Tue·Nov 5, 2024Tuesday·November 5, 2024

1. 01*

   CP violation in loop-induced diboson production

   Marion O. A. Thomas🇬🇧 · Eleni Vryonidou🇬🇧

   We consider the impact of CP-violating Higgs and top interactions on diboson production from gluon fusion within the Standard Model Effective Field Theory framework. We systematically study differential distributions for double Higgs, double $W$ and $Z$ production and compare their features to those obtained from CP-conserving interactions. For electroweak gauge boson production, we explore the impact of the new interactions on the angular distributions of the leptonic decay products and the associated gauge boson polarisation fractions both inclusively and differentially with the transverse momentum of the gauge boson.

   hep-phJHEP(2025)·13 citations
2. 02*

   Compact objects and dark matter dynamics in astroparticle physics

   Ashadul Halder🇮🇳

   The quark star is such an exotic star of our Universe. The limiting mass for quark stars essentially depends on rotational frequency apart from bag constant and other fundamental parameters. The analytical results obtained agree with the results of several relevant numerical estimates as well as observational evidence. Primordial black hole (PBH) is another hypothetical candidate of compact astrophysical objects. We explore the combined effect of PBH evaporation and the baryon-dark matter (DM) interaction in the 21cm scenario. We address both upper and lower bounds on several PBH and DM parameters using the observational excess (-500^{+200}_{-500} mK) of EDGES's experimental results. A similar investigation has been carried out in the framework of interacting dark energy (IDE) models. We consider three IDE models and eventually measure the allowed limits of IDE coupling parameters for individual cases. Keeping in view of the 21cm scenario, we also explore the multimessenger signals from possible rare decay of fundamental Heavy Dark Matters (HDM). HDM can undergo QCD cascade decay to produce leptons or $\gamma$ as end products. One of the multimessenger signals could be the source of ultra high energy neutrino ($\sim$PeV) signals at the IceCube detector whereas the other signal attributes to the cooling/heating of the baryons due to HDM decay and corresponding influences in the global 21cm signal. The consequence of late time decay of such HDMs may also have significant implications on the aspect of matter-antimatter asymmetry. The mass and lifetime of such Dark Matter particles have been obtained by performing a ${\chi }^2$ analysis with the PeV neutrino data of IceCube and finally, the amount of baryon asymmetry produced in the Universe is estimated if caused by Dark Matter decay.

   hep-phastro-ph.CO2 citations
3. 03*

   Quantum coherence between mass eigenstates of a neutrino cannot be destroyed by its mass-momentum entanglement

   James M. Cline🇨🇦

   In the latest of a series of papers (arXiv:2410.21850), it has been claimed that neutrinos cannot oscillate as a consequence of their mass mixing. I clarify that this arises from the unrealistic assumption that neutrinos will always be in nearly exact eigenstates of energy, and ignoring the spatial dependence of the neutrino wave function. Taking into account the latter, neutrinos will be observed to oscillate in precisely the expected manner.

   hep-ph2 citations
4. 04*

   Estimate of virtual photon polarization due to the intense magnetic field in Pb-Pb collisions at the LHC energies

   Kento Kimura🇯🇵 · Nicholas J. Benoit🇯🇵 · Ken-Ichi Ishikawa🇯🇵 · Chiho Nonaka🇯🇵 · Kenta Shigaki🇯🇵

   We present the first numerical calculation of the virtual photon polarization and assess the feasibility of measuring the polarization via the anisotropic decay ${\gamma }^{\ast }\to \mu \mu$ using the LHC-ALICE detector. In presence of intense magnetic fields generated in high-energy non-central heavy-ion collisions that exceed the critical magnetic field intensity of quantum electrodynamics (QED), prompt virtual photons are predicted to decay anisotropically into lepton pairs, which we call virtual photon polarization. Using a relativistic resistive magnetohydrodynamics model, we computed the time evolution of the magnetic field and used these results to estimate the averaged polarization by calculating the vacuum polarization under the influence of the magnetic field at specific times. The estimated polarization deviates from zero with a statistical significance of $0.07\sigma$ with the data statistics collected from 2010 to 2011 and $0.15\sigma$ with the one from 2015 to 2018. It is understandable that the magnetic field could not be detected through polarization due to low statistical significance. With the data collecting the ongoing ALICE run from 2023 to 2026, the statistics dramatically increase by the upgraded LHC and the new data processing system. Thereby we expect that the statistical significance could reach $\sim 1.7\sigma$, resulting in a promising probe for detecting the intense magnetic fields.

