HEP Phenomenology·hep-ph

Thu·Sep 24, 2026Thursday·September 24, 2026

35 papers—26 primary·9 cross-listed

01
Chiral Phase Structure and In-Medium Modifications of Charmed Meson Masses within SU(4) extended Linear-Sigma Models
Nourhan M. Rfeek · Alexandra Friesen · Yuri Kalinovsky · Saleh O. Allehabi · Azzah A. Alshehri · Ashraf F. El-Sherif · Abdel Nasser Tawfik
We extend the Polyakov-loop-enhanced linear-sigma model to encompass four flavors and utilize it to analyze the light, strange, and charmed meson mass spectrum as it transitions from the vacuum into a hot and dense medium. Within the mean-field approximation, we determine the masses of scalar ( $0^{++}$ ), pseudoscalar ( $0^{-+}$ ), vector ( $1^{--}$ ), and axial-vector ( $1^{++}$ ) meson states, encompassing both open- and hidden-charm constituents, as functions of temperature $T$ and baryon chemical potential $μ_{B}$ . With parameters calibrated to the vacuum spectrum, the charm degree of freedom proves essential for an accurate description of observed masses, and charmed states acquire their in-medium modifications from the light and strange condensates that modify their valence quarks. Each species seems to undergo melting along its distinct trajectory, yet all transitions occur within a narrow band surrounding the chiral transition. The open-charm $D$ -meson functions as a precise indicator of chiral restoration: its mass increases substantially across the transition and reflects the non-strange condensate, whereas hidden-charm states remain largely unaffected and serve as reference standards for the surrounding matter. We establish that transition points from three independent measurements delineate the chiral phase boundary ( $T_{c}$ , $μ_{B}$ ), whose curvature matches lattice-QCD predictions and which persists as a crossover throughout the examined range, exhibiting no critical endpoint.
hep-ph
02
The LHC is not enough: the LZ High-Recoil Event at FCC-hh and a Muon Collider
Benedikt Maier · Michael Spannowsky
The high-energy nuclear-recoil candidate reported by LUX-ZEPLIN could point to dark matter beyond the reach of the LHC. We examine how future colliders could test this interpretation, starting with the thermal Higgsino and extending to a broad class of electroweak multiplets containing neutral and charged particles. We assume an approximately pure multiplet protected by an exact stabilizing symmetry, with dominant inelastic Z exchange and the full dark-matter abundance set by gauge-dominated thermal freeze-out, where mixing and additional interactions affecting production or freeze-out are negligible. In this setting, heavy thermal masses, rare production and invisible neutral transitions make the Higgsino's main collider obstacles generic across the class, independently of supersymmetry. Charged lifetimes vary, but the benchmark spectra studied, including radiative doublet splittings, remain beyond the projected HL-LHC reach. We show how FCC-hh and a high-energy muon collider can overcome these obstacles. Our FCC-hh estimates show sensitivity to the doublets and several larger multiplets through disappearing charged tracks and complementary channels that do not depend on the charged lifetime. Muon-collider projections cover the fermionic doublet and triplet at 10 TeV and the full fermionic family considered here at 30 TeV, subject to the stated spectrum and systematic assumptions. This connects a possible underground signal to a concrete program for testing thermal electroweak dark matter at future colliders.
hep-phhep-exhep-th
03
Precise QCD Predictions for the Scotogenic Model at Colliders
Mohammed Boukidi · Camila Ramos · Richard Ruiz
Motivated by the anticipated data rates of the high-luminosity phase of the Large Hadron Collider, we report the first predictions up to next-to-leading order in quantum chromodynamics with parton-shower matching for the production and decay of scalars and heavy neutrinos from the Scotogenic model for neutrino masses and dark matter at $s = 14$ TeV and $s = 100$ TeV. We carry out our simulations using the \texttt{FeynRules}+\texttt{MadGraph5\_aMC@NLO}+\texttt{Pythia8} pipeline. As a byproduct, we report the public release of the \texttt{SM\_Scoto} Universal \texttt{FeynRules} Object libraries for modeling the Scotogenic model in high-energy processes. We comment on prospects of observing new rare $Z$ decays at future $e^{+} e^{-}$ collider facilities as well as on the production of new particles at a multi-TeV $μ^{+} μ^{-}$ collider.
hep-phastro-ph.HEhep-exhep-th
04
High-Temperature Vacua of the Standard Model from One-Form Symmetry
Ling-Xiao Xu
We study the high-temperature vacua of the Standard Model from the perspective of generalized symmetries and the global structure of the gauge group. We analyze the one-loop effective potential for Polyakov loop holonomies, incorporating the gauge identifications induced by gauging discrete subgroups of the electric one-form symmetry. This provides a classification of physically inequivalent vacua for each gauge-group quotient. We further comment on the effects of additional center-charged matter on the residual one-form symmetry and the vacuum structure.
