. Schiappacasse🇨🇱
Axion-star mass-radius relations are commonly computed using different orders of relativistic approximation, making it important to determine where these descriptions remain reliable. We perform a unified numerical comparison of axion-star ground-state configurations in the Newtonian Schrödinger-Poisson description, first- and second-order relativistic effective field theories, and the full Einstein-Klein-Gordon system for a real scalar field. Using the same attractive quartic self-interaction in all four descriptions, we scan $∣ λ ∣ = (M_{Pl} / f_{a})^{2}$ and determine the maximum masses and corresponding enclosed-mass radii. All descriptions recover the common large- $∣ λ ∣$ dilute-star scaling, while substantial differences appear at weak and moderate coupling. The relativistic EFTs interpolate systematically between the Newtonian and full-GR results. For part of the maximum-mass sequence where $max ∣ ϕ ∣/ f_{a} = O (1)$ , we test the temporal-harmonic and potential truncations explicitly in full GR. The higher-harmonic expansion shows rapid convergence, while restoring the complete single-cosine potential changes the maximum mass only at the percent level and $R_{95}$ at the several-percent level. Together with the systematic convergence of the relativistic EFT descriptions toward full GR, these results show that the large weak-coupling departure from the Schrödinger-Poisson prediction reflects the breakdown of the nonrelativistic structural description. Our results provide a systematic benchmark for determining when Newtonian, relativistically corrected, or fully general-relativistic descriptions are required for axion-star structure. The numerical implementation used in this work is available in the Axion Star Solvers repository at https://github.com/Parisa-Arabameri/AxionStar.
hep-phastro-ph.COastro-ph.GAgr-qc+10 citations
06
Lorentz Violation and Vector Meson Dominance
Brett Altschul🇺🇸
Vector meson dominance models describe the mixing of photons with vector mesons; the hadronic admixture frequently dominates the interactions of photons with nucleons. This mixing also makes it possible to test for new physics affecting the vector mesons using photon measurements. The possibilities for new physics to be contrained in this indirect fashion include potential Lorentz and CPT violations in the hadronic effective action. The characteristic scale of bounds on Lorentz violation coefficients in the $ρ^{0}$ meson sector is two orders of magnitude weaker than the corresponding photon bounds, three orders of magnitude weaker for $ϕ$ vector mesons, and four orders of magnitude weaker for $ω$ mesons.
hep-phhep-th0 citations
07
Polarized Semi-Inclusive Deep-Inelastic Scattering at $O (α_{s}^{3})$ in QCD
Liang Dong · Shen Fang🇨🇳 · Jun Gao🇨🇳 · Hai Tao Li · Ding Yu Shao🇨🇳 · Bin Zhou · Yu Jiao Zhu🇩🇪
Unraveling the partonic origin of the proton spin requires precise determinations of polarized parton distribution functions (PDFs), which depend on comparably precise theoretical predictions for polarized scattering, particularly in view of the high-precision measurements anticipated at the future Electron-Ion Collider. We present the first next-to-next-to-next-to-leading order (N $^{3}$ LO) QCD predictions for longitudinally polarized semi-inclusive deep-inelastic scattering (SIDIS) in a fully differential form, together with next-to-next-to-leading order predictions for the hadron transverse-momentum spectrum. These results are obtained by extending the two-dimensional transverse-momentum subtraction framework to the spin-dependent cross section. Together with the corresponding unpolarized calculation, these results enable consistent N $^{3}$ LO predictions for longitudinal double-spin asymmetries and provide a precision baseline for future analyses of helicity PDFs and transverse-momentum-dependent helicity distributions.
hep-phhep-ex0 citations
08
Invariant Algebras of Low-Rank Neutrino Matter Flows: Krylov-Plücker Invariants, the $3 + 1$ Toric Ring, and Controlled Deformations
Jianlong Lu🇸🇬
Matter changes the eigenvalues and mixing matrix of the neutrino propagation Hamiltonian while entering the flavor-basis Hamiltonian through a low-dimensional additive deformation. We develop a unified algebraic description of the quantities that are insensitive to this deformation. The invariant algebra is formulated as the joint kernel of commuting matter-translation derivations inside the flavor-rephasing invariant ring. For diagonal matter potentials, this gives a general decomposition into unaffected diagonal directions and an off-diagonal cycle algebra, together with an exact dimension formula for an arbitrary number of flavors and independent matter parameters. For matter spurions with common low-rank support, block-Krylov rows generate exterior-power covariants whose maximal minors are matter independent. Their mass-basis form is a Plücker expansion: rank one produces the familiar Vandermonde factorization, whereas higher rank generically produces a sum of independent Plücker terms. The standard $3 + 1$ system provides our principal nontrivial example. Its global off-diagonal algebra is the toric cycle ring of the complete four-vertex flavor graph, generated by edge moduli, triangle cycles, and quadrangle cycles; the commonly used eleven invariants constitute a generic local coordinate system rather than a global polynomial generating set. We further formulate independently varying matter compositions and off-diagonal nonstandard interactions as, respectively, commuting exact flows and controlled deformations of the invariant algebra. This framework separates the existence of exact invariants from the stronger and exceptional property of single-monomial spectral factorization.
hep-ph0 citations
09
Probing Neutrinophilic Scalars in Muon Decays
Yongchao Zhang🇨🇳 · Zhong Zhang🇨🇳
The non-standard self-interactions of neutrinos could be induced by (light) scalars that couple primarily to neutrinos. In this work, we investigate the effects of neutrinophilic scalars $ϕ$ on muon decays at the tree, 1-loop and 2-loop levels, considering both Dirac and Majorana neutrinos. The most phenomenologically interesting processes are the 1-loop corrections of $ϕ$ to the SM muon decay and the four-body muon decays $μ^{-} \to e^{-} ν_{μ} ν_{μ} ϕ, e^{-} ν ˉ_{e} ν ˉ_{e} ϕ$ , both induced by the coupling $h_{e μ}$ of $ϕ$ to Majorana neutrinos. The infrared divergences in these processes cancel with each other, yielding an infrared-safe inclusive decay width. The precise $G_{F}$ measurements constrain the coupling $∣ h_{e μ} ∣$ down to roughly $0.027$ , with the scalar mass $m_{ϕ}$ constrained up to roughly $5.9$ TeV. For $m_{ϕ} ≳ O (GeV)$ , the $G_{F}$ measurements are more stringent than other existing laboratory, astrophysical and cosmological constraints. Some other $ϕ$ -induced processes are also possible, which are, however, heavily suppressed by the small couplings, tiny neutrino masses and/or the loop factor.
hep-phhep-ex0 citations
10
From cross-section degeneracies to phase-sensitive observables in near-threshold J/psi production
Arkadiy I. Syamtomov🇺🇦
Near-threshold $J / ψ$ production is sensitive to scalar and traceless spin-two chromoelectric structure in the nucleon. We study whether present integrated and differential measurements can separate these contributions and constrain their relative phase. The GlueX integrated cross section does not determine a unique scalar contribution: production and elastic scalar terms are strongly correlated, while flatter non-forward profiles drive the fitted scalar strength to zero. In a 38-point large- $ξ$ differential analysis, the scalar term is collinear at fixed kinematics with the retained C-GFF direction, leading to nearly degenerate solutions and strong profile dependence. A common single-channel final-state factor preserves the scalar-spin-two relative phase, whereas coupled-channel rescattering can modify it. Its determination therefore requires polarization-sensitive observables together with process-specific complex helicity amplitudes.
