HEP Phenomenology·hep-ph

Tue·Aug 4, 2026Tuesday·August 4, 2026

52 papers—35 primary·17 cross-listed

01
Testing Lepton Wave Function Factorization in $^{71} Ge$ Electron Capture
M. Cadeddu🇮🇹 · N. Cargioli🇮🇹 · M. Cau🇮🇹 · F. Dordei🇮🇹 · L. Ferro🇮🇹
Electron-capture ratios provide precision tests of atomic wave functions and of possible non-factorization effects in nuclear electron capture. By exploiting exact leptonic wave functions, we present a general framework for predicting the electron capture rates of $^{71} Ge$ . Adopting a non-factorized treatment of the transition matrix element, we investigate the interplay between the nuclear transition density, which encodes the nuclear structure contribution, and the leptonic wave functions. Using phenomenologically constrained transition densities, we quantify the impact of non-factorization effects on the capture rates. Finally, we compare our theoretical predictions for the $L / K$ , $M / K$ and $M / L$ electron capture ratios with the current experimental world averages, providing an up-to-date assessment of the theoretical and experimental status of $^{71} Ge$ electron capture.
hep-phnucl-th0 citations
02
Low-lying singly heavy baryon states based on the rigorous calculation with the relativized quark model
Zhen-Yu Li🇨🇳 · Guo-Liang Yu🇨🇳 · Zhi-Gang Wang🇨🇳 · Jian-Zhong Gu🇨🇳
In this work, the low-lying $6_{F}$ singly heavy baryon states with positive-parity are studied in detail in the framework of the relativized quark model by using the improved calculation scheme which has successfully explained the fine structure of the low-lying negative-parity singly heavy baryons. The complete mass spectra of all the singly heavy baryon families obtained in the same framework and calculation scheme are systematically analyzed. The baryon states marked with (mass) $J^{P}$ are obtained by considering the mixing effect rigorously. It is found that the mixing effect in the singly heavy baryons depends on the flavor symmetry of the two light quarks and the baryon parity. The results show that the high-precision calculation can reproduce most of the data perfectly, and the statistical error between the calculated masses and the experimental data is only 6.96 MeV. This confirms the reliability of the improved calculation scheme. The rigorous calculation achieved by the two-step GEM enables us to analyze the detailed behavior of the various strong interaction components within the baryons with a high-precision and discover the truth of the ``soft QCD''. The large amount of data obtained in this work serves as the reliable references for related experimental and theoretical researches.
hep-ph0 citations
03
Extra-dimensional Origins of Chemical Potentials at the Cosmological Collider
Raman Sundrum🇺🇸 · Zhaohui Xu🇺🇸
We study the realization of the chemical potential mechanism in cosmological collider physics in a robust class of inflationary models arising from multiple higher-dimensional gauge fields. The rolling inflaton background corresponds to an electric field in the extra dimension in which charged particles are produced analogously to the Schwinger mechanism, while neutral particles can be produced through non-minimal interactions. We show that particles heavier than the inflationary Hubble scale can be created without Boltzmann suppression in both cases. In particular, charged Kaluza-Klein excitations can be created through minimal gauge interactions. We construct realistic models along these lines consistent with both theoretical and experimental constraints.
hep-phastro-ph.CO0 citations
04
Ubiquitous Corotation of Dark Matter Halos: Implications for Direct Detection
Dylan Folsom🇺🇸 · Carlos Blanco🇺🇸 · Mariangela Lisanti🇺🇸 · Mark Vogelsberger🇺🇸
Cosmological simulations have recently begun to quantify the halo-to-halo variance in the phase-space distribution of dark matter around the Sun. We use a sample of nearly one hundred Milky Way-like galaxies from the TNG50 simulation to determine what aspects of this variance control the predictions for dark matter direct detection. Contrary to the isotropy assumed in the standard halo model, we find the dark matter median azimuthal velocity is nonzero and preferentially corotating, i.e., in the direction of the baryonic disk's rotation, ranging from 6-70 km/s (16th-84th percentile). This corotation suppresses predicted scattering rates in laboratory experiments searching for dark matter lighter than 50 GeV and significantly affects the expected daily modulation amplitude for directional detectors. In particular, this induces a 21% uncertainty on the upper limit of the dark matter-nucleon interaction cross section at peak sensitivity for a typical isotropic ton-scale experiment. This uncertainty is not irreducible, however: it is strongly correlated with the rotational velocity. If studies of the Milky Way's formation history determine the rotation speed, this astrophysical uncertainty is reduced to 7%.
hep-phastro-ph.COastro-ph.GA1 citation
05
The flavour of SU(15) composite quarks and leptons
Benoît Assi🇺🇸 · Ryan Plestid🇨🇭 · Amartya Sengupta🇺🇸 · Jure Zupan🇺🇸
We study the flavour structure of an $S U (15)_{p}$ confining chiral gauge theory in which the Standard Model (SM) quarks, leptons, and Higgs emerge as composite bound states. The couplings of two scalar fields in the conjugate antisymmetric ( $105$ ) and conjugate symmetric ( $120$ ) representations of $S U (15)_{p}$ provide two $S U (4)_{F}$ flavour-breaking spurions that generate both the SM Yukawa couplings and the flavour-changing processes. The up and down Yukawa matrices are tightly-correlated due to a "right-handed isospin" symmetry, which predicts a trivial CKM matrix in the absence of spontaneous symmetry breaking. The lepton Yukawas are correlated with the quarks due to a common source of flavour spurions. With a judicious Froggatt-Nielsen-like texture for the two flavour spurions we find that a benchmark fit with $O (1)$ non-perturbative coefficients reproduces all six quark masses, three charged lepton masses, and the CKM matrix. The same spurions mediate charged lepton flavour violation, neutral meson mixing, rare kaon decays, and induce electric dipole moments. We compare the reach on the compositeness scale $Λ_{pre}$ across these observables in the numerical benchmark and find that the electron EDM and $K^{0}$ - $K ˉ^{0}$ mixing provide the strongest sensitivity, reaching $O (1 0^{4})$ TeV, the lower end of the range probed by proton decay, while $μ \to e γ$ , $D^{0}$ - $D ˉ^{0}$ mixing, and $μ$ - $e$ conversion give complementary reach at $1 0^{2}$ - $1 0^{3}$ TeV. The projected electron EDM sensitivity extends this to $O (1 0^{6})$ TeV, beyond the reach of planned proton decay searches.
hep-phhep-exhep-th1 citation
06
Large-Field Vacuum Decay in General Multi-Scalar Theories
Giorgio Busoni🇦🇺 · Florian Goertz🇩🇪 · Navneet Krishnan🇦🇺 · Rickson Wielian🇦🇺
Many theories beyond the standard model exhibit multiple scalar particles. Such multi-scalar theories can in principle host lower-energy vacua, and thus predict that our universe has a finite lifetime due to false vacuum decay. This scenario cannot be ruled out a priori as even the standard model's electroweak vacuum has been shown to be metastable; however, for theoretical consistency, we still require that the model does not predict a lifetime much smaller than the age of the universe. The calculation of these tunneling rates at leading order for multi-scalar theories typically includes numerical approaches, or approximations which are frequently not analytically controlled. In this article we show that, in the large-field regime, a one-dimensional radial bounce always produces the exact dominant contribution to the leading order tunneling rate, with corrections being exponentially suppressed. This allows us to write simple analytical expressions to calculate the tunneling rate in multi-scalar theories, in terms of an effective quartic coupling $λ_{eff}$ . For theories with biquadratic scalar potentials, we also derive straightforward analytical expressions for $λ_{eff}$ in terms of the original theory's couplings. Finally, we provide example applications of our results to study the vacuum stability of the 2HDM+a model and the 3-3-1 model.