hep-phhep-th
05
Benchmark Dark SMEFT Scenarios from the Interplay of Flavor Physics and Dark Matter Searches
Lipika Kolay · Soumitra Nandi · Ipsita Ray
We investigate the interplay between low-energy flavor physics and dark matter (DM) phenomenology within the dimension-6 dark Standard Model Effective Field Theory (dSMEFT), featuring a fermionic DM candidate. Focusing on a minimal set of effective operators, we analyze both single- and multi-operator scenarios under current flavor and DM constraints. We show that correlated multi-operator configurations are required to simultaneously satisfy all existing bounds, leading to tightly constrained benchmark regions with implications for future collider searches. We further present representative phenomenological predictions and discuss possible ultraviolet completions of the effective framework.
hep-phhep-ex
06
The universe as a superconductor: How to search for a photon mass
Andrei Gruzinov · Anson Hook · Junwu Huang
We revisit the bounds on the photon mass when it arises from an Abelian Higgs mechanism rather than a Proca term. Because the higgs is necessarily millicharged and light, the phase of the theory (Meissner, vortex, or symmetry-restored) depends on the ambient magnetic field, so the photon mass an experiment measures depends on the environment it is performed in. We classify existing experiments by the phases in which they apply, in analogy with Type I and Type II superconductors. For Type I photon masses, magnetic fields in galaxies and the intergalactic medium can restore the symmetry everywhere, allowing a vacuum photon mass as large as $0.3 MeV$ . Regions of photon mass as large as $1 0^{- 5} eV$ could be present in the Universe, and measurement of frequency dependent optical depth can potentially reveal these regions. For Type II photon masses, we show that the strongest constraints mainly arise from the requirement that the galactic dynamo generates the observed magnetic fields, which we derive by generalizing magnetohydrodynamics to a nonzero photon mass. Since the terrestrial magnetic field restores the symmetry in much of the remaining parameter space, laboratory searches performed inside large magnetically shielded volumes, or in space, could probe photon masses invisible to any experiment on Earth. Measurements of distant light sources, in particular, fast radio bursts, also offer unique sensitivity to parameters invisible to lab experiments.
hep-phastro-ph.COastro-ph.GA
07
Towards Foundation Models on Hardware Accelerators for Particle Physics
Maya Benyas · Julia Gonski · Qibin Liu · P. Alex May · Vinicius Mikuni · Benjamin Nachman · Tanvi Wamorkar · Liangyu Wu
Bandwidth constraints require many particle physics experiments to make real-time decisions on custom hardware or firmware running simplified algorithms, unlike offline analysis, where latency is usually not a limiting factor. For example, for particle jet tagging at colliders, state-of-the-art performance is achieved by foundation models with hundreds of millions of parameters pre-trained with billions of jets. We use knowledge distillation to transfer what such models have learned into efficient networks towards deployment in hardware accelerators. The teacher is the OmniLearned foundation model fine-tuned on top quark jet tagging; the student is an attention-free Deep Sets network. We demonstrate three ways the student's performance improves: adding a message-passing layer to the Deep Sets architecture, training on the teacher's soft labels rather than on ground-truth labels alone, and distilling from a pretrained teacher rather than from the same architecture trained from scratch. In each case the gain is largest in the background rejection at low signal efficiency, the regime that is most relevant for a trigger.
hep-ph
08
Supernova Gamma-Ray Echo as an Astrophysical Near Detector for Galactic Neutrino Propagation
Garv Chauhan · Yago Porto
Core-collapse supernova neutrinos offer a unique probe of physics beyond the Standard Model over Galactic baselines. Yet even a high-statistics nearby burst may be limited by source uncertainties, especially for propagation effects that average over energy and appear only as an overall flux suppression. Inspired by near--far comparisons in terrestrial oscillation experiments, we show that next-generation MeV observations of the supernova gamma-ray echo---the delayed 511 keV signal induced by the neutrino burst in the stellar envelope---can serve as an astrophysical near detector for the emitted $ν ˉ_{e}$ fluence. Comparing this echo-inferred source fluence with the surviving flux measured at Earth gives a direct test of neutrino propagation between the stellar surface and the detector. For pseudo-Dirac neutrinos, this turns the fully averaged active--sterile oscillation regime from an unobservable source-normalization ambiguity into a measurable near--far deficit, with sensitivity for nearby progenitors to splittings $δ m^{2} ≳ 1 0^{- 18} eV^{2} (0.22 kpc / D) (E_{⋆} /15 MeV)$ . The same near--far logic also applies to other propagation-induced modifications of the observed flux, including neutrino decay and neutrino interactions with Galactic dark matter.
hep-phastro-ph.HE
09
Impact of neutral fluxes and signal significance optimization on semi-exclusive $pp \to t t ˉ$ production via deep learning training
A. Cota Rodríguez · Jesús Alberto V. Corral · J. A. Murillo Quijada
Photon flux benchmark models and recent experimental estimates of pomeron energy fluxes and structure functions are implemented in Monte Carlo simulations to assess their impact on physical observables and signal strength uncertainty for the yet-to-be-observed semi-exclusive $t t ˉ$ production in proton-proton ( $pp$ ) collisions at Large Hadron Collider (LHC) and Future Circular Collider (FCC) energies. The expected cross sections increase by factors of approximately 50 and 22 for pomeron-induced and photon-induced processes, respectively, from LHC to FCC energies. TensorFlow deep neural networks discriminate semi-exclusive processes from the non-peripheral $t t ˉ X$ background, achieving a test area under the receiver operating characteristic curve (AUC) of $0.9917 \pm 0.0002$ for the photon-induced signal. At detector level, using the CMS detector geometry at CERN, the minimum Hadronic Forward energy observable is identified as the most effective discriminator against this background. For low-pileup $pp$ data, an Asimov dataset analysis incorporating statistical uncertainties and systematic contributions from pomeron and photon schemes predicts a significance of $5 σ$ for pomeron-induced and photon-induced $t t ˉ$ production with integrated luminosities of 1 and 4.7 $fb^{- 1}$ , respectively. The systematic contributions to the total uncertainty are 25.1% and 7.6%, respectively. These results highlight the potential for experimental observation using Run 2 and Run 3 LHC data and for further studies within the LHC forward physics program.