hep-phhep-ex0 citations
11
Reliable Hybrid Neural Surrogates for Multidimensional Grids: Application to Double Parton Distributions
R. Kord Valeshabadi🇮🇷 · S. Rezaie🇮🇷
The conventional grid-based approach used for storing and evaluating ordinary parton distribution functions (PDFs), as implemented for example in LHAPDF, becomes much more demanding for double parton distributions (DPDs). While a collinear PDF depends on one longitudinal momentum fraction and one factorization scale, an unequal-scale DPD depends on two momentum fractions and two independent factorization scales for every parton-flavor combination. Direct tabulation of this four-dimensional dependence therefore requires considerably more disk space and runtime memory. In this work, we develop a hybrid neural-network method for compact storage and fast evaluation of $y$ -independent unequal-scale DPDs. The network compresses the reference grid by reproducing most of its values, while the original values are stored only at points where the neural prediction does not reach the required accuracy. In this way, the neural model captures the bulk of the grid, with a sparse table covering the remaining difficult points. For the GS09-based dense grid studied here, only $0.694%$ of the active flavor values need to be stored in the sparse table. Compared with the compressed dense grid, the hybrid method reduces the disk footprint by a factor of $10.6$ , peak memory use by a factor of $31.6$ , and initialization time by about a factor of $10.6$ . At the same time, its evaluation throughput reaches about $85%$ of the dense-grid rate. The method is implemented natively in C++ within PDFxTMDLib and requires neither Python nor PyTorch at runtime. The hybrid scheme therefore offers much lower memory and startup costs, with only a modest reduction in evaluation speed.
hep-phhep-th0 citations
12
From CMB to LHC: A hybrid inflation model with gauged scale symmetry
Jinger Wu🇨🇳 · Mei Huang🇨🇳 · Qi-Shu Yan🇨🇳 · He-Xu Zhang🇨🇳
We propose a hybrid inflation model based on gauged scale symmetry, in which an axion-like field drives inflation while the Standard Model Higgs serves as the waterfall field. During slow-roll inflation, the Higgs is trapped in the electroweak-symmetric vacuum. When the inflaton reaches a critical value, the Higgs acquires a nonzero vacuum expectation value and and triggers electroweak symmetry breaking (EWSB) through the waterfall dynamics. We identify viable parameter regions that simultaneously accommodate current cosmic microwave background observations and Higgs data from the Large Hadron Collider. The relaxation mechanism connects the inflationary and electroweak scales by reducing the large vacuum-energy contribution required during inflation. Our framework thus provides a dynamical connection between inflation and EWSB.
hep-phastro-ph.CO0 citations
13
Chiral symmetry breaking for large "Nf" and the properties of the "rho" meson near the conformal window
Aftab Ahmad🇵🇰 · Samreen Fatima🇵🇰 · Muhammad Shahbaz🇵🇰 · Marco Antonio Bedolla🇲🇽 · Alfredo Raya🇲🇽 · Muhammad Imran🇵🇰
We study how the ground-state properties of the rho meson respond when the number of light-quark flavors N_f is driven towards the conformal window. The interaction is a symmetry-preserving, confining vector--vector contact interaction whose effective coupling carries a flavor dependence designed to encode the screening produced by fermion loops in the deep infrared. That interaction feeds the Schwinger--Dyson equation for the dressed-quark propagator and the homogeneous Bethe--Salpeter equation in the rainbow-ladder truncation, regularized in the Schwinger proper-time scheme so that quark production thresholds are absent while chiral symmetry remains broken. Raising N_f weakens the coupling, suppresses the dynamically generated mass and restores chiral symmetry together with deconfinement at a critical flavor number N^{c}_{f}. The vector channel responds differently from the pseudoscalar one. Because the $ρ$ is not a Goldstone boson, its mass is not protected by the symmetry that is being restored, and it simply follows the shrinking constituent scale, while the canonically normalized amplitude E_rho and the leptonic decay constant f_rho soften along the way. In this framework the rho sits above the nominal q\bar{q} threshold for every flavor number examined, so the state survives only as long as confinement removes that threshold. Dissociation is therefore governed by the divergence of the confinement length scale rather than by a crossing of the bound-state mass, and we contrast both criteria. The three elastic electromagnetic form factors G_E, G_M and G_Q, computed in the generalized impulse approximation, flatten as N_f grows, the zero crossing of G_E migrates towards the infrared and the charge radius expands, whereas the magnitude of the quadrupole moment decreases. The rho thus becomes a larger and rounder object as the theory approaches conformality.
hep-phhep-exhep-lathep-th0 citations
14
Probe of Solar Neutrino Magnetic Moments through Spin-Flavor Precession: Resonance Structure and Antineutrino Appearance
Pouya Bakhti🇰🇷 · Sudip Jana🇮🇳 · Chui-Fan Kong🇰🇷 · Seodong Shin🇰🇷 · Seokhoon Yun🇰🇷
We investigate solar-neutrino spin--flavor precession (SFP) induced by magnetic moments in the three-active-flavor framework. For Majorana neutrinos, SFP can convert solar neutrinos into antineutrinos of different active flavors. In the Dirac case, SFP instead produces sterile right-handed states and can lead to the disappearance of active neutrinos. Using the full $6 \times 6$ Hamiltonians and GS98 and AGSS09 solar profiles, we examine propagation-eigenvalue crossings at $B_{⊥} = 0$ and the projected magnetic couplings between the corresponding states. For normal mass ordering and $1 \leq E_{ν} / MeV \leq 20$ , we confirm the absence of finite-density Majorana crossings. A magnetically coupled Dirac crossing emerges above approximately $12 MeV$ but involves only a subdominant electron-flavor component, limiting resonant disappearance. Nonresonant Majorana conversion nevertheless offers a distinctive lepton-number-violating solar $ν ˉ_{e}$ signal, motivating our sensitivity study for the Jinping Neutrino Experiment. For a proposed $3 kt$ detector operating for five to ten years, we project a 90\% C.L. sensitivity of $P (ν_{e} \to ν ˉ_{e}) ≃ (0.85 - 1.3) \times 1 0^{- 5}$ . In the $μ_{12}$ -only benchmark, optimistic solar-core transverse magnetic fields of $B_{⊥} = 7 - 10 MG$ imply a reach of $∣ μ_{12} ∣ ≃ (2.3 - 4.1) \times 1 0^{- 13} μ_{B}$ , numerically below existing direct-scattering limits and commonly quoted stellar-cooling bounds. This could enable Jinping to provide one of the most stringent projected terrestrial sensitivities to Majorana transition magnetic moments.
hep-phastro-ph.SR0 citations
15
Interpretation of the excited $Ω_{c}$ family via mass and width in the chiral quark model
Xiao-Huang Hu🇨🇳 · Zhe-Tao Miu🇨🇳 · Yue Tan🇨🇳 · Qi Huang🇨🇳 · Ye Yan🇨🇳 · Jia-Lun Ping🇨🇳
In this work, the mass and decay properties for low-lying orbital excitations of $Ω_{c}$ baryons are investigated within the chiral quark model combined with the $^{3} P_{0}$ decay mechanism. Following the LHCb Collaboration's observations, we extend our previous study of the $Ξ_{c}^{'}$ system to the $Ω_{c}$ system, with all model parameters inherited from our earlier work. Our results consistently describe the observed $Ω_{c}$ spectrum: $Ω_{c} (3000)$ , $Ω_{c} (3050)$ , $Ω_{c} (3065)$ , and $Ω_{c} (3090)$ are well described as $λ$ -mode $1 P$ states with $J^{P} = 1/ 2^{-}$ , $3/ 2^{-}$ , $3/ 2^{-}$ , and $5/ 2^{-}$ , respectively. $Ω_{c} (3119)$ cannot be described as a pure three-quark excitation. Furthermore, $Ω_{c} (3185)$ and $Ω_{c} (3327)$ are disfavored as pure $2 S$ and $1 D$ baryon excitations, respectively, suggesting that alternative molecular or mixing scenarios merit further investigation. These results offer a coherent picture of the low-lying $Ω_{c}$ spectrum and motivate further experimental tests.