hep-ph0 citations
07
Determination of the $η$ - $η^{'}$ Mixing Angle from $F_{η^{(')} γ} (Q^{2})$ within the Self-consistent Light-front Quark Model
Shuai Xu🇨🇳
We study the $η$ - $η^{'}$ system in the self-consistent light-front quark model (LFQM) with the quark flavor mixing scheme, where the single mixing angle is constrained by the transition form factors (TFFs) $F_{η^{(')} γ} (Q^{2})$ . A combined $χ^{2}$ scan of the CLEO and BABAR data yields the best fit value $θ = 41. 5^{\circ}$ , in close agreement with the recent LHCb result $(41. 6_{- 1.2}^{+ 1.0})^{\circ}$ . Using this mixing angle, we calculate the decay constants, light-cone distribution amplitudes (LCDAs), Gegenbauer moments, $ξ$ -moments, transverse momentum moments, electromagnetic interaction radii and two photon decay widths of the $η$ and $η^{'}$ mesons. The predicted $a_{2}^{η}$ and $⟨ ξ^{2} ⟩_{η}$ are consistent with the latest BABAR results, and the electromagnetic interaction radii also agreeing well with the A2 and BESIII measurements. These results demonstrate that TFFs data provide strong constraints on the light-front description for the nonperturbative properties of the $η$ - $η^{'}$ system. Owing to the lack of direct experimental constraints on the real photon value $F_{η^{(')} γ} (0)$ , the predicted decay widths are somewhat lower than the experimental data, which can be further examined with future measurements.
hep-ph0 citations
08
Matter-Induced CPT Violation and Earth-Density Stratification Effects in Long-Baseline Neutrino Oscillation Experiments
Tia Pandit🇮🇳 · Bipin Singh Koranga🇮🇳 · Vivek Kumar Nautiyal🇮🇳
We present a unified analysis of two matter-potential systematics in long-baseline (LBL) neutrino oscillation experiments, treating matter-induced extrinsic CPT violation and Earth density stratification as correlated systematics within a single $χ^{2}$ framework. We study their joint impact on CP-phase reconstruction and mass-ordering dependence. Matter-induced extrinsic CPT violation produces a non-zero asymmetry $A_{μ e}^{CPT} = (P_{μ e} - P ˉ_{μ e}) / (P_{μ e} + P ˉ_{μ e})$ , computed using exact three-flavour matrix exponentiation for T2K, NO $ν$ A, DUNE, and Hyper-Kamiokande. The asymmetry ranges from 0.022 to 0.180 at the respective peak energies and differs by up to $9%$ between normal and inverted orderings. The surface $A_{μ e}^{CPT} (E, δ_{CP})$ at DUNE reveals an interplay between extrinsic CPT and intrinsic CP violation in the high- $L / E$ regime requiring joint statistical treatment. We quantify the sensitivity of $A_{μ e}^{CPT}$ to density uncertainties $ρ \to ρ (1 + ε)$ with $ε = \pm 1%, \pm 2%, \pm 5%$ , finding that a $\pm 5%$ uncertainty induces $∣Δ A_{CPT} ∣ < 0.008$ at DUNE. Replacing the PREM profile with a constant path-averaged density yields a $δ_{CP}$ reconstruction bias below $0. 3^{\circ}$ for $L \leq 5000$ km, increasing to $17. 8^{\circ}$ at $7000$ km and $172. 2^{\circ}$ at $12000$ km. Since both effects arise from the same matter Hamiltonian, they must be modelled jointly using a Poisson log-likelihood $χ^{2}$ with nuisance-parameter pulls.
hep-ph0 citations
09
Kinetic backreaction cannot suppress axion quantum pressure
Kaleb Anderson🇺🇸 · Savvas M. Koushiappas🇺🇸
Ultralight axions from string compactifications carry non-canonical kinetic terms whose normalization is set by a coupling function that depends on an accompanying modulus field. As dark matter, such an axion forms a cold condensate whose quantum pressure resists gravitational collapse below a Jeans scale fixed by that coupling. One might hope that backreaction from the condensate's oscillations could shrink this Jeans length and thereby enhance structure growth. We show that it cannot. For any smooth, positive coupling function, the oscillation-averaged backreaction always drives the coupling to larger values, strengthening the quantum pressure and growing the Jeans length with time. We establish this no-go result analytically through an adiabatic- invariant analysis and confirm it by direct numerical integration. Kinetically coupled dark matter therefore cannot self-generate the conditions for enhanced gravitational collapse or the seeding of structure on sub-Jeans scales.
hep-phastro-ph.CO0 citations
10
Nelson-Barr Inflation
Fuminobu Takahashi🇯🇵
The Nelson-Barr mechanism solves the strong CP problem through spontaneous CP violation, but the resulting CP-conjugate vacua generically lead to stable domain walls. We propose that the Nelson-Barr scalar itself drives hilltop inflation. A CP-symmetric double-well potential for its imaginary component forms two CP-breaking valleys, with inflation proceeding along one of them. Since the lowest CP-invariant ridge is generically much higher than the energy available after inflation, transitions between the two branches are energetically inaccessible, and the domain walls cannot be regenerated after inflation. A small CP-preserving linear deformation raises the scalar spectral index of quartic hilltop inflation and yields CMB-compatible parameter regions. The Nelson-Barr sector necessarily provides a portal to visible-sector reheating. When coupled to right-handed neutrinos, it can also transmit the spontaneous CP phase to the lepton sector and, in an extension that allows a higher CP-breaking scale, even realize nonthermal leptogenesis. This establishes a unified cosmological realization of the Nelson--Barr mechanism in which the same CP-breaking dynamics solves the strong CP problem, can generate quark and lepton CP violation, drives inflation and reheating, and enables baryogenesis, while simultaneously eliminating the associated domain-wall problem.
hep-phastro-ph.COhep-th1 citation
11
Dipole-dipole scattering at high energy in the Pomeron field theory with Braun Hamiltonian and beyond
Eugene Levin🇮🇱
In this paper we find that the scattering matrix for dipole-dipole interaction in the saturation region has the form: $S_{d}^{d} z ≫ 1 exp \Lb - C_{d}^{d} z^{2} \Rb \propto \Lb S_{B K} \Rb^{4} = exp \Lb - 4 C_{B K} z^{2} \Rb$ , where $z = \bas κY + ln \Lb \frac{r ^{2}}{r ^{'2}} \Rb$ for interaction of a dipole $r$ at rapidity $Y$ with dipole $r^{'}$ at rest. $S_{B K}$ is the S-matrix for the Balitsky-Kovchegov amplitude. All constants are determined in the text. The proof is given in the same theoretical framework for both cases ( $S_{d}^{d}$ and $S_{B K}$ ): the Pomeron interaction which takes into account the Pomeron vertices in the leading $1/ N_{c}$ approximation ( $N_{c}$ is the number of colours). This result is in striking contradiction with 'rare' fluctuation approach as well as with summing the large Pomeron loops. These lead to $S_{d}^{d} \propto S_{B K}$ at large $z$ . In the paper we collect arguments supporting the idea that the sum of large Pomeron loops can be trusted in a wide region of energy: $Y \leq 1/ \as^{4}$ . In addition we discuss the influence of the structure of the Hamiltonian on the asymptotic behaviour of the scattering amplitudes using the exactly solvable one dimensional model as our theoretical ground.
hep-ph0 citations
12
Mass spectra of Tetraquark States from the Spinless Salpeter Equation
Pranami Baishya · Bhaskar Jyoti Hazarika🇮🇳
The mass spectrum of tetraquark states is examined using the spinless Salpeter equation alongside the Cornell potential. Analytical wave functions are derived through a variational approach, resulting in a specific mass formula for the bound states. This study investigates the mass spectra of heavy tetraquark states within a constituent diquark-antidiquark model. We employ a spinless Salpeter equation framework, incorporating the Cornell potential to describe the interaction between the diquark and antidiquark constituents. To account for relativistic effects, we utilize first-order perturbation theory to include the leading-order kinetic energy corrections arising from the expansion of the relativistic kinetic energy operator. A variational approach is adopted to determine the ground state masses, where the optimal variational parameter $β$ is found by minimizing the system's energy and then for higher states. We systematically calculate the masses of several experimentally observed and predicted tetraquark candidates, across a range of strong coupling constant values. Our results demonstrate a sensitivity of the calculated tetraquark masses to, and the model provides theoretical mass predictions that are in reasonable agreement with experimental observations for these exotic hadronic states. This work contributes to a deeper understanding of the internal structure and dynamics of heavy tetraquarks.
hep-phhep-th0 citations
13
Pion-photon transition form factor with analytic coupling
I.A. Zemlyakov🇨🇱 · I.L. Chuev🇷🇺 · A.V. Kotikov🇷🇺
We investigate the pion-photon transition form factor within the framework of analytic QCD. A comparison is performed between experimental data and perturbative QCD based on conventional and analytic versions of perturbation theory with the ``massive'' form of the twist-four contribution. We show that conventional perturbation theory fails to reproduce the data, while the analytic version demonstrates good agreement with experiment.