hep-phEur. Phys. J. C 86, 228 (2026)
10
Improved $B \to K_{0}^{*} (1430)$ transition form factors at next-to-leading order in light cone sum rules
Arslan Sikandar · M. Jamil Aslam
We present an improved determination of the $B \to K_{0}^{*} (1430)$ transition form factors using light-cone sum rules (LCSR) with an expansion near the light cone. We include the one-loop radiative corrections to the twist-2 and asymptotic twist-3 distribution amplitudes of the scalar meson and perform the calculation consistently in the $MS$ scheme. It allowed us to quantify the impact of radiative corrections on the form factors for each twist. A daughter sum rule is used from the $B \to K_{0}^{*} (1430)$ LCSR to ascertain Borel mass and threshold parameter simultaneously. We find that the dominant theoretical uncertainties arise from the $K_{0}^{*} (1430)$ distribution amplitudes and its decay constant. Our results are presented in a form that facilitates the incorporation of future improvements in these nonperturbative inputs, including those from lattice QCD and experimental measurements, and can be readily extended to other scalar mesons.
hep-ph
11
Tension between MiniBooNE and MicroBooNE within a 3+1 Sterile Neutrino Framework using Simulation-Based Inference
Julia P. Woodward · Austin Schneider · Joshua Villarreal · John Hardin · Janet Conrad
The MiniBooNE low-energy excess and its subsequent exclusion by MicroBooNE provide an important test of sterile-neutrino explanations of short-baseline neutrino anomalies. Such a test is complicated by the fact that both experiments use different approaches to their analyses. In this contribution, we present a consistent approach to both experiments. We perform a joint fit of MiniBooNE and MicroBooNE data to a $3 + 1$ sterile-neutrino model omitting all data-driven factors, using MicroBooNE data from both the Booster Neutrino Beam (BNB) and Neutrinos at the Main Injector (NuMI) beamlines, and evaluate the parameter goodness-of-fit (PG) tension between the two experimental results. A rigorous frequentist treatment of both parameter fitting and PG tension is challenging. Existing methods require asymptotic assumptions known to be inaccurate for neutrino oscillation measurements or repeated likelihood optimization tasks. To this end, we use a previously developed frequentist fitting framework based on simulation-based inference (SBI) and introduce a new SBI-based method for evaluating PG tension that makes the required trial-based calibration computationally feasible. We find that the addition of MicroBooNE reduces the significance of the MiniBooNE preference for sterile-neutrino oscillations, with a trials-based preference for 3+1 remaining at $2.7 σ$ . The two experiments exhibit a $\geq 2.5 σ$ PG tension within the $3 + 1$ model.
hep-phhep-ex
12
Inverse phase transitions via dark sector chemical equilibration
Esau Cervantes · Felix Kahlhoefer · Jonas Matuszak · Santiago Rosellon
We study the cosmological evolution of the effective potential in a dark sector with a spontaneously broken Abelian gauge symmetry, populated out of equilibrium through the freeze-in mechanism. Initially dilute and in the broken phase, the dark sector is described by a temperature as well as a chemical potential that reflects the low occupancy of dark sector states. We show that the thermal corrections to the effective potential depend on both of these quantities, and that they are suppressed while the sector remains dilute, but grow as internal number-changing reactions increase the occupancy and drive the system toward chemical equilibrium. We solve the coupled evolution of the temperature and chemical potential and the resulting impact on the effective potential to show that, for sufficiently large portal couplings, chemical equilibration can evolve the effective potential across a first-order barrier and drive the dark sector toward its symmetric phase through an inverse phase transition.
hep-ph
13
Anomalous soft photon production can be understood as photon emission during hadronisation
Martin Völkl · Klaus Reygers
Several experiments reported measurements of soft photons in hadronic collisions far above the predictions from QED. This work investigates possible production during the hadronisation process. It is shown that the assumption of isotropic emission of photons during the hadronisation process leads to a consistent description of the experimental data.
hep-ph
14
Axions and the RR Lyrae Period-Luminosity Relation
Jeremy Sakstein · Djuna Croon
We investigate the impact of axions on the period-luminosity relation (PLR) of RR Lyrae stars. During the red giant branch phase, emission through the electron coupling cools the core, increasing its mass at ignition. The larger core produces more luminous horizontal-branch stars, systematically shifting the zero point of the RR Lyrae PLR toward brighter magnitudes. We model the RR Lyrae population of the globular cluster M3 using stellar evolution and pulsation calculations tailored to its age and composition, and compare the resulting synthetic $K_{s}$ -band PLR with observations. For $α_{26} \equiv 1 0^{26} g_{a e}^{2} /4 π = 0.5$ , the axion-induced shift in the predicted PLR is comparable to the current uncertainty in the absolute M3 zero-point calibration.