   hep-phPLB(2025)·3 citations
5. 05*

   Three-dimensional calculations of positron creation in supercritical collisions of heavy nuclei

   N.K. Dulaev🇷🇺 · D.A. Telnov🇷🇺 · V.M. Shabaev🇷🇺 · Y.S. Kozhedub🇷🇺 · X. Ma🇨🇳 · I. A. Maltsev🇷🇺 · R. V. Popov🇷🇺 · I. I. Tupitsyn🇷🇺

   Energy--angle differential and total probabilities of positron creation in slow supercritical collisions of two identical heavy nuclei are calculated beyond the monopole approximation. The time-dependent Dirac equation (TDDE) for positrons is solved using the generalized pseudospectral method in modified prolate spheroidal coordinates, which are well-suited for description of close collisions in two-center quantum systems. In the frame of reference where the quasimolecular axis is fixed, the rotational coupling term is added to the Hamiltonian. Unlike our previous calculations, we do not discard this term and retain it when solving the TDDE. Both three-dimensional angle-resolved and angle-integrated energy distributions of outgoing positrons are obtained. Three-dimensional angle-resolved distributions exhibit a high degree of isotropy. For the collision energies in the interval 6 to 8 MeV/u, the influence of the rotational coupling on the distributions and total positron creation probabilities is quite small.

   hep-phPRD(2025)·4 citations
6. 06*

   Short- vs Long-Distance Dynamics in $b\to s\bar{\ell }\ell$ Decays

   Arianna Tinari🇨🇭

   The tension of $B\to K^{(\ast )}\bar{\ell }\ell$ decays with the Standard Model (SM) can be attributed to a short-distance (SD) $bs\bar{\ell }\ell$ interaction. We show two methods to disentangle this effect from long-distance (LD) dynamics. Firstly, we perform a comparison of the inclusive $b\to s\bar{\ell }\ell$ rate at high $q^2=m_{\ell \ell }^2\ge 15\mathrm{Ge}{\mathrm{V}}^2$ with a determination based on data on the leading exclusive modes, finding a $\sim 2\sigma$ discrepancy. Secondly, we analyze the exclusive $B\to K^{(\ast )}\bar{\ell }\ell$ spectrum in the entire $q^2$ region. With a dispersive parametrization of the charmonia resonances, we extract the non-SM contribution to the Wilson coefficient $C_9$ for every bin in $q^2$. The result is compatible with the SD hypothesis and the inclusive determination. Finally, with the aim of having better control over LD effects that mimic the $C_9$ contribution, we estimate the size of a few charm-rescattering processes in $B\to K\bar{\ell }\ell$.

   hep-phPoS(2025)·0 citations
7. 07*

   Channeling, Radiation and Reactions in Crystals at High Energy

   Vladimir Baryshevsky🇧🇾

   Author-made translation of the book published in Russian in 1982. Chapter 1. Channeling of High-Energy Particles in Crystals. Chapter 2. A Channeled Fast Particle as a 2D (1D) Relativistic Atom. Chapter 3. The Foundations of the Theory of $\gamma$-quanta Emission in Crystals under Channeling Conditions. Chapter 4. The Influence of $\gamma$-quanta Refraction and Diffraction on Angular and Spectral Characteristics of Radiation Produced by Particles in Crystals. Chapter 5. Classical Theory of Radiation Formation by Particles in a Medium. Chapter 6. Scattering and Radiation in Crystals Exposed to Variable Fields. Chapter 7. Interference of Independently Generated Beams of $\gamma$-quanta. Chapter 8. Theory of Measurement of Nuclear Reaction Times Using Shadow Effect. Yield of Reactions Induced by High-energy Particles in Crystals. Chapter 9. Spin Rotation and Radiative Self-Polarization of Particles Moving in Bent Crystals. Chapter 10. The Influence of Radiative Transitions on Channeling of Charged Particles in Crystals.