hep-ph0 citations
16
Spin-spin entanglement at high energy
Michael Fucilla🇵🇱 · Yoshitaka Hatta🇺🇸 · Bo-Wen Xiao🇨🇳
Spin correlations offer a quantum-information perspective on the partonic final states produced in high-energy scattering. We discuss the spin-density matrix of a heavy quark-antiquark pair in two complementary small- $x$ processes. In coherent diffractive production, color-singlet exchange enforces an unusually strong relation between entanglement and Bell nonlocality: a longitudinal photon creates a maximally entangled pair, whereas for a transverse photon the pair is generically both entangled and Bell nonlocal, with a model-independent point of maximal entanglement. In inclusive back-to-back production, the density matrix factorizes into a hard spin tensor and the unpolarized and linearly polarized Weizsäcker--Williams gluon distributions. The latter generates an azimuthal modulation and can increase the concurrence when the dijet relative momentum and imbalance are approximately orthogonal. Strikingly, in the saturation model considered, nonlinear effects wash out this modulation for $q_{⊥} ≲ 3 Q_{s}$ , whereas the dilute BFKL limit, in which $G_{2} / G_{0} \to 1$ , yields a maximal modulation independent of the imbalance magnitude. These results connect quantum-information observables with the Pomeron and saturation physics.
hep-phquant-ph0 citations
17
Boosted or Inelastic? Discriminating Interpretations of the LZ 248 keV Event
Satyabrata Mahapatra🇮🇳 · Partha Kumar Paul🇮🇳
The LUX-ZEPLIN experiment has reported a single nuclear recoil candidate at $E_{R} = 248 \pm 23 (stat) \pm 23 (sys)$ ~keV, disfavouring the background-only hypothesis at a global significance of $2.6 σ$ . The difficulty such an event poses is not the recoil energy itself but the absence of any accompanying excess at low energy as elastic scattering of halo dark matter yields a monotonically falling spectrum, and supplying the required momentum transfer $q ≃ 246$ ~MeV already demands $m_{χ} ≳ 79$ ~GeV. We confront the event with the two kinematically distinct mechanisms that evade this limitation, endothermic inelastic dark matter, in which a mass splitting $δ \sim O (100)$ ~keV forbids low-energy recoils and boosted dark matter, in which a light relativistic flux supplies the momentum, treating both with the same model-independent scalar--scalar, pseudoscalar--scalar and pseudoscalar--pseudoscalar effective operators. The two scenarios prove spectrally distinguishable. The inelastic spectra sit near the observed energy for every operator, placing only $6$ -- $17%$ of events below 150~keV, whereas the boosted spectra depend critically on the operator: the scalar and pseudoscalar--scalar interactions place $99%$ and $92%$ of their events below 150~keV, while the pseudoscalar--pseudoscalar interaction places $75%$ above it. Momentum dependence is thus essential to the boosted interpretation, but in the inelastic case it trades against the splitting, the preferred $δ$ decreasing monotonically from $O_{ss}$ to $O_{p s}$ to $O_{pp}$ . Because the scenarios differ across the whole high-energy window, a handful of additional events would separate them, placing the question within reach of the full LZ exposure.
hep-phastro-ph.COhep-exhep-th0 citations
18
Probing the CPT Constraint on CP Violation with $B^{+} \to π^{+} μ^{+} μ^{-}$ Decay
Ignacio Bediaga🇧🇷
The CPT theorem, combined with S-matrix unitarity, imposes nontrivial constraints on CP asymmetries in B-meson decays ~\cite{Marshak1969}. A long-standing question is whether these constraints apply in an inclusive manner---globally across all final states---or exclusively, within a final state interaction (FSI) as argued by Wolfenstein ~\cite{Wolfenstein1991}. We present the theoretical framework underlying this relationship between CP violation and the CPT theorem (CPV/CPT), deriving the CP-violating rate differences through the S-matrix formalism with final-state interactions (FSI). We propose that a precise measurement of the integrated CP asymmetry in $B^{+} \to π^{+} μ^{+} μ^{-}$ can unambiguously discriminate between the two mechanisms.
hep-ph0 citations
19
Probing $Υ (1 S)$ , $η_{b}$ and $h_{b}$ resonances in proton-lead collisions at the LHCb
Sudhansu S. Biswal🇮🇳 · Priyabrata Dash🇮🇳 · Sushree S. Mishra🇮🇳 · K. Sridhar🇮🇳
We explore the production of bottomonium states in proton--lead (pPb) collisions at the Large Hadron Collider (LHC) within the frameworks of Non-Relativistic Quantum Chromodynamics (NRQCD) and modified NRQCD (MNRQCD). In this work, we present theoretical predictions for the production cross-section, the nuclear modification factor $R_{pPb}$ and the forward-to-backward production ratio $R_{FB}$ of $Υ (1 S)$ as functions of transverse momentum and rapidity in the LHCb kinematic region. The MNRQCD framework, which incorporates perturbative soft-gluon emissions from color-octet states, provides description of quarkonium production in heavy-ion collision. Furthermore, using heavy-quark spin symmetry, we estimate the production cross-sections and expected event yields of the spin-singlet bottomonium states $η_{b}$ and $h_{b}$ within both NRQCD and MNRQCD. The predictions show significant differences between the two approaches in the integrated cross-sections and transverse momentum distributions of these resonances. Therefore, these results could provide important benchmarks for future experimental measurements at LHCb and contribute to a deeper understanding of bottomonia production and nuclear modifications in proton--lead collisions.
hep-phhep-ex0 citations
20
Dalitz decays of vector heavy quarkonia into $χ_{Q J} (1 P)$ in the Bethe-Salpeter approach
Xin-Wen Wang🇨🇳 · Wen-Yuan Ke🇨🇳 · Su-Yan Pei🇨🇳 · Tianhong Wang🇨🇳 · Qiang Li🇨🇳 · Guo-Li Wang🇨🇳
We systematically investigate the Dalitz decays of vector heavy quarkonia into $χ_{Q J} (1 P) ℓ^{+} ℓ^{-}$ ( $Q = c, b$ ; $J = 0, 1, 2$ ; $ℓ = e, μ$ ) within the instantaneous Bethe--Salpeter framework. The study covers $ψ (2 S)$ , $ψ (1 D)$ , $Υ (2 S)$ , and the so-far unobserved $Υ (1 D)$ states. For $ψ (2 S)$ electron channels, our predictions are in excellent agreement with BESIII data. We further provide the first relativistic predictions for $ψ (1 D)$ decays, with branching ratios for several electron channels reaching the $1 0^{- 5}$ level, which is accessible at current BESIII statistics. For bottomonium, $Υ (2 S) \to χ_{b J} e^{+} e^{-}$ decays yield branching fractions of $O (1 0^{- 4})$ , suggesting potential observability at Belle~II. Muonic channels are also discussed, with kinematic constraints carefully addressed. Our results establish a coherent theoretical basis for future experimental searches for heavy quarkonium Dalitz decays.
hep-phhep-ex0 citations
21
Vacuum Polarization Effects from Dark Fermion Loops in $Z^{'}$ Mediator Models and their Impact on Angular Observables in $B \to K^{*} μ^{+} μ^{-}$ Decays
Suhani Gupta🇮🇳 · Sunil Dogra🇰🇷
Rare flavour changing neutral current decays such as $B \to K^{*} μ^{+} μ^{-}$ provide sensitive probes of physics beyond the Standard Model (SM), being forbidden at tree level and arising only through loop induced processes. Angular analyses yield observables sensitive to short distance dynamics. The optimized observable $P_{5}^{'}$ shows a persistent $\sim 3 σ$ deviation from SM predictions in $q^{2} \in [1.1, 6.0] GeV^{2}$ , motivating modified Wilson coefficients. A theoretically motivated framework is investigated in which vacuum polarization of a Dirac dark fermion $χ$ modifies the propagator of a heavy $Z^{'}$ boson, inducing a momentum dependent contribution to $C_{9} (q^{2})$ . The loop corrected propagator is incorporated into the effective weak Hamiltonian for $b \to s ℓ^{+} ℓ^{-}$ . Bin averaged angular observables are computed with \texttt{flavio}, and $34, 997$ parameter points are scanned over different chiral structures of the $Z^{'}$ couplings. A $χ^{2}$ analysis identifies preferred regions that are vector dominated and chirally asymmetric. The best fit solution significantly alleviates the $P_{5}^{'}$ tension, reducing the deviation in the central $q^{2}$ bin to $0.12 σ$ , an improvement of approximately $96%$ relative to the SM. This improvement is driven by tree level $Z^{'}$ exchange, which induces $Δ C_{9} ≃ - 1.2$ , consistent with global fits and compatible with other angular observables and $B_{s} \to μ^{+} μ^{-}$ . Dark fermion vacuum polarization adds a subleading $q^{2}$ dependence to $C_{9}$ ; it does not dominate the fit, but supplies a distinctive threshold structure testable with finer binning. These results show that a $Z^{'}$ portal to a dark fermion provides a phenomenologically consistent description of the $P_{5}^{'}$ anomaly and a concrete benchmark for LHCb Run~3 analyses.