hep-phastro-ph.COastro-ph.GAastro-ph.SR
15
ALP photo-production in the parton and hadron cascade model PACIAE
Dai-Mei Zhou · Zhi-Lei She · Jian Cao · An-Ke Lei · Wen-Chao Zhang · Hua Zheng · Li-Lin Zhu · Yu-Liang Yan · Ben-Hao Sa
In this work, the parton and hadron cascade model PACIAE is employed to simulate the events of Au+Au collisions at $s_{N N} =$ 200 GeV within the 60-80 \% centrality interval. Based on the abundant photons in final hadronic state, the statistical-mechanics-based coalescence model DCPC is applied to phenomenologically recombine post-freeze-out photon pairs into axion-like particles (ALPs) for the first time. The coalescence probability is constrained by the branching-ratio $B_{r} (a \to γ γ) = 0.57$ under the threshold of twice of $K$ meson mass. The ALP observables including yields, transverse-momentum distributions and rapidity spectra are calculated for several benchmark ALP-mass bins. These theoretical predictions are worthy to be investigated by the experiments.
hep-ph
16
Polarization and correlation effects in $γ γ \to W^{-} W^{+}$ at Next-to-Leading-Order Electroweak Accuracy
Jun Jiang · Peng-Cheng Lu · Zongguo Si · Han Zhang · Xin-Yi Zhang
We study the next-to-leading order (NLO) electroweak (EW) corrections to the polarization and correlation of $W$ boson pairs produced through photon-photon fusion in proton-proton ultra-peripheral collisions at the LHC, with both $W$ bosons decaying leptonically. The azimuthal correlation distributions of the charged leptons, which receive no contribution from anomalous quartic gauge couplings (AQGCs) at linear order, are perturbatively stable at the 0.40\% level, whereas individual correlation coefficient $C_{2, 2}$ receives relative corrections of up to $- 33.84%$ . Some of correlation coefficients that vanish at leading order (LO) in the Standard Model but are sensitive to AQGCs acquire non-zero one-loop values of order $1 0^{- 4} - 1 0^{- 3}$ . We quantify the region of the ( $a_{0} / Λ^{2}, a_{c} / Λ^{2}$ ) plane in which these loop-induced baselines compete with the AQGC contributions and find that, while irrelevant at the current experimental sensitivity, they must be included once the correlation coefficients are measured at the per-mille level.
hep-ph
17
Dynamical gluon effects in proton transversity and off-forward parton distributions from a light-front Hamiltonian approach
Pengxiang Zhang · Jiangshan Lan · Siqi Xu · Chandan Mondal · Xingbo Zhao · James P. Vary
Building on proton light-front wave functions in the $∣ q q q ⟩$ and $∣ q q q g ⟩$ Fock sectors, obtained by diagonalizing the proton light-front Hamiltonian within the Basis Light-Front Quantization framework, we present a unified study of the proton's leading-twist transversity parton distribution functions, tensor charges, generalized tensor form factors, and chiral-odd skewed generalized parton distributions in the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi region. Our results compare reasonably with available phenomenological extractions and lattice-QCD simulations and follow similar qualitative trends.
hep-ph
18
The semileptonic decays of $Ω_{b}^{*}$ , $Σ_{b}^{*}$ and $Ξ_{b}^{' *}$ baryons
Peng Yang · Guo-Liang Yu · Zhi-Gang Wang · Jie Lu · Bin Wu
In this article, we employ the QCD sum rules basing on three-point correlation function to systematically analyze the transition form factors for the semileptonic decays of the spin $\frac{3}{2}^{+}$ bottom baryons ($\Omega_{b}^{*}$, $\Sigma_{b}^{*}$, and $\Xi_{b}^{\prime *}$) to their corresponding spin $\frac{1}{2}^{+}$ charmed partners. On the phenomenological side, we eliminate the contaminations of the baryons with negative parity and those with lower spin states. The operator product expansion is carried out up to dimension-six condensates, including the perturbative part, quark condensate $\langle \bar{q} q\rangle$, gluon condensate $\langle g_{s}^{2}GG\rangle$, mixed condensate $\langle \bar{q} g_{s}\sigma Gq\rangle$, and four-quark condensates $\langle \bar{q} q\rangle^{2}$ and $g_{s}^{2}\langle \bar{q} q\rangle^{2}$. The form factors are evaluated in the space-like region and then are fitted into the time-like physical region via a $z$ -series expansion approach. Finally, the semileptonic decay widths for $Ω_{b}^{*}$ , $Σ_{b}^{*}$ and $Ξ_{b}^{' *}$ baryons are calculated with our predicted form factors, and various polarization observables are also predicted. The predicted results in this work are compared with those predicted by other collaborations, and are expected to be useful for studying the properties of these singly heavy baryons.