   hep-ph0 citations
8. 08*

   Neutrinos in the flavor-dependent $U(1{)}_F$ model

   Jin-Lei Yang🇨🇳 · Jie Li🇨🇳

   The neutrino oscillation experiments provide definitive evidence of new physics beyond the Standard Model (SM), and the neutrino mass-squared differences and flavor mixing have been precisely measured. This study examines the neutrino sector within the flavor-dependent $U(1{)}_F$ model, where the unique fermion sector can simultaneously address both the flavor mixing puzzle and the mass hierarchy puzzle. It is found that the lightest neutrino is naturally massless in this model, and the predicted neutrino mass-squared differences, flavor mixing angles, Dirac CP phase agree well with the experimental measurements. Additionally, the effects of the Dirac CP phase and Majorana CP phase on the theoretical predictions of the neutrino transition magnetic dipole moments are analyzed.

   hep-phPRD(2024)·3 citations
9. 09*

   Mixing angle of $K_1(1270/1400)$ and the $K{\bar{K}}_1(1400)$ molecular interpretation of ${\eta }_1(1855)$

   Zheng-Shu Liu🇨🇳 · Xu-Liang Chen🇨🇳 · Ding-Kun Lian🇨🇳 · Ning Li🇨🇳 · Wei Chen🇨🇳

   Due to the SU(3) symmetry breaking effect, the axial-vector kaons $K_1(1270)$ and $K_1(1400)$ are established to be mixtures of two P-wave $K_{1A}\left({}^3{P}_1\right)$ and $K_{1B}\left({}^1{P}_1\right)$ states. In QCD sum rules, we propose a new construction of the $K_1$ current operators and calculate the two-point correlation functions by including the next-to-leading order four-quark condensates. The mixing angle is determined as $\theta ={\left(46.95_{-0.23}^{+0.25}\right)}^{\circ }$ by reproducing the masses of $K_1(1270)$ and $K_1(1400)$. We further compose the $K{\bar{K}}_1\left(1270\right)$ and $K{\bar{K}}_1\left(1400\right)$ interpolating currents with exotic quantum numbers $J^{PC}=1^{-+}$ to investigate the possible molecular interpretation of the recently observed ${\eta }_1(1855)$ state. We calculate the correlation functions and perform the QCD sum rule analyses for these two molecular systems. However, the spectral functions are found to be negative in physical regions so that they are not able to provide reliable investigations of the $K{\bar{K}}_1$ molecular states.

   hep-phhep-exPRD(2025)·8 citations
10. 10*

    Production and decay of anticharmed pentaquark state with quark content $\bar{c}sudd$

    Shi-Dong Liu🇨🇳 · Xiao-Yun Wang🇨🇳 · Xiao-Hai Liu🇨🇳 · Gang Li🇨🇳

    We used an effective Lagrangian approach to investigate the production of the anticharmed pentaquark state $P_{\bar{c}s}^{(\ast )-}$ with the minimal quark content $\bar{c}sudd$ in the ${\Lambda }_b^0$ decay and its decay into the $\Lambda D^{(\ast )-}$ and $\Sigma D^{(\ast )-}$. In our calculation, the $P_{\bar{c}s}^{(\ast )-}$ is considered as the molecule state of the $n{D}_{s0(s1)}^{-}$ in an $S$ wave, and its production and decay occur via triangle loops at the hadron level. The predicted branching fractions for the processes ${\Lambda }_b^0\to P_{\bar{c}s}^{(\ast )-}{D}^{+}$ are around $10^{-4}\sim 10^{-3}$. The partial decay widths of the $P_{\bar{c}s}^{(\ast )-}\to \Lambda D^{(\ast )-}$ are between $0.1$ and $\sim 10\mathrm{MeV}$, whereas the decay widths of the $P_{\bar{c}s}^{(\ast )-}\to \Sigma D^{(\ast )-}$ are about one order of magnitude smaller. It is found that the width ratios for the $P_{\bar{c}s}^{(\ast )-}$ decays are nearly independent of the model parameter $\alpha$. It is hoped that these predictions could be helpful in searching for the anticharmed-strange pentaquark candidates in future LHCb experiments.