hep-ph1 citation
14
Complex chromoelectric polarizability of a heavy-quarkonium resonance: pole definition and channel-complete pNRQCD matching
Arkadiy I. Syamtomov🇺🇦
For a stable compact quarkonium, chromoelectric polarizability is generated by two E1 transitions through virtual color-octet states. An unstable quarkonium is instead defined by an isolated complex pole. We define its polarizability by the quadratic displacement of that pole. Combining the standard pole-residue definition of resonance properties with pNRQCD matching shows that the complete two-field vertex is normalized by the energy derivative of the full inverse propagator. Its numerator contains octet E1-E1 propagation, the field dependence of decay channels, and local hard matching terms, without double counting. The stable-state result is recovered with its standard sign and color factor. A minimal single-threshold model calibrated to the Psi(3770) pole gives, within its specified field convention, the residue factor 0.800-0.336i. This illustrates a potentially sizable normalization effect but is not a model-independent pole observable. The absolute polarizability still requires quarkonium and channel response inputs.
hep-phhep-th1 citation
15
Scalaron-driven Dark Matter during Warm Inflation via UV Freeze--in
F. Millo🇫🇷
We investigate the production of Dark Matter (DM) within the warm Higgs--Starobinsky (HS) inflation. By adopting the ultraviolet (UV) freeze--in mechanism -- where the DM number density is initially negligible but is populated over time through non-renormalizable interactions of defined mass dimensions -- we find that the DM production within the HS potential has a characteristic timing. For both DM masses, $m_{χ} = 1$ MeV and $m_{χ} = 100$ GeV, the yield of DM occurs close to the termination of inflation and its transition to the radiation dominated (RD) era. The present--day DM relic abundance is generated for both DM masses with non-renormalizable operators of mass dimension $D = {8, 9}$ within strong dissipation regimes. The obtained results suggest that the form of the HS potential and the associated scalaron dynamics favor UV freeze--in DM production as the scalaron approaches the minimum of the potential, where energy transfer to the thermal bath becomes particularly efficient. This distinctive transition behavior differentiates the HS model from other inflationary models and advances our understanding of DM production.
hep-phastro-ph.HEhep-thEPJC(2026)·0 citations
16
Misconceptions About the Physics of the QCD Trace Anomaly from Renormalization in a Reducible Basis
Chen Yang🇺🇸
The QCD trace anomaly is a well-established textbook result in quantum field theory with several prominent features: (1) it arises from the quantum breaking of scale symmetry at ultraviolet (UV) scales, yet is independent of the particular UV regulator used, whether lattice or dimensional regularization; (2) although it is nominally proportional to ( $O (α_{s})$ ), it is free of renormalization-scheme ambiguity; and (3) it is free of UV divergences and is therefore scale independent. Unfortunately, these important features have been undermined in the recently introduced reducible-basis renormalization, leading to misunderstandings of anomaly-related nucleon physics, including the origins of nucleon mass and internal forces.
hep-phhep-latnucl-th0 citations
17
Thermal Evolution and Hydrodynamic Filtering of Pseudoscalar Dark Matter
Xiu-Fei Li🇨🇳 · Hongxin Wang🇨🇳 · Lei Wang🇨🇳
Filtered dark matter provides a mechanism for producing massive dark matter particles during a first order phase transition. The resulting abundance can be modified by plasma hydrodynamics. We investigate this effect in a complex singlet extension of the Standard Model, focusing on the deflagration regime. The entropy normalized dark matter abundance $Y_{χ}$ is calculated using both analytic and numerical methods. As the dark matter mass increases, we identify three patterns of abundance evolution before nucleation, ranging from thermal equilibrium to thermal suppression and freeze-out. For $ξ_{w} = 0.01$ , we find that shock heating increases $Y_{χ}$ by factors of approximately $4.3$ , $5.8$ , and $32$ for $m_{χ} = 1.78$ , $2.30$ , and $5.03 TeV$ , respectively. For the two lighter masses, the numerical and analytic results agree within $5%$ , and the difference is reduced to about $1%$ or less when hydrodynamic effects are included. The heaviest case requires a numerical treatment because dark matter freeze-out before nucleation. Our results show that hydrodynamic reheating can enhance $Y_{χ}$ even when dark matter has already frozen out before the phase transition. In this regime, $Y_{χ}$ is determined by the dark matter abundance established before nucleation and hydrodynamic filtering at the bubble wall.
hep-ph0 citations
18
Model analysis on the effectiveness of the HAL QCD method for hadron-hadron interactions
Takayasu Sekihara🇯🇵 · Kei Fujiwara🇯🇵
The HAL QCD method has been one of the powerful tools to extract hadron-hadron interactions directly from lattice QCD simulation data. In this paper, we aim at examining the effectiveness of the HAL QCD method by deriving a formula to calculate quantities in the HAL QCD method, such as the so-called R-correlators and HAL QCD local potentials, from the hadron-hadron scattering amplitudes within effective models. In this framework, we can judge whether the HAL QCD local potential, evaluated in the present formula, reproduces the properties of the original hadron-hadron interaction or not via the scattering amplitude, which is a solution of the Lippmann--Schwinger equation with the original hadron-hadron interaction as an input. In an analysis within a simple model of elastic scattering, we show that, when the original interaction is predominantly local, the HAL QCD local potentials quantitatively reproduce phase shifts of the hadron-hadron scatterings and correctly indicate the existence/absence of the bound state with its binding energy $\sim$ MeV. Lattice discretization of spacetime modifies the results only slightly. Furthermore, we consider the $K ˉ N$ potential in a bare to $K ˉ N$ transition amplitude, which shows singular behavior around the origin in the recent HAL QCD results of the lattice QCD simulation data, and discuss the cause of such singular behavior in the HAL QCD method through our model analysis of the $K ˉ N$ scattering.
hep-phhep-latnucl-th0 citations
19
A femtoscopic tale of two $C$ -parities: the $Z_{c} (3900)$ and the isovector partner of the $X (3872)$
Pan-Pan Shi🇪🇸 · Miguel Albaladejo🇪🇸 · Feng-Kun Guo🇨🇳 · Juan Nieves🇪🇸
Understanding the nature of the exotic $Z_{c} (3900)$ and $Z_{cs} (3985)$ states, and searching for the predicted isovector partner $W_{c 1}$ of the $X (3872)$ , remain central challenges in exotic-hadron spectroscopy. We investigate the femtoscopic correlation functions (CFs) of the $D^{(*) 0} D_{(s)}^{(*) -}$ systems. Since these charm-meson--antimeson pairs are not $G$ -parity eigenstates, their CFs contain contributions from both the $C$ -odd and $C$ -even sectors, providing direct access to the dynamics underlying the $Z_{c}$ , $Z_{cs}$ , and the predicted isovector exotic $W_{c 1}$ . Within a heavy-quark-spin-symmetric coupled-channel framework, we show that the $C$ -even admixture enhances the low-momentum CFs by more than $2.5 σ$ in the vicinity of their thresholds. Free from Coulomb distortions and accessible in high-multiplicity $pp$ collisions at the LHC, these channels offer the first direct femtoscopic probe of the isovector $C$ -even sector and of the elusive $W_{c 1}$ state.
hep-phhep-exnucl-exnucl-th1 citation
20
Properties of the $D_{s 0}^{*} (2317)^{\pm}$ in hot and dense nuclear matter
Tomona Kinugawa🇯🇵 · Àngels Ramos🇪🇸 · Laura Tolos🇪🇸
We investigate the properties of the $D_{s 0}^{*} (2317)^{\pm}$ in hot and dense nuclear matter using a coupled-channel molecular model built on next-to-leading-order heavy meson chiral perturbation theory. In-medium modifications to the $D_{s 0}^{*} (2317)^{+}$ stem from changes to the $D K$ channel within the coupled $D K$ - $D_{s} η$ system. As nuclear density increases, the $D_{s 0}^{*} (2317)^{+}$ quasiparticle peak shifts toward lower energies and broadens, tracking the behavior of the $D$ -meson spectral function. As for temperature effects, those are milder, with the thermal smearing of the Fermi surface and the melting of $Σ_{c} N^{- 1}$ excitations in the $D$ -meson spectral function shifting the $D_{s 0}^{*} (2317)^{+}$ peak back toward its free-space mass while narrowing it. Conversely, the behavior of the $D_{s 0}^{*} (2317)^{-}$ is governed by the $D ˉ K ˉ$ channel and its medium behavior is driven by the $K ˉ$ spectral function. With increasing temperature, the $D_{s 0}^{*} (2317)^{-}$ also approaches its free-space mass, but its width broadens before saturating at high temperatures. Incorporating explicit medium dependencies into the interaction kernel, driven by density and/or temperature variations in the pion decay constant, further shifts the $D_{s 0}^{*} (2317)^{+}$ mass lower and narrows its width with temperature. As for $D_{s 0}^{*} (2317)^{-}$ , its mass also drops with temperature but its width increases. These contrasting medium behaviors offer a promising pathway to constrain the internal structure of these exotic states.