hep-ph
19
Earth-density effects in long-baseline neutrino experiments in a four-flavor (3+1) sterile-neutrino framework
Bipin Singh Koranga · Aditya Pant · Pranav Kumar · Vivek Kumar Nautiyal
Earth matter effects are a leading systematic in long-baseline (LBL) determinations of the CP-violating phase delta13, and eV scale sterile neutrinos remain a phenomenologically open extension of the three-flavor paradigm motivated by short-baseline anomalies. We extend the constant density versus realistic Earth profile analysis of Ref. 1 to a four-flavor (3+1) framework, in which a fourth, mostly sterile mass eigenstate with deltam2 41 = 0.30 eV2 and active-sterile mixing angles theta14 = 8.13degree, theta24 = 5.40degree couples to the active sector both through its mixing and through an additional neutral current (NC) matter potential that acts on the active flavors but not on the sterile state. We derive an analytical, leading-order account of how the NC potential ANC enters the reconstructed delta13 bias through an effective non standard interaction like term generated by adiabatically integrating out the fast deltam241 oscillation; replace the four-shell Earth density model with the continuous, polynomial PREM profile of Dziewonski & Anderson (1981) for the layered true trajectory; and extend the baseline scan to four representative values of the sterile CP phase delta14 is 0, pi/2, pi, 3pi/2 and to a non-zero mixing angle theta34 = 5degree. Within this benchmark, the bias remains below our scan resolution for L <= 5000 km. It grows once the trajectory samples the lower mantle and core, with the sterile sector redistributing rather than uniformly amplifying or suppressing the bias across baseline, in agreement with our original finding and now traced to a specific interference mechanism identified analytically below.
hep-ph
20
CP asymmetry and visible decay in $3 + 1$ neutrino oscillations on a quantum computer
Amartya Sengupta · Sidhartha Samtani · Ani Girgvliani · Dejan Stojkovic
We use quantum simulation to study how visible neutrino decay modifies the vacuum CP asymmetry in muon-to-electron oscillations within a $3 + 1$ neutrino scenario. The decay channel preserves CP symmetry, with CP violation arising from phases in the mixing matrix. We track the energy redistribution from visible decay and distinguish how parent attenuation and daughter regeneration modify the CP asymmetry. For the reference benchmark, the regenerated contribution is $4.85 \times 1 0^{- 4}$ , approximately $46%$ of the total decay-induced shift. The full circuit for an effective two-energy model agrees with independent classical evolution. On an IBM quantum processor, we prepare the daughter state conditioned on decay and restore its physical normalization using fixed source and decay probabilities. After correction for measurement errors, the flavor-probability and coherence measurements both agree with the prediction within one standard error. Null controls test the suppression of the regenerated signal when daughter coherence or the relevant CP-sensitive mixing factor vanishes.
hep-phquant-ph
21
Sensitivity to Higgs Pseudo-Observables in ZH Production at NLO QCD
Makhlouf Chennit · Abdelkader Mohamed-Meziani
We study the sensitivity of the associated Higgs production process $pp \to Z H$ to anomalous Higgs couplings within the Effective Field Theory framework. Event samples are generated using $MadGraph5_aMC@NLO$ at $s = 13$ TeV using the UFO model HPO\_ewk\_prod\_NLO, and analyzed using a dedicated Python analysis of HepMC events. We investigate several kinematic observables and derive constraints on the EFT parameter $ϵ_{Z Z}$ using a $χ^{2}$ statistical analysis. A 95\% confidence level interval $- 0.026 < ϵ_{Z Z} < 0.383$ is obtained from the simulated data.
hep-ph
22
Response of Hellinger-distance based coherence to weak decoherence in two-flavor neutrino oscillations
Saurabh Rai · Nilakshi Das · Tejhas Kapoor
We evaluate the Hellinger-distance coherence of the two-flavor neutrino state subject to Lindblad damping of the mass-eigenstate interference term, and obtain a closed expression in terms of the flavor-basis density-matrix elements. In the two-flavor vacuum treatment with negligible wave-packet separation, the undamped state is pure, and the smallest eigenvalue of the damped state grows linearly with $ϵ = 1 - κ$ , where $κ = e^{- Γ L}$ . An expansion about the pure state then yields a nonanalytic $ϵ$ correction to the Hellinger coherence, with coefficient $K = 22 u sin 2 θ / 1 - 2 u$ , whereas the flavor-transition probability, the $l_{1}$ coherence, the concurrence, the entanglement of formation and the local quantum Fisher information all respond linearly in $ϵ$ . Using representative Daya Bay, KamLAND and MINOS working points together with a current $90%$ C.L. bound on energy-independent damping, we find fractional changes in the Hellinger coherence of $0.18%$ , $9.40%$ and $21.51%$ , against $0.0009%$ , $0.43%$ and $1.81%$ for the concurrence. The comparison concerns the response of the quantifiers to the damping parameter and carries no implication about experimental resolution. The same mechanism operates, with a different coefficient, for a correlated dephasing channel acting on the flavor coherence, where the non-Markovian regime produces damped revivals.