hep-ph0 citations
22
Inelastic Dark Matter at LZ from Radiative Dirac Neutrino Mass Paradigm
Pankaj Borah🇮🇳 · Satyabrata Mahapatra🇮🇳 · Newton Nath🇮🇳 · Partha Kumar Paul🇮🇳
The LUX-ZEPLIN (LZ) experiment has reported a high-energy nuclear recoil candidate, LZ230616, at $E_{R} = 248 \pm 2 3_{stat} \pm 2 3_{sys}$ keV, which is difficult to reconcile with elastic scattering of halo dark matter (DM). Endothermic inelastic scattering offers a natural explanation, but it rests on a nucleon coupling that is off-diagonal rather than diagonal. We show that this feature arises automatically within a radiative Dirac neutrino mass framework. The Standard Model is extended by three right-handed neutrinos (RHNs), a pair of vector-like neutral fermions for each generations, and a scalar sector comprising an inert doublet and a real singlet, governed by a $Z_{2} \times Z_{4}$ symmetry. The $Z_{2}$ symmetry stabilizes the DM, while the $Z_{4}$ symmetry forbids the tree-level Dirac Yukawa coupling together with all renormalizable Majorana mass terms, thereby allowing the generation of Dirac neutrino masses at the one-loop level through a softly broken scalar trilinear coupling ` $κ$ '. Since the neutral dark-sector fields can be expressed in terms of real scalar mass eigenstates, the $Z$ boson couples to them purely off-diagonally and elastic $Z$ -mediated scattering is absent identically rather than simply suppressed. The singlet--doublet mixing induced by ` $κ$ ' governs both the inelastic rate and the one-loop Dirac neutrino mass, which therefore vanish as $κ \to 0$ . We find that DM masses in the few hundred GeV to TeV range, with splittings of $O (340 - 360)$ keV, simultaneously reproduce the observed relic abundance, account for the LZ event and yield neutrino masses of the correct order, while respecting elastic direct-detection limits and all relevant theoretical and experimental constraints. A substantial part of the surviving parameter space lies within reach of DARWIN.
hep-phastro-ph.COhep-exhep-th0 citations
23
Open-channel radiation zeros and nonlinear damping of a critical-bubble internal mode
Tomohiro Inagaki🇯🇵 · Yuko Murakami🇯🇵
We study radiation and nonlinear damping of a spherically symmetric localized mode of an $O (3)$ thermal critical bubble. The leading second-harmonic radiation amplitude is determined by the overlap between a nonlinear source and a continuum scattering wave. This overlap can vanish through destructive interference as the supercooling is varied, even when the second harmonic lies above the continuum threshold. A signed-overlap scan resolves five zeros in a finite parameter interval, including three on the thinner-wall side of the two representative roots studied in detail. For these representative roots, half-line Jost--Green calculations, threshold-preserving wall deformations, and constrained radial evolution verify the cancellation and its robustness. Near a selected root, fourth-order perturbation theory predicts an $A^{2}$ displacement of the finite-amplitude radiation minimum and an $A$ -linear width of the third-harmonic-dominated region; radial evolution quantitatively tests both relations. At the selected zero, third-harmonic loss predicts $A \sim τ^{- 1/4}$ , instead of the generic $A \sim τ^{- 1/2}$ law. Measured harmonic powers and a slow-envelope reconstruction support this hierarchy. Independent center-stable shooting recovers the unprojected third-harmonic coefficient, which differs from the fixed-projector value. The results connect a tunable radiation form factor to nonlinear relaxation of an internal mode on an unstable nucleation saddle.
hep-ph0 citations
24
Did LZ see modified gravity?
Basabendu Barman🇮🇳
We investigate whether the recently reported high-energy nuclear recoil event by the LUX-ZEPLIN (LZ) collaboration can be interpreted as a signal of freeze-in dark matter (DM) in a non-standard cosmological history. We consider DM production from the Standard Model thermal bath during an era of modified expansion preceding Big Bang nucleosynthesis. Requiring consistency with the observed DM abundance, cosmological and collider constraints, we identify viable parameter regions that can accommodate the LZ event. Our results demonstrate the potential of direct detection experiments to probe non-standard cosmological histories and, more broadly, alternative theories of gravity.
hep-phastro-ph.COhep-th0 citations
25
Heavy-quark expansion at leading power for local QCD operators in gradient flow
Yun-Han Gui🇨🇳 · Xin-Qiang Li🇨🇳 · Xiang-Peng Wang🇨🇳 · Ya-Dong Yang🇨🇳
Gradient flow provides finite-flow-time QCD operators, whose matrix elements can be computed on the lattice and related to renormalized QCD operators through perturbative matching. We develop a matching framework that relates local flowed-QCD operators to the corresponding operators in heavy-quark effective theory (HQET) at leading power in the heavy-quark expansion. By combining the flowed-QCD-to-HQET matching relation with conventional QCD-to-HQET matching, we obtain a mass-dependent conversion relation between flowed-QCD operators and renormalized QCD operators. As a first application, we calculate the one-loop matching coefficients for heavy-light currents and derive the corresponding conversion coefficients. We find that heavy-quark mass effects in the matching and conversion coefficients can be numerically important when the flow scale is not much larger than the heavy-quark mass scale, highlighting the need for mass-dependent matching in precision lattice applications of gradient flow to heavy-quark observables.
hep-ph0 citations
26
Precision Sum Rule for Nucleon Isovector Polarizabilities and the Proton-Neutron Mass Difference
Xiong-Hui Cao🇨🇳 · Ling-Yun Dai🇨🇳 · Feng-Kun Guo🇨🇳
The precision of the electromagnetic proton-neutron mass difference $δ m_{QED}$ extracted from the Cottingham formula hinges on a subtraction function whose low-energy normalization $S ˉ (0)$ is fixed by the isovector combination of the proton and neutron polarizabilities, $(α_{E 1} - β_{M 1})^{p - n}$ . We derive a dispersive sum rule for this combination in terms of $s$ -channel photoabsorption cross sections and the product of $t$ -channel $γ γ \to π η / K K ˉ_{I_{t} = 1}$ and $π η / K K ˉ_{I_{t} = 1} \to N N ˉ$ amplitudes, without invoking Reggeon dominance. Combining empirical pion-photoproduction multipoles with coupled-channel Muskhelishvili--Omnès representations of the scalar-isovector $π η / K K ˉ$ amplitudes, we obtain $(α_{E 1} - β_{M 1})^{p - n} = - 2.26 (73) \times 1 0^{- 4} fm^{3}$ , fixing its sign and reducing the uncertainty by a factor of 4 compared with the previously known value. This result yields $S ˉ (0) = - 1.76 (61) GeV^{- 2}$ , leading to $δ m_{QED} = 0.7 1_{- 0.06}^{+ 0.03} MeV$ , substantially more precise than previous Cottingham determinations. The negative $S ˉ (0)$ also provides a stringent low-energy test of Reggeon dominance in the subtraction function.