hep-phnucl-th0 citations
21
Direct Detection of Light Self-Interacting Dark Matter via Electronic Collective Excitations
Wen-Na Yang🇨🇳 · Wu-Long Xu🇨🇳 · Wenyu Wang🇨🇳 · Ning Liu🇨🇳
Models of light dark matter often invoke a light mediator to facilitate interactions with the Standard Model. If sufficiently light, this mediator can induce long-range self-interactions among dark matter particles, offering a compelling resolution to small-scale structure anomalies. However, direct detection of light self-interacting dark matter (SIDM) remains challenging for conventional detectors. In this work, we investigate the sensitivity of searches for light SIDM accelerated by high-energy cosmic rays in silicon detectors. Leveraging the electronic collective excitations, we derive 90\% C.L. exclusion limits using public SENSEI and DAMIC-M ionization data. Our constraints can cover a portion of the light SIDM parameter space favored by galactic small-scale anomalies.
hep-ph0 citations
22
Impact of Higgs precision measurements at the LHC and FCC-ee on the spectrum of composite Higgs models
Reza Asgharzadeh Jelodar🇮🇷 · Kazem Bitaghsir Fadafan🇮🇷 · Giacomo Cacciapaglia🇫🇷
We investigate the minimal composite Higgs model based on the symmetry-breaking pattern $SU (4) \to Sp (4)$ , where electroweak symmetry breaking is governed by the vacuum alignment angle $θ$ . Through the leading-order relations $κ_{V} = cos θ$ and $m_{η} = m_{h} / sin θ$ , precision measurements of Higgs couplings are translated into direct constraints on the vacuum structure and the singlet pseudo-Nambu--Goldstone boson mass. Using the current ATLAS Run-2 measurement of $κ_{V}$ , we construct a Bayesian posterior for $θ$ , including the Jacobian associated with the transformation from $κ_{V}$ to $θ$ , and validate the results through an independent frequentist $Δ χ^{2}$ analysis. The same framework is then applied to the projected sensitivities of the High-Luminosity LHC and FCC-ee. The current data imply a conservative lower bound of approximately $440 GeV$ on the singlet mass at the $95%$ credibility level, while the projected sensitivities improve this limit to about $600 GeV$ at the HL-LHC and beyond $2 TeV$ at FCC-ee. The close agreement between the Bayesian and frequentist determinations demonstrates the robustness of the extracted constraints. These results show that future Higgs precision measurements will probe the vacuum alignment of the minimal $SU (4) / Sp (4)$ composite Higgs model with unprecedented sensitivity, placing increasingly stringent constraints on the allowed parameter space and establishing the singlet scalar as a compelling target for upcoming collider programs.
hep-phhep-exhep-th0 citations
23
The CKM sector of the exceptional-Jordan programme: finite-Dirac mass moduli, two conditional angle estimates, and the weak-to-mass bridge
Tejinder P. Singh🇮🇳
The Standard Model does not determine quark masses or the CKM matrix. In the exceptional-Jordan programme, square-root masses occupy short $Sym^{3} (3)$ chains. Compressing the symmetric-cube lift onto occupied nodes gives a root-mass operator whose square yields the proposed mass ratios, packaging that spectrum and relative left frames in one finite Dirac operator without deriving the frames. Conditional on the transport, virtual-node-amplitude, real- $(2, 3)$ and balanced-quadrature choices, the no-fit layer gives $∣ V_{u s} ∣ = 0.2371$ ( $5.3%$ high) and $∣ V_{c b} ∣ = 0.0422$ ( $0.8%$ high) at $M_{Z}$ . The relation $∣ V_{u b} ∣/∣ V_{c b} ∣ = m_{u} / m_{c}$ is a factor two low; one complex long edge is fitted. The two balanced orientations give branches $(ε, ω) = (0.002079, 288. 2^{\circ})$ and $(0.005358, 202. 2^{\circ})$ , so the former $ε$ ratio is not robust and raw $ω$ is convention-dependent. For an adopted $F_{1}$ -- $F_{2}$ family embedding, we construct an exact Peirce-changing Albert lift in $f_{4} (C)$ , reproducing conjugate up/anti-down transport and $φ_{12} = - 2 χ$ . For an adopted cyclic Majorana placement and real-linear projection, its completion has real $(e_{4}, e_{3}, e_{6})$ support while the $e_{1}$ quadrature vanishes; $J_{ℓ} = 0$ and $δ_{C P}^{ℓ} = 0$ or $π$ are compatibility results in this class. The minimal radial-quartic cyclic truncation has equal-magnitude full-rank extrema or a flat direction; a mixed Albert cubic gives stable alignment only in a chosen three-edge subspace. Six diagonal mass links plus three directed Peirce links would form a connected one-cycle nine-link graph if the Yukawa block is linear in the projected bridge. This is a candidate Arkani-Hamed et al. texture skeleton, not a derivation: family-vacuum selection, chiral projection and right-frame locking remain open.
hep-phhep-th0 citations
24
What are the consequences of independent factorization and renormalization scales?
T.C. Rogers🇺🇸 · R.M. Whitehill🇺🇸
It is common for separate factorization and renormalization scales to be discussed in connection with phenomenological applications of QCD factorization theorems. We observe that simultaneously preserving renormalization group invariance, Ward identities, and the basic sum rules in the definitions of parton densities forces these scales to be equal. The statement applies to generalized pole subtraction schemes that use dimensional regularization and to collinear factorization theorems for basic processes like deep inelastic scattering. We discuss implications for estimating the effects of scale sensitivity in phenomenological calculations, consistent extractions of Standard Model parameters alongside parton densities in global QCD analyses, and generally connecting phenomenologically extracted parton densities to first principles non-perturbative techniques like lattice QCD.
hep-phhep-thnucl-th0 citations
25
Search for active-sterile neutrino transitions using Pierre Auger Observatory data
The Pierre Auger Collaboration: A. Abdul Halim🇦🇺 · P. Abreu🇵🇹 · M. Aglietta🇮🇹 · M. Ahmed🇫🇷 · I. Allekotte🇦🇷 · K. Almeida Cheminant🇳🇱 · R. Aloisio🇮🇹 · J. Alvarez-Muñiz🇪🇸 · A. Ambrosone🇮🇹 · J. Ammerman Yebra🇪🇸 · L. Anchordoqui🇺🇸 · B. Andrada🇦🇷 and 338 other authors
We investigate the sensitivity of the Pierre Auger Observatory to physics beyond the Standard Model arising from magnetic-moment-induced transitions between active and heavy sterile neutrinos. Such dipole portal interactions can enhance neutrino-nucleon cross sections above a kinematic threshold set by the sterile neutrino mass, leading to observable modifications of neutrino detection rates at ultrahigh energies (UHE). We estimate the impact of these interactions on both down-going and Earth-skimming neutrino detection channels, the contrasting responses of which enable discrimination between an enhanced neutrino flux and a modified interaction cross section. Using the non-observation of UHE neutrino candidates, we derive neutrino-flux-dependent constraints with 90% confidence-level on the transition magnetic moment for sterile neutrino masses in the range 1 TeV-100 TeV. Under the assumed flux scenarios, the resulting flavor-independent limits extend existing bounds into previously unexplored parameter space.
hep-phastro-ph.HEhep-ex0 citations
26
Magnetic field modifications to the pion-quark vertex in the Linear Sigma Model with quarks
Alejandro Ayala🇲🇽 · Flávia Fialho🇧🇷 · Adrián Lara🇲🇽 · Ana Mizher🇧🇷 · Javier Rendón🇲🇽
We compute the modification to the quark-neutral pion vertex, induced by a constant and uniform magnetic field, using the Linear Sigma Model with quarks as a low energy effective theory of QCD. The vertex is modified even at tree-level since, due to the loss of translational invariance, the calculation should be carried out in configuration space, with the quark described by Ritus wave functions instead of plane waves. We also compute the one-loop vertex modification. These modifications are found for arbitrary Landau levels occupied by the quark. We illustrate the result for the case where the quark occupies the lowest Landau level. To check the result, we also compute the one-loop vertex modification using the Schwinger proper-time method with the quark occupying the lowest Landau level and find the same result as in the case where the Ritus formalism is used.