hep-phquant-ph
23
The topological non-Abelian string in the extended $SU (N) \otimes U (1)$ gauge sector
Zhengyang Bian · Ning Chen · Mian Guo · Saurabh K. Shukla · Junyi Wei
We study the topological non-Abelian string and its classical stability in models with two Higgs fields to achieve the symmetry breaking of $SU (N) \otimes U (1)_{X} \to SU (N - 1) \otimes U (1)_{X^{'}}$ . The topological origin is due to the global $U (1)$ symmetry and its breaking in the scalar potential. The most generic winding configurations of arbitrary integers of $(n_{1}, n_{2})$ are considered. The stability of the topological string is analyzed based on the time-dependent perturbations to the string background and numerical solutions to the coupled Helmholtz equations of the perturbed Fourier modes. We present the constraints on the stable regions for the $(n_{1}, 0)$ configuration (or equivalently the $(0, n_{2})$ configuration). For the general winding configurations of $(n_{1} \neq = 0, n_{2} \neq = 0)$ , we point out the stable regions only exist in the semilocal limit of the large mixing angle of $ϑ_{N} \to \frac{π}{2}$ .
hep-phhep-th
24
Dark Transport Erases Baryon Inhomogeneity from Supercooled Phase Transitions
Sudhakantha Girmohanta · Kohei Kamada · Yuichiro Nakai · Fumio Uchida
Supercooled phase transitions can generate observable gravitational waves, but their bubble dynamics may also imprint large spatial inhomogeneities in the baryon asymmetry. For phase transitions below the TeV scale, ordinary baryon diffusion can be too slow to erase such inhomogeneities before Big Bang Nucleosynthesis, potentially leading to stringent constraints from the observed light-element abundances. We show that this problem can be naturally avoided in darkogenesis scenarios, where the phase transition first generates an asymmetry in a dark-sector particle that is subsequently transferred to visible baryons. The dark-sector particle can travel over much larger distances than ordinary baryons before decaying, erasing the inhomogeneity before the baryon asymmetry is established. We derive the conditions for efficient erasure in both the diffusive and collisionless transport regimes and translate them into constraints on the dark-sector interactions. For a representative dark phase transition with a reheating temperature of $O (1) GeV$ , $β / H ≃ 10$ , and a dark-sector particle lifetime of $0.1 s$ , we find that the inhomogeneity is efficiently erased for a viable range of the interactions. Importantly, baryogenesis before the phase transition is challenged both by dilution from strong supercooling and by the subsequent imprinting of spatial inhomogeneities. This points toward darkogenesis associated with the phase transition as a consistent framework, in which dark-sector transport erases the inhomogeneity before it is transferred to visible baryons.
hep-phastro-ph.COhep-exhep-th
25
Twist-3 T-Even TMD Distributions in Quark Target Model
Siddhesh Padval · Anuradha Misra · Abhirup Karmakar · Deepesh Bhamre
Transverse momentum dependent parton distributions are objects that have gained substantial attention in the recent past as they are crucial for studying the 3-D structure of proton. These distributions at twist-3 are important for understanding phenomena like beam single spin asymmetries, which are observed in high-energy scattering experiments. However, due to the unavailability of direct phenomenological fits, currently one has to rely on simplified models of the proton in order to obtain these twist-3 distributions. In this work, we present the calculation of T-even twist-3 quark distributions using the quark target model.
hep-phPoS(RADCOR2025) (2026) 065
26
Analytic Methods for Perturbative Quantum Chromodynamics
Fabian Wunder
Nature, at the shortest distances accessible to contemporary colliders, is described by the Standard Model of particle physics with remarkable precision. Since the discovery of the Higgs boson in 2012, progress has shifted from finding new resonances to precision studies of established theory. Here, quantum chromodynamics (QCD), describing the interactions of quarks and gluons, plays a central role. Collider observables involving hadrons are made theoretically accessible by factorization, which separates universal long-distance hadron dynamics encoded in parton distributions from process-specific short-distance coefficients calculable in perturbation theory. This thesis develops analytic methods for perturbative QCD with applications to collider phenomenology and proton structure. A major part is devoted to angular integrals, key building blocks of phase-space integrals. Methods originally developed for Feynman integrals, including integration-by-parts identities, expansion by regions, differential equations, and dimensional shifts, are adapted to angular integrals and yield several new results. The analytic structure of one-loop integrals is also studied, with spurious branch cuts removed using single-valued polylogarithms, leading to a compact representation of coefficient functions for semi-inclusive deep-inelastic scattering. A systematic expansion in higher powers of transverse momentum is developed and applied to the Drell-Yan process, refining the understanding of its factorization structure. Finally, a new semi-analytical ansatz for the evolution of parton distributions is explored. Together, these methods improve analytic control over radiative corrections, kinematic dependence, and scale evolution in processes relevant to the Electron-Ion Collider and other collider experiments.
hep-phhep-th
27
Classification of order-two T-duality orbifolds at the SO(12) free fermionic point
Alon E. Faraggi🇬🇧 · Stefan Groot Nibbelink · Benjamin Percival🇬🇧
Asymmetric orbifolds provide concrete examples of non-geometric constructions dubbed T-folds. All Z2 point groups of six dimensional asymmetric order-two orbifolds are identified. The order-two T-fold configurations on the SO(12) lattice are classified at the fermionic point of type II string theories for all Z2 point groups. The spectra of the models on these configurations are presented parametrically, in terms of certain generalised GSO phases. The minimal effective Hodge numbers were found to be (h_{11},h_{12})=(1,1) for six T-fold configurations. Asymmetric generalisations of the mirror symmetry map are conjectured. The orientifoldable configurations using the basic worldsheet parity were identified within the classification. Twisted sectors corresponding to pure asymmetric twists may contain Rarita-Schwinger multiplets with spin-3/2 states. Throughout the paper, generalised GSO projections are chosen to preserve the maximal amount of supersymmetry possible. Relaxing this, the order-two point groups were identified for which non--supersymmetric T-folds can be constructed. Since some of them may enhance to N=1 or, even, N=2 supergravities, we argue that appearance of spin-3/2 states necessarily implies that the spectrum has reorder itself in a supersymmetric fashion and hence that the vacuum energy vanishes.