    hep-phEPJC(2025)·0 citations
11. 11*

    Enhancing Bayesian parameter estimation by adapting to multiple energy scales in RHIC and LHC heavy-ion collisions

    Maxim Virta🇫🇮 · Jasper Parkkila🇵🇱 · Dong Jo Kim🇫🇮

    Improved constraints on current model parameters in a heavy-ion collision model are established using the latest measurements from three distinct collision systems. Various observables are utilized from Au--Au collisions at $\sqrt{s_{\mathrm{NN}}}=200$~GeV and Pb--Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$~TeV and $\sqrt{s_{\mathrm{NN}}}=2.76$~TeV. Additionally, the calibration of centrality is now carried out separately for all parametrizations. The inclusion of an Au--Au collision system with an order of magnitude lower beam energy, along with separate centrality calibration, suggests a preference for smaller values of nucleon width, minimum volume per nucleon, and free-streaming time. The results with the acquired \textit{maximum a posteriori} parameters show improved agreement with the data for the second-order flow coefficient, identified particle yields, and mean transverse momenta. This work contributes to a more comprehensive understanding of heavy-ion collision dynamics and sets the stage for future improvements in theoretical modeling and experimental measurements.

    hep-phnucl-exnucl-thPRC(2025)·11 citations
12. 12*

    Line shape of the $J\psi \to \gamma {\eta }_c$ decay

    Ting Wang🇨🇳 · Xiaolong Wang🇨🇳 · Guangrui Liao🇨🇳 · Kai Zhu🇨🇳

    An accurate description of the photon spectrum line shape is essential for extracting resonance parameters of the ${\eta }_c$ meson through the radiative transition $J/\psi \to \gamma {\eta }_c$. However, a persistent challenge remains in the form of a divergent tail at high photon energies, arising from the $E_{\gamma }^3$ factor in theoretical calculations. Various damping functions have been proposed to mitigate this effect in practical experiments, but their empirical nature lacks a rigorous theoretical basis. In this study, we introduce two key considerations: incorporating full-order contributions of the Bessel function in the overlap integral of charmonium wave functions and the phase space factor neglected in previous experimental studies. By accounting for these factors, we demonstrate a more rational and effective damping function of the divergent tail associated with the $E_{\gamma }^3$ term. We present the implications of these findings on experimental measurements and provide further insights through toy Monte Carlo simulations.

    hep-phhep-exPRD(2025)·0 citations
13. 13*

    Derivation of the Balitsky-Kovchegov Equation for Quark-Quark Scattering

    Cong Li🇨🇳

    We derived the BK equation for quark-quark scattering, extending the dipole-hadron scattering framework. This derivation reveals that the quark-quark scattering amplitude grows with increasing quark rapidity. Since the momentum dot product is Lorentz invariant, the coupling constant plays a crucial role in accounting for it.

    hep-ph0 citations
14. 14*

    A minimalistic model for inelastic dark matter

    Giovani Dalla Valle Garcia🇩🇪

    Models of inelastic (or pseudo-Dirac) dark matter commonly introduce a gauge symmetry spontaneously broken by the introduction of a dark sector version of the Higgs mechanism. We find that this ubiquitous introduction of two extra fields, a vector and a complex scalar boson, is indeed unnecessary, with only a mass generating real scalar field being actually required. We consider a simple UV-complete model realizing this minimal setup and study the decays of the excited dark matter state as well as constraints from perturbative unitarity, (in)direct detection and colliders. We find that, in the visible freeze-out scenario ($\text{DM}\text{DM}\leftrightarrow \text{SM}\text{SM}$), we still have unconstrained regions of parameter space for dark matter masses $\gtrsim 100$~GeV. Moreover, most of the available regions either present long-lived excited states, which are expected to interfere with the standard cosmological history, or will be probed by future direct detection experiments, such as DARWIN, due to the unavoidable residual elastic interactions. The only regions remaining out of experimental reach present highly fine-tuned parameters.

    hep-phPLB(2025)·14 citations
15. 15*

    Physics-informed neural networks viewpoint for solving the Dyson-Schwinger equations of quantum electrodynamics