hep-phhep-latnucl-exnucl-th0 citations
27
Determination of charged pion unpolarised TMDPDFs from Drell-Yan measurements
Wen-Chen Chang🇹🇼 · Chia-Yu Hsieh🇹🇼 · Chung-Wen Kao🇹🇼 · C.-J. David Lin🇹🇼 · Valentin Moos🇹🇼 · Wayne Morris🇹🇼
We present an extraction of the unpolarised transverse momentum dependent (TMD) parton distribution functions (PDFs) for the valence quarks in the pion from experimental mea- surements of the Drell-Yan process. The procedure adopted in this project relies on the framework of TMD factorisation, and the inputs of nucleon TMDPDF, pion collinear PDF, as well as the Collins-Soper kernel. The non-perturbative behaviour of the TMDPDFs is parameterised using an ansatz function that contains three unknown parameters and implements an exponential decay at large transverse distances. This work employs the most recent results in perturbation theory, and utilises a precise estimation of the nucleon TMDPDF. We perform an investigation of data used in the fit. This investigation leads to important observations regarding the effects of the kinematics and binning methods in the experimental data. Our results agree qualitatively with the previous determinations from phenomenology and a lattice computation
hep-phhep-exhep-lat0 citations
28
The $γ Z$ -box correction and its impact on parity-violating deep-inelastic scattering
Balma Duch🇪🇸 · Pere Masjuan🇪🇸 · Hubert Spiesberger🇩🇪
The $γ Z$ -box correction is an important electroweak contribution to precision parity-violation measurements, but its conventional low-energy treatment relies on an ambiguous effective quark-mass prescription. We revisit this correction using a finite-mass calculation that provides a well-defined perturbative contribution without introducing such an auxiliary scale. Applying the result to the Jefferson Lab PVDIS measurement shifts the extracted electron-quark couplings at the $1 0^{- 3}$ level. We discuss the implications of this shift for precision electroweak tests and the need for a consistent separation of perturbative and non-perturbative hadronic contributions.
hep-phnucl-th0 citations
29
Follow-up comments to searches for QCD instantons via forward proton tagging
Marek Tasevsky🇨🇿 · Valery A. Khoze🇬🇧 · Misha G. Ryskin🇷🇺
In this short text, only the main facts are reminded from the full-fledged study~\cite{Tasevsky:2022sch} and a few experimental considerations are added, reflecting developments since the publication of Ref.~\cite{Tasevsky:2022sch} in 2023.
hep-ph0 citations
30
Confronting the Higgsino Interpretation of the LZ Event with Astrophysical Uncertainties and the Solar Capture Constraints
Aditya Ghosh🇺🇸 · Ilumi Chavez🇺🇸 · Chris Kelso🇺🇸
We investigate whether astrophysical uncertainties in the local dark matter distribution can alleviate tensions between the higgsino interpretation of the LZ event and constraints from solar-capture neutrinos. We calculate the expected LZ signal over a wide range of Standard Halo Model parameters and using $N$ -body hydrodynamical simulations of Milky Way-like galaxies that include the influence of the Large Magellanic Cloud. For the Standard Halo Model, the requirement $δ ≳ 566 keV$ implies $v_{0} ≳ 240 km s^{- 1}$ , independent of the Galactic escape speed. In the simulated halo, we find that $δ = 514 keV$ is the largest mass splitting capable of producing one event in LZ's $200 keV - 300 keV$ recoil-energy range. We conclude that astrophysical uncertainties are insufficient to reconcile the higgsino interpretation of the LZ event with solar-capture neutrino constraints.
hep-ph0 citations
31
Vertexing displaced diphoton decays with recoil photons at Belle II
Zeren Simon Wang🇨🇳 · Yu Zhang🇨🇳
We propose a recoil-assisted strategy for vertexing displaced diphoton decays in $e^{+} e^{-} \to γ X$ , $X \to γ γ$ , using only one converted daughter photon. The initial state and recoil-photon momentum define the LLP flight line, whose closest approach to the converted-photon trajectory locates the decay vertex. This removes the need for a second conversion, making the conversion-related efficiency scale linearly rather than quadratically with the photon-conversion probability. For photophilic axionlike particles at Belle II, the existing $408$ fb $^{- 1}$ data set could probe previously unconstrained parameter space near $m_{a} ≃ 100$ MeV and $g_{aγ γ} ≃ 2 \times 1 0^{- 4}$ GeV $^{- 1}$ . With $50$ ab $^{- 1}$ , the reach extends to $m_{a} ≃ 310$ MeV and $g_{aγ γ} ≃ 2 \times 1 0^{- 5}$ GeV $^{- 1}$ .
hep-phhep-ex0 citations
32
Self-field of a moving string
Richard A. Battye🇬🇧 · Lukasz P. Bunio🇬🇧 · Steven J. Cotterill🇬🇧
We discuss the effectiveness of the recently proposed quantity $J_{s}$ in suppressing the contribution of a string's self-field to its spectrum, which is used in field theory simulations to track the emission of axions by decaying cosmic strings. We compute the contribution of the self-field to the spectrum of this quantity and to the usually computed spectrum of $ϕ \partial_{t} α$ for an infinitely long straight string. Although we demonstrate that the $J_{s}$ approach is a substantial improvement, we also point out that this highly symmetric model doesn't capture the full contribution of the self-field to the spectrum emitted by strings of a more complex shape, which are typical in network simulations. We then illustrate this point numerically using a simulation of a sinusoidally perturbed straight string. For this simple configuration, we managed to separate the contribution from the self-field and the radiation to the spectrum of $J_{s}$ , using the self-field subtraction method. This allows us to show that the spectrum of $J_{s}$ is still dominated by the $n = 1$ mode of the string's oscillation, which can be attributed to the self-field and is largely suppressed when the self-field is removed. We also demonstrate that this mode is predominantly sourced by variations along the direction parallel to the string, which is missing in the unconnected segment model, used by arXiv:2512.13653 to claim the effectiveness of $J_{s}$ in suppressing the self-field's contribution to the spectrum.
hep-phastro-ph.COhep-th0 citations
33
A DM candidate indicated at Fermi-LAT and LZ ? Connection with LHC and LC prospects
Alain Le-Yaouanc🇫🇷 · François Richard🇫🇷
Recently an analysis of Fermi-LAT data has claimed a significant excess of energetic photons centred around 20 GeV, in the halo of our galaxy but absent in dwarf galaxies. This excess can be interpreted as coming from dark mater (DM) objects with a mass of few 100 GeV which annihilate into hadronic jets containing photons mainly from neutral pions. This observation is independently backed up by a completely independent observation of the LUX-ZEPLIN (LZ) detector of a DM candidate in the same region of mass. To avoid contradiction with upper limits coming from dwarf galaxies, one is led to assume the presence of a spin 2 resonance coupled to these objects, which explains this difference as due to different speed distributions in the two regions. This work recalls that LHC data indicate a tower of Kaluza Klein graviton resonances. This solution is at variance with a SUSY interpretation of DM and therefore does not necessary call for a 1.1 TeV Higgsino, as often proposed. If these KK resonances are coupled to e+e-, as indicated by LHC data, an e+e- collider could observe these DM objects. LHC could confirm our KK graviton interpretation and, eventually, detect the DM particles. This would allow to define de energy needed at a future e+e- collider.
hep-phhep-ex0 citations
34
Probing Neutrino-Energy Reconstruction with New Superscaling-Based Observables
Lounès Amziane🇨🇭 · Soniya Samani🇨🇭 · Lorenzo Giannessi🇨🇭 · Federico Sánchez🇨🇭
In this study, we explore the superscaling variable $ψ^{'}$ within the context of neutrino-nucleus charged-current quasielastic interactions. Building on the neutrino-oriented definition of the superscaling variable $ψ^{'}$ , we reparametrize it in terms of the neutrino-energy reconstruction bias, thereby establishing a direct conceptual and analytical connection between the superscaling formalism and neutrino-energy reconstruction. This approach allows the hadronic part of the reconstructed $ψ^{'}$ to be expanded around the quasielastic point, yielding new observables that depend only on the outgoing-muon kinematics. At the same time, the resulting distributions remain sensitive to the underlying nuclear dynamics and vary across nuclear models. Among them, a newly identified quantity $L_{1}$ , constructed solely from the outgoing-muon kinematics, provides a nuclear-physics constraint on the neutrino-energy reconstruction bias. This observable largely inherits the scaling properties of $ψ^{'}$ across different neutrino fluxes and nuclear targets. The nuclear-model dependence is investigated using ND280-like $ν_{μ}$ and $ν ˉ_{μ}$ Monte Carlo samples on carbon, generated with several nuclear models implemented in NEUT, NuWro, and GENIE, while the stability across experimental conditions is tested using additional carbon- and argon-based flux-target configurations.