↳ hep-thhep-phmath-phmath.MP0 citations
28
Macroscopic Classical and Quantum Models of Inverse Compton Scattering
Emerson Rogers
Inverse Compton sources --- in which a relativistic electron beam scatters a laser pulse to produce tunable, collimated, high-energy radiation --- have emerged as promising compact radiation sources, with applications in nuclear photonics, medical imaging, and nanoscale metrology. As laser intensities increase and electron energies grow, the interaction enters the radiation reaction regime, where the energy radiated by the electron becomes a significant fraction of its kinetic energy. Predicting the scattered electron energy spectrum from first principles has remained an unsolved problem. Existing models are either classical equations of motion requiring large-scale multiparticle simulation, or quantum models relying on approximations of uncertain validity with the same simulation burden. None directly produce a spectral prediction. This dissertation presents a novel framework that resolves this deficiency. The laser pulse is represented as a coherent quantum state of the electromagnetic field and the electron beam as a statistical quantum state encoding its momentum distribution --- the natural realization of particle-field scattering within quantum electrodynamics. For a Gaussian laser pulse, a closed-form analytic expression for the scattered spectrum is derived requiring no simulation, no approximation of the laser field profile, and no large particle ensembles. The classical limit recovers Landau-Lifshitz dynamics exactly, establishing the coherent-state model as the quantum electrodynamic realization of classical radiation reaction theory. The framework is validated against existing experimental data, and fundamental structural limitations of all current modeling approaches are identified and analyzed.
↳ physics.acc-phhep-phphysics.plasm-ph
29
Analytical Solution of the Nonlinear Boltzmann Equation For Multicomponent Systems
Linyuan Wei · Yi Wang · Jin Hu · Baoyi Chen
We present exact analytical solutions to the nonlinear relativistic Boltzmann equation for homogeneous, isotropic massless multi-component systems with non-isotropic scattering cross sections. For a two-component system, we identify three distinct classes of exact solutions, each corresponding to specific constraints among initial energy densities, particle number densities, and scattering cross sections. These solutions comprise the equilibrium state and two novel classes: a hybrid structure featuring a non-equilibrium Maxwell-Juttner distribution coupled with a nontrivial distribution; the former is unprecedented in kinetic theory, while the latter refers to nontrivial dynamics shared by both species, which is novel in the relativistic context.
↳ cond-mat.stat-mechhep-phnucl-th
30
Dark Matter-Induced Stellar Oscillations in the de Broglie Regime
Qiuyue Liang · Jeremy Sakstein
We investigate stellar oscillations driven by the time-dependent gravitational potential of ultralight dark matter (ULDM) in the de Broglie regime. The response is controlled by the ratio of the ULDM coherence time to the stellar mode damping time. When the field decoheres faster than the damping time, ULDM acts as a stochastic source that excites modes below a characteristic de Broglie frequency, while higher-frequency modes are suppressed. In the opposite, long-coherence regime, individual modes can be resonantly driven. Focusing on solar oscillations, we find a signal far below current sensitivity, and estimate that other stars are similarly unlikely to provide observable signals.
↳ astro-ph.COgr-qchep-ph
31
Exploring the short-range correlations in $^{16}$ O+ $^{16}$ O collisions at the LHC
Qi Liu · Shanjin Wu · Huichao Song
Short-range correlations (SRCs) dominate the nuclear force at short distances, including the repulsive core and intermediate-range attraction, and are one of the most fascinating aspects of the nucleon-nucleon (NN) interaction. In this work, we investigate the effects of SRCs on the final-state observables in $^{16}$ O+ $^{16}$ O collisions at $s_{N N} = 5.36$ ~TeV, using the iEBE-VISHNU hybrid model with {T\raisebox{-0.5ex}{R}ENTo} initial conditions. We embed the nucleon configurations of $^{16}$ O generated from variational Monte Carlo (VMC) simulations with realistic SRCs in the initial stage, along with uncorrelated VMC samples and Woods--Saxon distributions implementing a hard repulsive core or short-range attraction as comparison runs. We find that SRCs reduce both $v_{2} {2}$ and $v_{2} {4}$ in the most central collisions, with the decrease of $v_{2} {4}$ being more pronounced due to the event-by-event flow fluctuations. Meanwhile, SRCs noticeably enhance the correlation between the elliptic flow and the mean transverse momentum, $ρ_{2} (v_{2}^{2}, [p_{T}])$ . These effects are mainly attributed to the strong repulsive core of the SRCs, which suppresses the probability of finding nucleon pairs at short relative distances and renders the initial geometry more uniform. This interpretation is supported by the calculations based on Woods--Saxon distributions with a hard repulsive core, which reproduce similar results, while the contribution from a pure intermediate-range attraction is negligible. Our results demonstrate that relativistic nuclear collisions provide a complementary probe of the short-range structure of the nuclear force, beyond the traditional nuclear experiments at low energies.