hep-ph1 citation
27
Jet-by-jet energy correlators as stochastic probes of the parton-to-hadron transition
Jingyu Zhang🇺🇸
Energy-energy correlators are usually reported as ensemble averages and therefore do not specify how different angular regions fluctuate together from jet to jet. We retain the binned two-point correlator for each jet and study the distribution and covariance of its angular-shell weights. In a high-statistics Pythia sample, the shell variables are sparse and strongly non-Gaussian, and their covariance contains nonzero cross-shell structure spread over many modes. Regressing each shell on five jet-level summaries leaves 84-92% of the covariance trace, while shell-wise permutation and constituent-angle shuffling do not reproduce the observed off-diagonal correlations. We then compare separately generated parton- and hadron-level samples in Pythia and Herwig. Across 24 generator-radius-momentum configurations, the hadron-level covariance trace is smaller and the average neighboring-shell correlation over 0.30 <= r/R < 1 is larger. The size and angular dependence of the change differ between the generators, and a characteristic-position analysis does not identify a common scale. Jet-by-jet EEC covariance thus provides information on the parton-to-hadron transition that is absent from the mean spectrum.
hep-phhep-ex0 citations
28
Odderon exchange in high-energy $K_{S}^{0}$ regeneration at the LHC
P. Filip🇨🇿 · M. Taševský🇨🇿 · V. A. Khoze🇬🇧 · R. Pasechnik🇸🇪 · M. G. Ryskin🇷🇺 · B. G. Zakharov🇷🇺
We revisit the possibility of detecting the Odderon exchange through high-energy neutral-kaon regeneration, focusing on the in-matter $K_{L}^{0} \to K_{S}^{0}$ conversion of $(\sim 0.2 - 2)$ ~TeV $K_{L}^{0}$ mesons originating from $pp$ collisions at $s = 13.6$ ~TeV, and on the practical constraints of realizing such a measurement in the very-forward region of an LHC interaction point. The analysis has two complementary parts. First, we reproduce the original coherent-forward-regeneration estimates for a liquid-hydrogen regenerator and extend them to realistic C, Cu and Pb regenerators of an LHC-compatible geometry, including neutral-kaon attenuation. We show that an Odderon-induced regeneration phase produces a measurable distortion of the $K^{0} \to π^{0} π^{0}$ decay-vertex distribution at TeV kaon energies, but that the survival of primary $K_{S}^{0}$ mesons from the interaction point imposes severe baseline requirements, while a competing electromagnetic $C = - 1$ (photon-exchange) amplitude limits the interpretation of the coherent mode as a clean Odderon measurement. Second, we examine non-forward (diffractive) regeneration at lower kaon energies of $0.2 - 0.8$ ~TeV, where the primary- $K_{S}^{0}$ contamination is naturally suppressed, and estimate the competing Odderon, Pomeron--Odderon-cut, $ω$ -Reggeon and photon-exchange contributions to the regeneration amplitude. We identify neutron-induced neutral-only strangeness production and inelastic Regge backgrounds as the dominant limitations, quantify the background suppression required for an observable Odderon signal, and formulate the ingredients of an active double-regenerator subtraction strategy.
hep-ph0 citations
29
Gluon condensate effects on heavy quarkonium spectral functions and thermal dissociation
Fei Wang🇨🇳 · Zi-qiang Zhang🇨🇳
We investigate how the gluon condensate modifies the thermal spectral functions and melting patterns of heavy vector mesons, specifically charmonium and bottomonium, using an improved soft-wall AdS/QCD model. The framework is extended to finite temperature via a dilaton black hole geometry that consistently incorporates the backreaction from the gluon condensate. We numerically track the evolution of spectral resonance peaks as functions of both temperature and gluon condensate strength. Our calculations reveal that increasing temperature systematically broadens and suppresses spectral peaks, signaling in-medium dissociation. In contrast, a stronger gluon condensate considerably mitigates peak broadening and enhances the spectral weight of both ground and excited states. This behavior indicates that the gluon condensate hinders thermal dissociation, thereby stabilizing heavy quarkonia within the quark-gluon plasma. These findings are consistent with existing studies and provide new holographic evidence for the stabilising role of the gluon condensate from the perspective of thermal spectral functions.
hep-phhep-th0 citations
30
Measuring the trilinear Higgs self-coupling in Higgs boson pair production at multi-TeV muon colliders
Kingman Cheung🇹🇼 · Jae Sik Lee🇰🇷 · Soojin Lee🇹🇼 · Chen Wang🇹🇼
The trilinear Higgs self-coupling determines the shape of the Higgs potential, and its measurement is a central goal of future colliders. We assess the sensitivity of multi-TeV muon colliders to the coupling modifier $κ_{3}$ in Higgs boson pair production via vector boson fusion, using the $b b ˉ b b ˉ$ final state at $s = 3$ TeV with $1$ ab $^{- 1}$ and at $10$ TeV with $10$ ab $^{- 1}$ . Events are analyzed in two complementary regions, a resolved region with four jets and a boosted region with two large-radius jets. To extract the signal from backgrounds a few orders of magnitude larger, we combine a supervised jet-to-Higgs pairing network based on the SPANet approach, topological data analysis of the event energy flow, and two dedicated classifiers, $D_{HH}$ for the signal-to-background separation and $D_{κ_{3}}$ for the $κ_{3}$ shape information. The coupling is extracted from a two-dimensional likelihood fit to the distribution of the two classifier outputs. Combining the two regions, we obtain $0.80 < κ_{3} < 1.29$ at $3$ TeV and $0.96 < κ_{3} < 1.05$ at $10$ TeV at $68%$ confidence level. The $10$ TeV determination reaches the few-percent level in this statistics-limited projection, which surpasses by a large amount the precision projected for the HL-LHC.
hep-ph1 citation
31
Thermal Leptogenesis in the BNT Model of Neutrino Mass
P. S. Bhupal Dev🇺🇸 · Srubabati Goswami🇮🇳 · Debashis Pachhar🇮🇳 · Drona Vatsyayan🇨🇦
We investigate neutrino mass and thermal leptogenesis in the Babu-Nandi-Tavartkiladze (BNT) model featuring a scalar quadruplet ( $Φ$ ) and a pair of vector-like fermion triplets ( $Σ$ ). In this framework, neutrino masses are generated via an effective dimension-7 operator $LL H H (H^{†} H) / Λ^{3}$ at the tree level and via the dimension-5 operator $LL H H /Λ$ at the one-loop level. It naturally accommodates sub-eV neutrino masses even if the new physics scale $Λ$ is $O (TeV)$ , thus making the model a compelling target for experimental searches. We explore the viability of thermal leptogenesis in this model, which is distinct from the canonical seesaw-based leptogenesis due to the presence of vector-like fermions. We find that leptogenesis is viable for $M_{Σ} ≳ 1 0^{7}$ GeV for a hierarchical spectrum of fermion triplets. However, in the quasi-degenerate regime, resonant enhancement of the $C P$ asymmetry lowers this scale down to $O (TeV)$ , reconciling successful leptogenesis with the originally motivated TeV-scale phenomenology and testability of the model at colliders.
hep-ph0 citations
32
A quality-coupling relation in chiral $U (1)_{B - L}$ axion model
Yu-Cheng Qiu🇨🇳
The quality of the QCD axion can be protected by a gauge symmetry. This work considers a gauged chiral $U (1)_{B - L}$ . The vacuum expectation values of two complex scalars break $U (1)_{B - L}$ . One linear combination of their two phase degrees of freedom is eaten by the $U (1)_{B - L}$ gauge boson, while the other becomes the QCD axion. Since the PQ symmetry is accidental, there is no ambiguity in the PQ charge assignment. High axion quality implies a large anomalous coupling between the axion and the $U (1)_{B - L}$ gauge boson (or gauged Majoron). A `quality floor', namely a minimal coupling determined by the axion quality, arises for the coupling between the axion and SM fermions, extending the parameter space of QCD axions toward improved testability.