hep-ph0 citations
35
One-loop renormalization of the quark TMD in projectile light-cone gauge
Tolga Altinoluk🇵🇱 · Guillaume Beuf🇵🇱 · Jamal Jalilian-Marian🇺🇸 · Mirja Tevio🇫🇮
We use the background field formalism to calculate next-to-leading-order corrections to a quark transverse momentum dependent parton distribution function (TMD) in the projectile light-cone gauge, i.e. $A^{+} = 0$ for a left-moving target. We calculate the full result using the Mandelstam-Leibbrandt prescription for handling the light-cone singularity. From the one-loop renormalization of the quark TMD, we obtain the Collins-Soper-Sterman (CSS) evolution equations. The projectile light-cone gauge is widely used in calculations within the gluon saturation regime. Our work therefore opens a way to understanding the connections between the TMD and Colour Glass Condensate (CGC) approaches within the same framework.
hep-ph0 citations
36
Probing gluon saturation through inclusive hadron production in DIS
Carlisle Casuga🇫🇮 · Swaleha Mulani🇵🇱 · Heikki Mäntysaari🇫🇮
We investigate gluon saturation effects in semi-inclusive deep inelastic scattering (SIDIS) at small- $x$ within the Color Glass Condensate framework. We compute the SIDIS cross section at leading order in the dipole picture, expressing it in terms of the dipole-target scattering amplitude. We validate our framework by comparing with the charged hadron spectra measured at HERA. Our predictions for the EIC indicate that saturation effects result in significant nuclear suppression in the SIDIS cross section, and can provide complementary constraints on the initial condition for the Balitsky-Kovchegov evolution extracted from inclusive DIS data. These results demonstrate that SIDIS measurements at the EIC are sensitive to nonlinear QCD dynamics in the saturation regime.
hep-phnucl-th0 citations
37
Next-to-leading power gluon TMDs from back-to-back DIS dijets at next-to-eikonal accuracy at low x
Tolga Altinoluk🇵🇱 · Guillaume Beuf🇵🇱 · Alina Czajka🇵🇱 · Kacper Gosławski🇵🇱
We calculate next-to-leading power contributions to the gluon TMDs in DIS dijet production in the back-to-back limit at low x within the Color Glass Condensate (CGC) effective field theory at next-to-eikonal accuracy. We put a special emphasis on three-point correlation functions from CGC calculations, including their correspondence to an appropriately chosen definition of three- point TMDs within the aforementioned kinematical conditions. We also discuss importance of time ordering as well as momentum fraction space formulation of the correlators. Finally, we calculate the dijet cross section corresponding to the three-point CGC correlator as a combination of TMD functions.
hep-ph0 citations
38
Complex-energy spectrum and dissociation of heavy quarkonia in an anisotropic collisional quark-gluon plasma
Najmul Haque🇮🇳
We solve the Schrödinger equation for heavy quarkonia using the full complex potential of a momentum-anisotropic, collisional quark-gluon plasma. The real and imaginary parts of the complex eigenvalue give the in-medium binding energy and thermal width, while the corresponding eigenfunction determines the spatial distribution of the state. The noncentral anisotropic interaction is treated by expanding the potential in Legendre multipoles and solving the resulting coupled radial equations at fixed magnetic quantum number. The collision rate is tied to the running coupling, with the pinch singularity of the imaginary potential used to restrict the allowed parameter domain. Along the resulting pinch-free trajectories, the dissociation temperature of the $1 S$ charmonium and bottomonium states increases with anisotropy. The widths obtained from the full complex eigenvalue differ appreciably from first-order estimates based on the imaginary potential, while the corresponding $1 S$ eigenfunctions remain dominated by their leading $S$ -wave component. We compare the thermal widths with available lattice-QCD results and use them to illustrate a static survival probability.
hep-ph0 citations
39
Rotational effects on the chiral crossover transition in QCD matter
Nandita Padhan🇮🇳 · Kshitish Kumar Pradhan🇮🇳 · Arghya Chatterjee🇮🇳 · Raghunath Sahoo🇮🇳
We analyze the impact of rotation on the chiral crossover transition of QCD matter within the framework of a hadron resonance gas model. By extending the conventional formulation of the renormalized chiral condensate to a rotating hadronic medium, we find that rotation significantly modifies the chiral condensate and systematically suppresses the pseudocritical temperature as the angular velocity increases. The pseudocritical line in the $T - ω$ plane is examined, and the rotational dependence of the pseudocritical temperature is quantified through leading- and next-to-leading-order rotational curvature coefficients. We further investigate the combined effects of angular velocity and baryon chemical potential and find that their interplay leads to a stronger suppression of the pseudocritical temperature. Additionally, the spatial dependence of the chiral crossover transition is examined through the radial variation of the pseudocritical temperature. We find that the pseudocritical temperature decreases with increasing radial distance, indicating that the chiral crossover sets in at progressively lower temperatures as one goes away from the rotation axis.
hep-phhep-exhep-thnucl-ex+10 citations
40
Towards the new NNPDF4.1 global analysis
Felix Hekhorn
We review progress and plans towards a new global PDF analysis from the NNPDF Collaboration. This new release will be based on state-of-the-art theory calculations, and in particular will be based on exact NNLO interpolation grids, (approximate) N3LO QCD corrections to DGLAP evolution and DIS structure functions, and QED effects to DGLAP evolution. All relevant sources of experimental and theoretical uncertainties, the latter including missing higher orders and higher twists, are taken into account. As compared to NNPDF4.0, this new release includes more than 25 new datasets from HERA jets to Drell-Yan (inclusive and with extra jets), top quark, and jet production at the LHC among others. Our machine learning methodology is statistically validated by extensive closure and future tests and benefits from an improved hyperoptimization algorithm.
hep-ph
41
Generalized Parton Distributions: Phenomenology, Extraction, and Hadron Imaging
Simonetta Liuti · Zaki Panjsheeri · Kemal Tezgin
Generalized Parton Distributions (GPDs) provide a framework for investigating the correlated momentum and spatial structure of quarks and gluons in hadrons and for accessing fundamental properties such as angular momentum and the QCD energy-momentum tensor. In this review, we discuss the present status of GPD phenomenology, emphasizing the challenges involved in connecting deeply virtual exclusive measurements to the underlying partonic structure. We organize this problem in terms of two successive inverse problems: the extraction of Compton Form Factors (CFFs) from measured observables and the reconstruction of GPDs from the convolution integrals defining the CFFs. We review the theoretical description and phenomenological parametrizations of GPDs, current strategies for CFF and GPD extraction, and the role of lattice QCD, Bayesian inference, uncertainty quantification, and artificial intelligence, including neural networks and interpretable machine-learning approaches. We discuss the limitations of present determinations and the opportunities offered by the Jefferson Lab program, complementary exclusive processes, and the future Electron-Ion Collider. Finally, we consider how increasingly precise and multidimensional information, together with new statistical and AI methodologies, will transform GPD phenomenology in the emerging era of precision hadron imaging.
hep-ph
42
Extraction of genuine twist-3 distribution from data
Alexey Vladimirov
The report on an extraction of genuine twist-three parton distributions, obtained from a joint fit of the deep-inelastic scattering (DIS) structure function $g_{2}$ , its moment $d_{2}$ , and the Sivers and worm-gear-T asymmetries measured in semi-inclusive DIS (SIDIS). These four observables probe different sections of the same twist-three distributions, and thus their joint analysis makes a precision extraction of this two-variable function possible. Considering a sub-set of observables does not constrain the twist-three distribution in all its parts. Nonetheless, such consideration places a sufficient amount of restrictions to sufficiently accurately estimate eliminated observables, explicitly demonstrating the universality of twist-three distributions.
hep-ph
43
Diffraction of gravitational waves by extended dark objects
Nikita Blinov🇨🇦 · J. Leo Kim🇨🇦
Many dark sector models predict the formation of dark objects, such as solitons and dark stars, which can be searched for through their gravitational lensing of gravitational waves (GWs). Although these objects vary widely in size and compactness, most GW lensing studies have focused on point-like lenses. The finite size of an extended lens is important when it exceeds its Einstein radius. We evaluate the frequency-dependent effects on GW waveforms from extended lenses and demonstrate that they can be probed with current and future GW data. While finite-size effects can weaken the bounds on the fraction of dark matter in these objects compared to the point-like limit, current GW data provides complementary constraints to other gravitational tests for lens masses between $1 0^{2} M_{⊙}$ and $1 0^{5} M_{⊙}$ ; future LIGO-Virgo-KAGRA data and next-generation observatories will surpass their sensitivity. As expected, we find that the finite-size effects are important when the lens radius exceeds $\sim few \times 1 0^{6} R_{⊙} (M_{L} /100 M_{⊙})^{1/2}$ . Interpreting these constraints within specific models (a simple dissipative dark sector and axion stars), we show that current and future observations probe significant portions of the microphysical parameter space.