↳ nucl-thhep-ph
32
The refractive index of the medium within the volume of deep inelastic $e p$ scattering: I. Group velocity of interaction carriers
B. B. Levchenko
We propose a new method for measuring several characteristics of a fermion-boson medium formed during deep inelastic particle scattering. This method involves measuring the group and phase velocities of the accompanying wave process. The phase and group velocities of a wave process are related by the Rayleigh differential condition. The refractive index of a medium is determined by the phase velocity, while the group velocity characterises the medium's dispersion properties. In the case of deep inelastic $e p$ scattering under consideration, the wave process in an individual event is understood to be the exchange between an electron and a proton of an effective, non-perturbative mediator of interaction ( $B$ ) with the quantum numbers of a neutral current. In the first report, we present new data on the group velocity of interaction carriers $B$ . We extracted the group velocity modulus values, $U_{_{B}}^{*}$ , from the HERA collider data using a formula derived from modified Heisenberg uncertainty relations and applying the indirect measurement method.. etc...(see preprint text)
↳ quant-phhep-ph
33
On the Modes at the Schwarzschild Black Hole Horizon
Dimitrios Giataganas · Alex Kehagias · Antonio Riotto
We discuss the origin of the modes appearing at the Schwarzschild black hole horizon and decaying at integer multiples of the surface gravity. We argue that no excitations generated at the horizon by the plunging of a particle into a black hole can leave it. Our argument is based on the fact that, when the particle approaches the horizon, its speed is necessarily boosted to ultra-relativistic values and its near-horizon gravitational field becomes a Dray-'t Hooft shockwave, which is an exact, nonanalytic, and nonperturbative solution of Einstein's equations. The corresponding metric perturbations are localized at the horizon and can never reach a distant observer.
↳ gr-qchep-phhep-th
34
Strangeness Production in Heavy-Ion Collisions: Color Ropes or Hydrodynamic Evolution?
Carl Rosenkvist · Hannah Elfner
We investigate strangeness production and transverse dynamics in heavy-ion collisions at $s_{NN} \approx 2.5 - 20 GeV$ using the transport approach SMASH (Simulating Many Accelerated Strongly-interacting Hadrons), its extension with rope hadronization, and the SMASH+vHLLE hybrid approach. Results from the Pythia-based heavy-ion model Angantyr, with and without rope hadronization, are included for comparison. We study midrapidity particle yields and average transverse masses as functions of the number of wounded nucleons, as well as their energy dependence. For the $K^{+} / π^{+}$ ratio, SMASH+vHLLE overpredicts strangeness production at low energies but describes the higher-energy behavior reasonably well. SMASH+Ropes reproduces the ratio up to $s_{NN} \sim 10 GeV$ but does not capture the turnover at higher energies. In contrast, the transverse-mass observables favor the hybrid approach, while the non-thermal models considered here do not generate sufficient collective transverse expansion. These results show that strangeness enhancement alone does not uniquely distinguish microscopic string interactions from a locally equilibrated medium. Simultaneously constraining strangeness production and transverse dynamics is therefore essential for disentangling thermal and non-thermal mechanisms in heavy-ion collisions.
↳ nucl-thhep-ph
35
Mean- $p_{T}$ fluctuations in Au+Au collisions at $s_{NN} = 3.0$ -- $19.6$ GeV within JAM2
Yaqi Liu · Liuyao Zhang · Chunjian Zhang · Jinhui Chen · Chunwang Ma
Event-by-event mean- $p_{T}$ fluctuations probe initial-state fluctuations and their evolution through the dynamics of heavy-ion collisions. We study second-order mean- $p_{T}$ fluctuations in Au+Au collisions at $s_{NN} = 3.0$ -- $19.6$ GeV using JAM2 in the RQMDv mean-field mode with the MH2 parameterization. The model qualitatively reproduces the measured identified-particle $p_{T}$ spectra, providing a single-particle baseline for the fluctuation analysis. The scaled fluctuation $k_{2}$ decreases with increasing $⟨ N_{part} ⟩$ and shows broad agreement with the available measurements at 7.7--19.6 GeV, whereas its calculated centrality dependence is stronger than that in the data at 3.0--4.5 GeV. For the combined proton-plus-antiproton sample, the unnormalized correlator $⟨ c_{2} ⟩$ is positive and larger than that for charged pions. The charged-pion correlator $⟨ c_{2} ⟩$ is negative or consistent with zero over most centrality intervals at 3.0 and 3.5 GeV, becomes weakly positive at 4.5 GeV, and remains positive at higher energies. Its energy evolution resembles the change in the reaction-plane elliptic flow, but this comparison does not establish a common microscopic origin. These calculations provide species-dependent predictions within a transport model without an explicit partonic stage. Isolating the contributions of mean fields, rescattering, and spectator interactions requires controlled variations of the transport dynamics.
↳ nucl-exhep-ph

Affiliations

first authorsco-authorsvia INSPIRE