hep-phhep-th0 citations
33
The $(2 + 1)$ -dimensional Gross-Neveu-Yukawa model at finite temperature, density, and magnetic field within the Functional Renormalization Group
Justin L.P. Mauldin🇩🇪 · Dirk H. Rischke🇩🇪
We investigate the phase diagram of the (2+1)-dimensional Gross-Neveu-Yukawa (GNY) model at finite temperature, density, and magnetic field beyond mean-field, using the Functional Renormalization Group (FRG) in the local potential approximation. Large magnetic fields result in magnetic catalysis, a dimensional reduction of the system, and enhancement of chiral symmetry breaking. We employ a hydrodynamical algorithm to solve the FRG flow equation for the effective potential, which allows for go further into the infrared region than with previously used methods. We find that the chiral condensate exhibits non-trivial behavior in various regions of the phase diagram: several first-order phase transitions and de Haas -- van Alphen oscillations at small magnetic field and large chemical potential, as well as a critical endpoint which shifts to higher temperature with increasing magnetic field.
hep-phhep-thnucl-th1 citation
34
FCC precision requests: challenges for Monte Carlos and phenomenology tools
Z. Was🇵🇱
One can define three levels of ambiguities for the accelerator experiments: worse than 0.3%, around 0.3% and better than 0.3%. I will address issues important, for the last case, when Monte Carlo programs that simultaneously account for theoretical and experimental effects are necessary. To complete efforts, simultaneous effort in many specialities over years was necessary. The monumental projects of Bryan Lynn, Robin Stuart, Dima Bardin, Wolfgang Hollik and contributions of S. Jadach in the domain of precision physics need to be mentioned, they provide theoretical foundations. Incomplete lists of methodology domains and projects, usually left into references, appendices, and private notes include: (i) Phase space--> symmetries (ii) matrix element preparation --> factorizations (iii) program and development process design (iv) testing strategies (v) user interaction (vi) software tools (vii) partners and competitors. Usually we were publishing our own projects, let me mention incomplete lists of methodology domains and projects, which were usually left aside into references, appendices, and private notes: The work started on the basis of previous efforts which can be listed following names of the programs: (i) FOWL, (ii) GENRAP, (iii) Mustraal, (iv) Koralb, (v) Lesko, (vi) Tauola, (vii) KoralZ, (viii) Lumlog, (ix) Oldbab, (x) Bhlumi, (xi) Bhwide and (xii) KKMC. I will focus on some of these points. Others, hopefully, are covered in other talks. In particular I do not need to cover exponentiation and some issues of factorization; see contributions to the proceedings by B.F.L. Ward and A. Tapadar. Developments took years and did not follow a straight line; that is why there are simplifications, biases. Also a review of literature could not be completed.
hep-phPoS(2025)·0 citations
35
Two-loop amplitude for $t t ˉ W$ production at hadron colliders in the leading colour approximation
Mattia Pozzoli🇮🇹
In this contribution I present the first exact calculation of the leading-colour two-loop QCD amplitude for the associated production of a top-anti-top pair and a W boson. I discuss strategies to address the complexity of the computation, which involves complicated analytic structures, such as nested square roots, elliptic functions, and expressions with a high degree of algebraic complexity. The final result is expressed in terms of a set of special functions, which are evaluated using the method of differential equations, and rational coefficients, evaluated via finite field techniques.
hep-ph0 citations
36
Dynamics of nucleation in thermal phase transitions
Oliver Gould🇬🇧 · Joonas Hirvonen🇬🇧 · Andrey Shkerin🇨🇦 · Sergey Sibiryakov🇨🇦
We study dynamical effects during nucleation in thermal first-order phase transitions in field theory. Focusing on the classical regime of the decay of a metastable state, we present the general formula for the thermal decay rate including the dynamical prefactor and give a recipe for its systematic evaluation. We describe the physical mechanism which reduces the actual thermal decay rate with respect to the statistical rate obtained in equilibrium theory. We also discuss the thermality conditions ensuring the existence of a steady-state thermal rate, in which case our formula is exact up to exponentially small corrections. We show that it reproduces the known results for the nucleation rate in stochastic mechanics and field theory, and allows us to unify and go beyond them. We illustrate this in real-time numerical simulations of simple field theory models. We observe significant non-perturbative contributions which can dominate the dynamical prefactor in weakly-coupled field theories at moderate exponential suppression of the decay rate. We explore the connection of these non-perturbative effects to oscillons. Notably, our numerical method requires exponentially less computing time than direct simulations of decays and is thus applicable to systems with arbitrarily strong exponential suppression. Finally, we discuss small or poorly thermalized systems when the thermality conditions are violated and the steady-state rate does not exist.
↳ hep-thcond-mat.quant-gascond-mat.softhep-lat+10 citations
37
Hadron Spectroscopy: Experimental Overview
Volker Crede🇺🇸
One of the most fascinating phenomena in nuclear and particle physics is the formation of light hadrons -- strongly interacting particles -- out of massless gluons and almost massless quarks. These particles exhibit rich excitation spectra due to their complex quark-gluon structures. Short-lived pairs of virtual quarks and antiquarks are continually formed and annihilated inside hadrons. Every physics student probably knows that the proton consists of three quarks. This statement is misleading, though. For example, the proton only shows a constant excess of three quarks versus antiquarks from the outside, and these three quarks are not even well defined. Understanding hadrons goes well beyond explaining their properties in terms of three quarks for baryons and a quark-antiquark pair for mesons. Much like atomic spectroscopy revealed the structure of atoms through discrete energy levels, hadron spectroscopy seeks the mapping of the spectrum of hadronic states and to use that information to better understand the underlying theory of the strong force -- Quantum Chromodynamics (QCD). Over the past few decades, hadron spectroscopy has entered an exciting new era with the discovery of many exotic hadrons that do not fit neatly into the traditional quark model classification of ordinary baryons and mesons. Many of the discoveries come from the heavy-flavor sector. As experimental techniques and computational methods continue to advance, hadron spectroscopy will remain a vital tool for probing the deepest layers of matter and understanding the fundamental structure of the universe.
↳ nucl-exhep-exhep-ph1 citation
38
Parton distribution functions from lattice QCD
Martha Constantinou🇺🇸 · Krzysztof Cichy🇵🇱
Parton distribution functions (PDFs) provide one of the most direct ways to describe the partonic structure of hadrons in QCD. They encode nonperturbative information about quarks, antiquarks, and gluons as functions of the partonic momentum fraction $x$ , and they connect this microscopic structure to experimentally measurable high-energy scattering processes through QCD factorization. This makes PDFs interesting to pursue with lattice QCD, which provides a first-principles formulation of the strong interaction. The challenge is that PDFs are defined through light-cone correlations, while lattice QCD is formulated in Euclidean spacetime. This chapter introduces the theoretical foundations and current status of lattice-QCD calculations of PDFs, with emphasis on modern approaches based on spatially nonlocal matrix elements. We first review the light-cone definitions of quark and gluon PDFs, their Mellin moments, and the connection to QCD factorization. We then explain how large-momentum effective theory, short-distance factorization, and the short-distance operator product expansion make it possible to relate Euclidean lattice observables to light-cone partonic structure. Particular attention is given to the elements that have improved over the last five years: renormalization of Wilson-line operators, perturbative matching, finite-momentum and finite-distance effects, reconstruction of the $x$ dependence, and systematic uncertainties. We summarize selected lattice results for proton quark PDFs, pion and kaon PDFs, gluon PDFs, and twist-3 distributions, highlighting both recent progress and remaining challenges. As will be demonstrated, lattice QCD is moving from proof-of-principle calculations toward systematically improvable determinations that can complement experimental data and global QCD analyses in mapping the partonic structure of hadrons.
↳ hep-lathep-exhep-phhep-th1 citation
39
Kerr black holes with vector dark matter hair
Fredric Hancock🇺🇸 · Helvi Witek🇺🇸
We consider a massive vector-field perturbation on a Kerr black hole background. We fix the field's density at the edge of the black hole sphere of influence to model a bath of wave cold dark matter, from which the black hole can accrete endlessly. We employ the approach of Lunin, Frolov, Krtouš, Kubizňák, and Santos to separate the equations, and solve them with a mix of analytical and numerical techniques. We find that the field forms a density spike around the black hole with profile $ρ \sim r^{- 3/2}$ , consistent with dark matter spikes studied in the literature, which is not significantly distorted by spacetime rotation, except near the black hole's ergoregion. For any nonzero spin, an additional superradiant regime appears, in which co-rotating modes extract mass and angular momentum from the black hole. We find a mass \textit{extraction} rate as high as $10 M_{⊙} / yr$ in the superradiant regime for a $1 0^{9} M_{⊙}$ black hole. For large field masses, the rate at which the black-hole mass grows behaves similarly to the Schwarzschild case, reaching $\sim 100 M_{⊙} / yr$ for a $1 0^{9} M_{⊙}$ black hole. We compare these results to their scalar-field counterparts and discuss how they mix with the superradiant instability.