↳ astro-ph.COhep-ph0 citations
44
Dimensional reduction and thermodynamics of a non-local scalar field theory
S. Duque Cesar🇧🇷 · M. J. Neves🇧🇷
In this paper, we study the dimensional reduction of a nonlocal scalar field theory to 1+2 dimensions. This nonlocal model introduces a light mass parameter as a scale that primarily modifies the infrared regime of the theory. We constraint the external sources to a bidimensional plane to obtain the effective Green's function and propose an effective Lagrangian for the scalar field in 1+2 dimensions. Using the static propagator, we calculate the interaction energy between point-like charges in the planar space. Furthermore, we evaluate the causal and Feynman Green's functions, and discuss the unitarity of the effective planar model at tree level. Finally, we implement the Matsubara formalism to investigate the thermodynamics of the planar model. The exact thermal free energy shows the fractional degrees of freedom characteristic of kinematic confinement and imposes a strict low-temperature validity bound ( $T ≪ Λ$ ) to preserve the macroscopic thermodynamic stability.
↳ hep-thhep-ph0 citations
45
Consistent treatment of flavour-specific neutrino self-interactions in cosmology
Gabriela Barenboim🇪🇸 · Marco Drewes🇧🇪 · Isabel M. Oldengott🇧🇪
We study the impact of flavour-specific neutrino self-interactions on the CMB anisotropy spectrum and consistently take into account neutrino mixing. Starting from the neutrino quantum kinetic equations, we derive the neutrino Boltzmann hierarchies for the neutrino mass states. Our work shows that most scenarios of flavour-specific neutrino self-interactions are well approximated by a combined fluid approach. In practice, this implies that existing CMB bounds on the effective neutrino coupling are weakened by a factor $2$ for scenarios in which only two neutrino flavours interact (irrespective of which flavours). If only one neutrino flavour interacts the bounds are weaker by a factor $6$ , with the only caveat that the combined fluid approach is less reliable for only $ν_{e}$ interacting.
↳ astro-ph.COhep-ph0 citations
46
Dileptons in heavy-ion collisions
Hendrik van Hees🇩🇪
In this review we give an overview about dileptons as probes for the properties of the strongly interacting hot and dense matter created in heavy-ion collisions at various beam energies. As penetrating probes they leave the fireball unaffected from final-state interactions and thus provide a space-time-evolution weighted average of the in-medium properties of hot and dense QCD matter.
↳ nucl-thhep-ph0 citations
47
Near-thermal state and thermodynamic response of a QCD system in ultra-central heavy-ion collisions
Yu-Shan Mu🇨🇳 · Li Yan🇨🇳 · Xu-Guang Huang🇨🇳
We present a systematic framework to extract QCD thermodynamic properties at finite baryon density from ultra-central heavy-ion collisions, where the impact parameter is nearly zero and volume fluctuations are strongly suppressed. By mapping the measured multi-particle state of each event to an effective homogeneous fireball through the conservation of total energy, total entropy and net baryon number, a near-thermal state with variations is realized from event to event, which allows thermodynamic response relations to be tested. Using STAR Beam Energy Scan data on charged particle multiplicity and net proton fluctuations, we show that the thermalization condition is satisfied within uncertainties across collision energies, validating the interpretation of ultra-central events as small deviations from a thermally equilibrated state. We then generalize the response relations to finite baryon chemical potential, expressing the response coefficients in terms of the speed of sound and susceptibilities. Our results provide a baseline for using ultra-central collisions to probe the QCD equation of state and phase structure, including the search for the critical endpoint.
↳ nucl-thhep-phnucl-ex0 citations
48
Finite Asimov Sample Construction in Unbinned Neural Simulation-Based Inference
Rafael Coelho Lopes de Sa🇺🇸 · Jay Sandesara🇺🇸
Expected sensitivity calculations in frequentist analysis using neural simulation-based inference often require large simulated samples to approximate an unbinned Asimov dataset. We construct a finite weighted reference sample, for analyses based on learned density ratios, for which the generating parameters globally maximize the weighted likelihood. A toy example with five-dimensional observable space based loosely on high-energy physics models shows that an Asimov dataset consisting of as few as 256 weighted reference events closely reproduce the expected test statistic scans obtained with two million simulated reference events. The resulting test statistic distributions are also shown to agree with independent simulator-based pseudo-experiments. We note that this agreement with the simulator depends on the accuracy of the learned ratios and must be validated explicitly.
↳ physics.data-anhep-exhep-ph0 citations
49
Simulation of PBH formation in a matter-dominated universe
Chul-Moon Yoo🇯🇵 · Albert Escrivà🇯🇵 · Tomohiro Harada🇯🇵 · Kazunori Kohri🇯🇵
We investigate primordial black hole (PBH) formation during an early matter-dominated era using fully nonlinear numerical relativity. The initial condition is set by a functional form of the curvature perturbation including ellipticity, which makes the configuration triaxial. Two kinds of matter descriptions are considered: dust fluid and collisionless particles. In the dust fluid description, numerical computation crashes associated with the appearance of a singularity at which the fluid density diverges, unless the singularity is hidden well inside the apparent horizon. We found that, for the dust fluid description, to observe the horizon formation before calculations crash, the initial amplitude must be larger than the previous analytic estimation by a factor of 2. On the other hand, with the particle system description, calculations do not crash, and we may observe black hole formation after subsequent evolution of the system. Then the threshold of black hole formation is significantly smaller than the previous analytic estimation by an order of magnitude.
↳ gr-qcastro-ph.COhep-phhep-th0 citations
50
From breakfast, lunch, and dinner to the Bell-inequality tetrahedron
Francesco Giacosa🇵🇱
A simple pedagogical discussion and visualization of certain Bell inequalities is presented with the help of a system involving two \textquotedblleft twins\textquotedblright, originally discussed in 2605.03104. These twins answer identically when the same `question' is posed, here exemplified with: Did you like breakfast/lunch/dinner? In analogy, for two entangled particles at distant locations, the `twin-like' quantum state is such that the same outcome for the same measurement (i.e. spin direction) is obtained. In the space $(X, Y, Z)$ of mixed moments (i.e. $X$ refers to breakfast-lunch correlation, being $1$ for same answers and $- 1$ for opposite ones), the space of Bell local models is contained in a tetrahedron, while the quantum space is bound by an elliptope that embeds the tetrahedron. The whole no-signalling region in the $(X, Y, Z)$ space is the cube $[- 1, 1]^{3} .$ The twin scenario applies e.g. to the decay of the Higgs into fermions.
↳ quant-phhep-ph0 citations
51
Thermal modifications of the B-meson spectrum
Rachel Horohan D'Arcy🇮🇪 · Benjamin Jäger🇩🇰 · Seyong Kim🇰🇷 · Jon-Ivar Skullerud🇮🇪
A first-principles investigation of heavy-light meson behaviour in hot QCD matter is essential for the interpretation of experimental results associated with open heavy flavour productions in relativistic heavy-ion collision experiments. Using anisotropic lattice ensembles from the FASTSUM collaboration with Nf=2+1 dynamical Wilson-clover fermions at non-zero temperatures, we study the B and B_s spectra at non-zero temperature. We use relativistic light quark propagators, while the b quark propagators are computed with a non-relativistic effective theory (NRQCD). We find that above T_c, thermal effects on the B meson states are more significant than those on the B_s states. Also, our results support the dissolution of the B-meson bound states above T_c.