    Rodrigo Carmo Terin🇪🇸

    Physics-informed neural networks (PINNs) are employed to solve the Dyson--Schwinger equations of quantum electrodynamics (QED) in Euclidean space, with a focus on the non-perturbative generation of the fermion's dynamical mass function in the Landau gauge. By inserting the integral equation directly into the loss function, our PINN framework enables a single neural network to learn a continuous and differentiable representation of the mass function over a spectrum of momenta. Also, we benchmark our approach against a traditional numerical algorithm showing the main differences among them. Our novel strategy, which is expected to be extended to other quantum field theories, is the first step towards forefront applications of machine learning in high-level theoretical physics.

    hep-phcs.LGhep-thSciPost Phys.Core(2025)·7 citations
16. 16*

    Rejection Sampling with Autodifferentiation - Case study: Fitting a Hadronization Model

    Nick Heller🇺🇸 · Phil Ilten🇺🇸 · Tony Menzo🇺🇸 · Stephen Mrenna🇺🇸 · Benjamin Nachman🇺🇸 · Andrzej Siodmok🇵🇱 · Manuel Szewc🇺🇸 · Ahmed Youssef🇺🇸

    We present an autodifferentiable rejection sampling algorithm termed Rejection Sampling with Autodifferentiation (RSA). In conjunction with reweighting, we show that RSA can be used for efficient parameter estimation and model exploration. Additionally, this approach facilitates the use of unbinned machine-learning-based observables, allowing for more precise, data-driven fits. To showcase these capabilities, we apply an RSA-based parameter fit to a simplified hadronization model.

    hep-phhep-ex5 citations
17. 17*

    NLO QCD predictions for $\mathbf{t}\bar{\mathbf{t}}\mathbf{\gamma }$ with realistic photon isolation

    Daniel Stremmer🇩🇪 · Malgorzata Worek🇩🇪

    We present a complete description of top quark pair production in association with a hard photon in the di-lepton decay channel. The calculation is performed at NLO QCD and includes all resonant and non-resonant Feynman diagrams, interferences, and finite-width effects of the top quarks and $W^{\pm }/Z$ gauge bosons. We provide the results for the $pp\to e^{+}{\nu }_e{\mu }^{-}\bar{\nu }b\bar{b}\gamma +X$ process using the fixed-cone, smooth-cone and hybrid-photon isolation criteria. The fixed-cone isolation criterion allows contributions from collinear photon radiation off QCD partons, which requires the inclusion of parton-to-photon fragmention processes. To this end, we include the latter contributions into our computational framework. We quantify the impact of different photon-isolation prescriptions on the integrated and differential cross-section predictions for the LHC at a centre-of-mass energy of $\sqrt{s}=13.6$ TeV. Our state-of-the-art NLO QCD results with the fixed-cone criterion allow us to reproduce the photon-isolation prescription employed in ATLAS and CMS. This will help to improve future comparisons with the LHC data.

    hep-phhep-exJHEP(2025)·6 citations
18. 18*

    Radially excited pion: electromagnetic form factor and the box contribution to the muon's $g-2$

    Angel S. Miramontes🇪🇸 · K. Raya🇪🇸 · A. Bashir🇲🇽 · P. Roig🇲🇽 · G. Paredes-Torres🇲🇽

    We investigate the properties of the radially excited charged pion, with a specific focus on its electromagnetic form factor (EFF) and its box contribution to the hadronic light-by-light (HLbL) component of the muon's anomalous magnetic moment, $a_{\mu }$. Utilizing a coupled non-perturbative framework combining Schwinger-Dyson and Bethe-Salpeter equations, we first compute the mass and weak decay constant of the pion's first radial excitation. Initial results are provided for the Rainbow-Ladder (RL) approximation, followed by an extended beyond RL (BRL) analysis that incorporates meson cloud effects. Building on our previous work, this analysis demonstrates that an accurate description of the first radial excitation can be achieved without the need for a reparametrization of the interaction kernels. Having demonstrated the effectiveness of the truncation scheme, we proceed to calculate the corresponding EFF, from which we derive the contribution of the pion's first radial excitation to the HLbL component of the muon's anomalous magnetic moment, producing $a_{\mu }^{{\pi }_1-\text{box}}(\text{RL})=-(2.03\pm 0.12)\times 10^{-13}$, $a_{\mu }^{{\pi }_1-\text{box}}(\text{BRL})=-(2.02\pm 0.10)\times 10^{-13}$. Our computation also sets the groundwork for calculating related pole contributions of excited pseudoscalar mesons to $a_{\mu }$.