↳ gr-qchep-ph0 citations
40
Gamma Rays from ALP-Photon Conversion and Inverse Compton Reprocessing in Neutron Star Magnetospheres
Federica Giacchino🇪🇸 · Conrado A. Torres🇪🇸 · Giorgio Galanti🇮🇹 · Bradley J. Kavanagh🇪🇸 · Maria A. Pérez-García🇪🇸 · Jose M. Diego🇪🇸
Exploring axion-like particle (ALP) signatures from neutron stars (NSs) in the \emph{Fermi}-LAT energy range remains largely unexplored. Neutron stars with exceptionally strong magnetic fields, such as magnetars and pulsars with magnetar-like magnetic fields, provide particularly promising environments for ALP--photon conversion. Magnetars are characterized by surface magnetic fields as large as $B_{0} \sim (1 0^{14}$ -- $1 0^{15}) G$ ; however, despite their extreme magnetic fields, no steady magnetar emission has been firmly detected in the \emph{Fermi}-LAT energy range, with high-energy activity generally associated with rare flaring episodes. In this work, we investigate ALP production in the interiors of different classes of NSs and the subsequent conversion of ALPs into photons in their magnetospheres. The ALP emissivity is determined by the stellar density and temperature $T$ , while the conversion probability is enhanced by the strong magnetic fields surrounding the star. We further account for photon propagation through the Galactic magnetic field, which can provide an additional contribution to the observable photon flux. We investigate the resulting gamma-ray signatures and assess whether ALP-induced emission from NS magnetospheres could be detectable at energies $E ≳ 100, MeV$ in the \emph{Fermi}-LAT band. In addition, we consider if the reprocessing of the magnetospheric photons through inverse Compton scattering can shift part of the emission to higher energies and provide an additional observational signature. We use the resulting fluxes to derive constraints from existing gamma-ray observations and to estimate the sensitivity of future MeV--GeV observations, taking COSI as a representative example.
↳ astro-ph.HEhep-ph0 citations
41
IR Black Hole Instabilities Trigger Species-Scale Particle Production
Luis A. Anchordoqui🇺🇸 · Alek Bedroya🇺🇸 · Dieter Lüst🇩🇪 · Houri-Christina Tarazi🇺🇸
We propose a novel UV-IR mechanism in quantum gravity in which black hole instabilities act as a bridge to the most ultraviolet sector of the theory. Specifically, we argue that when black holes reach a critical temperature associated with a light tower of states, they undergo a phase transition that sources particles near the species scale, a threshold beyond which any effective field theory of gravity fails. Using the existing numerical results, we show that production of such particles through Hawking radiation is always subdominant. We also extend our investigation to a large family of dyonic and dilatonic black holes and show how the conclusion depends on the origin of the gauge symmetry, its dilatonic coupling, and the charge under that gauge symmetry.
↳ hep-thhep-ph0 citations
42
Spectral Functions of $J / ψ$ Meson in Rotating Thermal Background from Holography
Xin-Li Sheng🇮🇹 · Jun-Xia Chen🇨🇳 · Defu Hou🇨🇳 · Hai-Cang Ren🇨🇳
We investigate the spectral functions of the $J / ψ$ meson in a rotating thermal background within the soft-wall holographic model. The global rotation is implemented through a rotating AdS-like metric, while a local inertial frame is introduced in which the vector field can be decomposed into different spin states. We solve the equations of motion of the vector field in the bulk with incoming wave condition near the horizon and compute the retarded Green function, from which we extract the invariant-mass spectral functions for $J / ψ$ . When the momentum is parallel to the rotation axis, the peak energies shift by $- Ω J_{z}$ , as expected by a coupling between rotation and angular momentum, while the widths are nearly independent to $Ω$ . When the momentum is in perpendicular direction, the spectral functions for spin- $\pm 1$ states deviate significantly from the single-peak behavior and the energy shifts depart from $- Ω J_{z}$ . The resulting triplet splittings of the spectral functions provides a holographic perspective on spin-dependent vector meson properties in rotating systems.
↳ hep-thhep-ph1 citation
43
Aspects of the quantization of non-linear electrodynamics in an uniform magnetic background
M. J. Neves🇧🇷
The canonical and path integral quantization for non-linear electrodynamics in the presence of an external electromagnetic (EM) field are proposed in this work. The EM background field is introduced expanding a general lagrangian of a generic non-linear electrodynamics around the background for small fluctuations of the propagating fields, where we consider up to the quadratic terms in the propagating fields. As consequence, we obtain an electrodynamics linearized by the presence of the external EM field. Thereby, we study the canonical quantization calculating the energy for the ground state of the linearized EM field in terms of an external magnetic field. The microcausality of the model also is discussed through the Pauli-Jordan function. We also define a generating functional for the linearized EM field, in which, in the Coulomb gauge, the Green function of the model is obtained, and we can construct the perturbative formalism like in standard quantum field theory (QFT). As application of the perturbation theory, the effective potential at one loop is calculated for the linearized EM field coupled to a complex scalar field. We apply the results in the case of the Modified Maxwell ED.
↳ hep-thhep-ph0 citations
44
Classical Black Hole Scattering to Celestial Amplitudes in Effective Theories of Gravity
Saptaswa Ghosh🇮🇳
This thesis investigates quantum field theoretic approaches to classical gravity beyond General Relativity. Using worldline effective field theory, worldline quantum field theory, and on shell scattering amplitudes, it investigates compact-object dynamics in dark-sector models, scalar tensor gravity, dynamical Chern Simons gravity, and Einstein Maxwell dilaton theory. The thesis derives a range of conservative and radiative observables, including impulses, waveforms, eikonal phases, two-body potentials, and scattering angles, while incorporating effects associated with spin, parity violation, infrared structure, and multi-loop integrals. It also constructs celestial eikonal amplitudes and analyzes their conformal data in gravitational theories beyond General Relativity. Collectively, these results broaden the application of modern quantum field theoretic techniques to gravitational dynamics and contribute to a more detailed understanding of gravity beyond the Einsteinian framework. (Detailed abstract in the thesis.)
↳ hep-thgr-qchep-ph0 citations
45
A Simple Pendulum in Schwarzschild Spacetime
Andrzej Czarnecki🇨🇦 · Andrew Czezowski
We determine the small-oscillation period of a simple pendulum in Schwarzschild spacetime. After transients decay, the displaced rope coincides with a geodesic of the induced spatial metric. This determines the radial lift of the bob to quadratic order in the angular amplitude and leads to the period measured by an observer at the bob's equilibrium position, $r = r_{2}$ , with the fulcrum at $r_{1}$ , \[ T_{(2)}=4\pi\frac{r_2^2}{c r_s}\sqrt{N_2(N_1-N_2)}, \] where $N_{i} = N (r_{i})$ and $N (r) = 1 - r_{s} / r$ is the Schwarzschild lapse. The result is therefore expressed in terms of the same function that determines clock rates and gravitational redshifts. In the Newtonian limit, we reproduce the classical result $T = 2 π L_{0} / g$ . We interpret the period close to the horizon in terms of an effective pendulum length. We compare our treatment with the coordinate-length constraint adopted in an earlier study and argue that the two problems are inequivalent away from the classical, weak-field limit.
↳ gr-qchep-phhep-thGen.Rel.Grav.(2026)·0 citations
46
Measurement of the Hubble constant with high-energy neutrinos
Gonzalo Herrera🇺🇸 · Nicholas Kamp🇺🇸 · Carlos A. Argüelles🇺🇸
Measuring distances in the Universe is one of the hardest problems in physics and astronomy. Almost every distance probe relies on photons, whose propagation across cosmic distances introduces extinction, absorption, scattering, and radiative-transfer effects. Neutrinos suffer none of these and propagate unattenuated through dust, intergalactic medium, and dense source environments alike. We introduce a new distance-ladder method for measuring the Hubble constant $H_{0}$ using high-energy astrophysical neutrinos from point sources as standardizable candles, and report its first observational realization. Using 12 X-ray-selected Seyfert galaxies for which IceCube reports significant per-source neutrino excesses in its 14-year public point-source release, we exploit the disk-corona correlation $L_{ν} = κ L_{X}^{β}$ between neutrino and X-ray luminosities to construct a neutrino distance ladder anchored by non-redshift distances to NGC 1068 (Cepheid + TRGB). We find $H_{0} = 4 9_{- 30}^{+ 40} km s^{- 1} Mp c^{- 1}$ and $β = 0.6 7_{- 0.25}^{+ 0.16}$ (68% credible intervals), with the corona slope disfavoring the calorimetric limit $β = 1$ at $\sim 2 σ$ . The result is consistent with existing $H_{0}$ determinations from Planck and SH0ES within 1 $σ$ . While the uncertainty on $H_{0}$ is large, the measurement is free of electromagnetic propagation systematics and demonstrates the viability of neutrinos as a novel cosmographical probe.