↳ hep-lathep-phnucl-th0 citations
52
NICER neutron stars with dark energy and dark matter: effects on the inferred equation of state
Nathan Rutherford🇺🇸 · Chanda Prescod-Weinstein🇺🇸 · Anna Watts🇳🇱
[Abridged] In this work, we compare neutron stars where dark energy or dark matter are present in the core, contrasting them against purely baryonic stars with the same central energy density. From this comparison, we find that the dark energy models are more constrained by neutron star observations than the dark matter models, suggesting that neutron stars can place strong constraints on dark energy parameters. We consider four configurations: purely baryonic neutron stars described by a piecewise polytropic (PP) equation of state (EoS), baryonic stars admixed with bosonic or fermionic asymmetric dark matter (ADM) cores, and stars with a dark energy core and baryonic shell, where the dark energy is described by the modified Chaplygin dark fluid (MCDF). Using the masses and radii of PSR J0740 $+$ 6620, PSR J0437 $-$ 4715, and PSR J0030 $+$ 0451, we employ Bayesian inference to investigate how accounting for bosonic/fermionic ADM and MCDF cores affects the inferred neutron star properties. We find that MCDF cores, more than PP and ADM admixed models, substantially broaden neutron star mass-radius and pressure-energy density posterior distributions. Moreover, the MCDF EoS parameters can be tightly constrained. While bosonic and fermionic ADM cores decrease the inferred maximum mass, their posteriors strongly coincide with those of the PP model for ADM mass-fractions $F_{χ} \leq 5%$ . These results demonstrate that current mass-radius observations cannot rule out MCDF cores, but they can constrain the MCDF parameter space to narrow regions. ADM admixed neutron stars, however, remain observationally identical to purely baryonic stars for all explored mass-fractions, even with improved mass-radius uncertainties. This suggests that mass-radius measurements alone are insufficient to detect ADM core inside neutron stars and that independent astrophysical or particle physics probes will be required.
↳ astro-ph.HEastro-ph.COastro-ph.SRhep-ph+10 citations
53
Emergent Einstein-Cartan gravity from a spinor loop
Yadikaer Maitiniyazi🇨🇳 · Shinya Matsuzaki🇨🇳 · Kin-ya Oda🇯🇵 · Yoshiki Uchida🇨🇳 · Masatoshi Yamada🇯🇵
In Einstein-Cartan spinor gravity under the irreversible vierbein postulate, only the spinor among the first-order variables has a kinetic term of its own at tree level. Any nonzero background vierbein breaks the local-Lorentz (LL) symmetry spontaneously. Our previous work showed that the spinor loop generates the kinetic and mass terms of the LL gauge field, manifesting LL as a hidden local symmetry. Here we show that the spinor loop also generates the vierbein two-point function, while respecting the background gauge invariance and satisfying the Ward-Takahashi identities of the true gauge invariance, for both the general-coordinate and LL symmetries. The scheme-independent logarithmic divergence assembles the familiar induced-gravity ingredients: a cosmological constant, an Einstein-Hilbert and a Weyl-squared term for the metric sector, and a mass and a higher-derivative kinetic term for the totally antisymmetric torsion. In the vierbein sector, this torsion is carried by the derivative of the antisymmetric part of the linear vierbein fluctuation. This part is the would-be Nambu-Goldstone boson of the spontaneously broken LL symmetry, and its couplings in the minimally coupled action are all fixed by general-coordinate and LL gauge invariance. The five induced terms form a single effective action, manifestly invariant under both symmetries, completing the vierbein sector of the hidden-local-Lorentz emergent-gravity scenario.
↳ hep-thgr-qchep-ph0 citations
54
Stability and Structural Properties of Hot Quark Stars within Perturbative QCD
Tousif Raza🇺🇸 · Tyler Gorda🇺🇸
The hypothesis of strange quark matter (SQM) and the possible existence of strange stars have been extensively investigated within the thermodynamic bag model, typically employing the free Fermi gas approximation with or without perturbative QCD corrections at zero temperature, where quark confinement is modeled by the bag pressure. In this work, based on the perturbative inclusion of quark mass effects, we develop a thermodynamically consistent equation of state (EOS) for SQM at finite temperature, incorporating perturbative corrections up to $O (α_{s})$ in the strong coupling constant $α_{s}$ while ensuring full adherence to the Maxwell relations. These corrections are essential for accurately describing hot quark stars potentially formed during core-collapse events. We present results for both fixed and running couplings, using a phenomenological model to include the breakdown of the perturbative running of $α_{s}$ at low momenta. Our results demonstrate that incorporating finite-temperature perturbative QCD corrections leads to SQM configurations that fall within the absolute stability window, with equilibrium energies per baryon lying below that of iron, the most tightly bound nucleus. Our EOS supports compact stars with masses exceeding $1.4 M_{⊙}$ (and above $2 M_{⊙}$ for some values of the bag constant), in agreement with current astrophysical constraints from pulsar and gravitational-wave observations.
↳ nucl-thastro-ph.HEhep-ph0 citations
55
Inclusive Neutral-Kaon Photoproduction on the Deuteron
Mutoharoh · Agus Salam · Terry Mart🇮🇩
We report on our study of inclusive neutral-kaon photoproduction on the deuteron, $d (γ, K^{0}) Y N$ , for photon energies between 0.9 and 1.1 GeV. The calculation is performed in the impulse approximation, with the deuteron wave function generated from the Bonn One-Boson-Exchange-Potential in $q$ -space (OBEPQ) within a non-relativistic framework, while the kinematics and the elementary operator are kept relativistic. For the elementary operator we employ a recently developed isobar model that includes high-spin nucleon and $Δ$ resonances and has been constrained by nearly 20,000 data points, and we compare its predictions systematically with those of the Kaon-Maid model. For the first time, the NKS1 and NKS2 data are subjected to a quantitative analysis within a modern elementary production framework. The New Operator provides a considerably better description of the data, whereas Kaon-Maid overestimates the measured cross section by up to a factor of four at the higher photon energies, a discrepancy that can be traced back to its unconstrained $γ n \to K^{0} Λ$ amplitude. We further show that the finite photon-energy and kaon-angle bins of the existing measurements generate a theoretical uncertainty comparable to the difference between the two models, so that a proper comparison with the data requires the calculation to be averaged over the experimental acceptance. A three-dimensional mapping of the cross section over the kaon momentum and angle reveals a narrow quasi-free ridge, accompanied by a second structure associated with the opening of the $Σ$ channels, from which we identify the kinematics most favorable for future measurements. Finally, the tensor target asymmetries are found to be far less sensitive to the elementary operator than the cross section, and therefore probe the nuclear dynamics in a way that is complementary to the cross section.
↳ nucl-thhep-phnucl-ex0 citations
56
Comment for the SCAC Facilities Subcommittee from the Division of Particles and Fields of the American Physical Society
D.S. Akerib🇺🇸 · A. De Gouvea🇺🇸 · P. Elmer🇺🇸 · S. Eno🇧🇯 · L. Fields🇺🇸 · A. Lankford · V. Martinez Outschoorn · P. Meade🇺🇸 · H. Murayama🇺🇸
The Division of Particles and Fields (DPF) of the American Physical Society would like to thank SCAC for providing an opportunity for input to the SCAC facilities subpanel. The DPF represents scientists working at U.S. Universities and DOE Laboratories on understanding fundamental particles and forces. We are focused on Discovery Physics. The subpanel has been asked to consider two proposed DPF-related projects, the DUNE Phase II Detectors and supporting infrastructure and U.S. contributions to a future Higgs Factory. In this note, we briefly describe the questions driving our field and the P5 strategic plan and other community prioritization documents that form the backbone of our comment. The following sections provide short descriptions of the two projects, highlighting information relevant to your charge, answers to your specific questions, and a description of the process that produced this note.
↳ hep-exhep-lathep-phhep-th0 citations

Affiliations

first authorsco-authorsvia INSPIRE