↳ astro-ph.COastro-ph.HEhep-exhep-ph0 citations
47
New constraints on modified gravity with dimension-six operators from gravitational waves
Justo López-Sarrión🇪🇸 · Carlos M. Reyes🇨🇱 · César Riquelme🇨🇱 · Marco Schreck🇧🇷
The present article deals with gravitational-wave propagation affected by higher-derivative terms that break spacetime symmetries. Two dimension-6 contributions of the gravitational Standard-Model Extension pose our starting point. A linearization of the action implies a wave equation that contains additional terms with spacetime-constant background fields. The modified dispersion relations in covariant form for gravitational waves are derived, where we distinguish between nonbirefringent and birefringent sectors. A classification of the coefficients in terms of sets with index structures resembling those of the electromagnetic fields has proven to be valuable. We constrain the nonbirefringent coefficients based on the measured arrival time difference between the gravitational wave and photons from the events GW170817 and GRB 170817A, respectively. Bounds on the birefringent coefficients result from the absence of a perceivable separation of the two modes in the event GW150914. These findings quantify the extent to which standard linearized gravity is valid based on the modifications considered.
↳ gr-qchep-phhep-th0 citations
48
Primordial Correlators from a Kaluza-Klein Graviton Continuum
Shuntaro Aoki🇯🇵
Cosmological collider signals are usually discussed for isolated massive particles, whose exchange produces characteristic logarithmic oscillations in primordial correlators. In this work, we study how this signal is modified when the exchanged states form a continuous mass spectrum. We first develop a spectral representation for inflationary correlators mediated by a continuum field. In the soft limit, the non-analytic part of the seed function is expressed as a Fourier--Laplace transform of the spectral weight with respect to logarithmic momentum variables. This representation shows that a continuum superposes clock signals with different frequencies and can dephase the sharp oscillation associated with a single massive particle. We then realize this mechanism in an RS2-like inflationary braneworld, where the inflaton is localized on a de Sitter brane in a five-dimensional AdS bulk. The tensor sector contains a localized massless graviton and a continuum of Kaluza-Klein gravitons starting at $m=3H/2$. We derive the KK wavefunctions and identify the brane spectral weight fixed by the continuum wavefunction on the brane. Applying this weight to the inflaton four-point function, we find a smooth seed function rather than a persistent logarithmic clock oscillation. This behavior follows from the fact that the continuum starts at zero clock frequency, while the KK spectral weight vanishes near threshold. Our results provide a concrete higher-dimensional example in which deviations from the standard cosmological collider signal encode the structure of a continuum high-energy spectrum.
↳ hep-thastro-ph.COgr-qchep-ph1 citation
49
Necessary and sufficient conditions of nonlinear causality in viscous anisotropic hydrodynamics
Kento Yoshida🇯🇵 · Shujun Zhao🇯🇵 · Tetsufumi Hirano🇯🇵
We derive the necessary and sufficient conditions for nonlinear causality in viscous anisotropic hydrodynamics (VAH) within the approximation that neglects small correction terms. Relativistic hydrodynamics provides a successful description of the space-time evolution of the matter produced in relativistic heavy-ion collisions, yet the earliest stage at which a hydrodynamic description becomes valid remains an open question. VAH has been proposed as an extension of conventional viscous hydrodynamics (VH) that can accommodate the large pressure anisotropies of the early-time dynamics. However, in such far-from-equilibrium regimes, the nonlinear causality of the theory is not guaranteed. By analyzing the characteristic velocities of the VAH equations of motion, we derive a set of inequalities that ensures causal signal propagation in all directions. The resulting conditions take a remarkably simple form and admit a clear physical interpretation in terms of the characteristic modes of the anisotropic medium. These results establish the regime of validity of VAH and provide a foundation for its application to the early-time dynamics of relativistic heavy-ion collisions.
↳ nucl-thhep-phnucl-ex0 citations
50
Theoretical Review of Critical Point Predictions
Maneesha Sushama Pradeep🇮🇳
This review summarizes recent theoretical progress on the QCD equation of state near the critical point and developments in the maximum entropy freeze-out framework, which provides a systematic connection between hydrodynamic fluctuations and hadronic multiplicity cumulants. We also discuss recent applications of this framework, together with advances in the dynamical evolution of critical fluctuations.
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51
Diffusion and shear viscosity coefficients of hot isospin asymmetric strange hadronic matter using a chiral SU(3) model
Amruta Mishra🇮🇳 · Shujun Zhao🇨🇳 · Tetsufumi Hirano🇯🇵
We study the diffusion and shear viscosity coefficients of hot isospin asymmetric strange hadronic matter. The effects due to the baryon density, isospin, strangeness, and temperature on the nucleons and hyperons are studied within a chiral SU(3) model. The medium modifications of the baryons arise due to interactions with the mean scalar and vector fields within the model. The thermodynamic and transport properties are studied in the hot strange hadronic matter. The diffusion matrix associated with the multiple charges (baryon number, isospin, and strangeness), as well as the coefficient of shear viscosity, are computed from the Boltzmann equation using first-order Chapman--Enskog expansion within the relaxation time approximation. There are observed to be significant effects from the isospin asymmetry as well as the strangeness of the medium on the diffusion coefficients. The coefficient of shear viscosity, $η$ is observed to have a large enhancement in the presence of finite strangeness in the medium due to additional contributions from the hyperons. The effects due to isospin asymmetry on the shear viscosity coefficient is however observed to be marginal both in nuclear and hyperonic matter. The present study can be relevant for the experimental observables of asymmetric relativistic heavy-ion collisions, e.g., in the compressed baryonic matter (CBM) experiment at the FAIR facility at GSI as well as in the future J-PARC-HI program.
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52
Effects of light-cluster degrees of freedom on collective flows in heavy-ion collisions at FOPI energies
Xin Li🇨🇳 · Si-Pei Wang🇨🇳 · Rui Wang🇨🇳 · Zhen Zhang🇨🇳 · Jie Pu🇨🇳 · Chun-Wang Ma🇨🇳 · Lie-Wen Chen🇨🇳
Within a lattice Boltzmann-Uehling-Uhlenbeck transport model coupled to a kinetic approach for light-cluster formation, we investigate the impact of explicit light-cluster degrees of freedom on collective flows in Au+Au collisions at FOPI energies with beam energies $E_{beam}$ = $120$ -- $1500 A$ MeV by using a density-, momentum-, and isospin-dependent N $5$ LO Skyrme pseudopotential. We first benchmark the kinetic approach by comparing the calculated light-cluster yields with FOPI data in central Au+Au collisions. We then analyze the collective flows of protons and light nuclei (deuterons, tritons, $^{3} He$ , and $^{4} He$ ) in mid-central collisions. For protons, calculations with and without dynamical light-cluster degrees of freedom are compared to quantify the influence of dynamical cluster formation on proton directed ( $v_{1}$ ), elliptic ( $v_{2}$ ), triangular ( $v_{3}$ ), and quadrangular ( $v_{4}$ ) flows. We find that the dynamical light-cluster effect appreciably modifies proton $v_{1}$ -- $v_{4}$ flows at $E_{beam} = 120$ -- $150 A$ MeV, remains visible at $E_{beam} = 250$ -- $400 A$ MeV, and gradually weakens at $E_{beam} ≳ 600 A$ MeV. For light nuclei, the kinetic approach captures the overall beam-energy dependence of the FOPI flow data, with better agreement for $E_{beam} \geq 400 A$ MeV. We further examine the nucleon-number scaling of $v_{2} / A$ in both model calculations and experimental data, finding that the kinetic light-cluster formation approach qualitatively reproduces the observed scaling behavior. These results highlight the importance of a dynamical treatment of light-cluster formation for interpreting collective flows in heavy-ion collisions below about $600 A$ MeV, although the clustering effects on proton flows are minor at higher collision energies.
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Affiliations

first authorsco-authorsvia INSPIRE