    hep-phnucl-thCPC(2025)·14 citations
19. 19*

    OPITeR: A program for tensor reduction of multi-loop Feynman Integrals

    Jae Goode🇬🇧 · Franz Herzog🇬🇧 · Sam Teale🇬🇧

    We present OPITeR, a FORM program for the reduction of multi-loop tensor Feynman integrals. The program can handle tensors, including spinor indices, with rank of up to 20 and can deal with up to 8 independent external momenta. The reduction occurs in $D$ dimensions compatible with conventional dimensional regularization. The program is able to manifest symmetries of the integrand in the tensor reduced form.

    hep-phhep-thComput.Phys.Commun.(2025)·19 citations
20. 20*

    New Tool to Detect Inhomogeneous Chiral Symmetry Breaking

    Theo F. Motta🇩🇪 · Julian Bernhardt🇩🇪 · Michael Buballa🇩🇪 · Christian S. Fischer🇩🇪

    In this letter, we discuss a novel method to search for inhomogeneous chiral symmetry breaking in theories with fermions. The prime application we have in mind is QCD, but the method is also applicable for other theories, including solid-state applications. It is based on an extension of the chiral susceptibility to inhomogeneous phases and it works as a stability analysis. Our method allows us to determine when homogeneous solutions have the tendency to create spatially modulated condensates. As proof of principle, we apply this technique to a rainbow-ladder QCD model and find that its phase diagram contains an inhomogeneous region.

    hep-phnucl-thPRD(2025)·18 citations
21. 21*

    Searching for signals of an exotic $I=1,J^P=2^{+}$ state of $D^{\ast }{K}^{\ast }$ nature and the structure of the $P_c(4312)$ in the ${\Lambda }_b\to {\Sigma }_c^{++}{D}^{-}{K}^{-}$ reaction

    Jing Song🇨🇳 · Zi-Ying Yang🇨🇳 · Eulogio Oset🇪🇸

    This paper investigates the decay process ${\Lambda }_b\to {\Sigma }_c^{++}{D}^{-}{K}^{-}$ with the objective of finding a predicted molecular state with isospin $I=1$, $J^P=2^{+}$ of $D^{\ast }{K}^{\ast }$ nature, plus finding support for the $P_c(4312)$ state as made out of ${\Sigma }_c\bar{D}$. The mass distribution of the $D^{-}{K}^{-}$ system shows distinct features as a consequence of the existing of this $2^{+}$ state, while the ${\Sigma }_c\bar{D}$ distribution exhibits a significant peak near the threshold, much bigger than phase space expectations, which is linked to our assumed ${\Sigma }_c\bar{D}$ nature of the $P_c(4312)$ state below the ${\Sigma }_c\bar{D}$ threshold. The reaction has been measured at LHCb Collaboration, but only the branching ratio is measured. The present study shows that much valuable information can be obtained about the predicted $2^{+}$ $T_{c\bar{s}}(2834)$ of $D^{\ast }{K}^{\ast }$ nature and the $P_c(4312)$ states from the measurements of the mass distributions in this reaction, which will be accessible in the planned updates of LHCb.

    hep-phPLB(2025)·4 citations
22. 22*

    LHC EFT WG Note: Basis for Anomalous Quartic Gauge Couplings

    Gauthier Durieux🇧🇪 · Grant N. Remmen🇺🇸 · Nicholas L. Rodd🇺🇸 · O. J. P. Éboli🇧🇷 · M. C. Gonzalez-Garcia🇺🇸 · Dan Kondo🇯🇵 · Hitoshi Murayama🇺🇸 · Risshin Okabe🇯🇵

    In this note, we give a definitive basis for the dimension-eight operators leading to quartic -- but no cubic -- interactions among electroweak gauge bosons. These are often called anomalous quartic gauge couplings, or aQGCs. We distinguish in particular the CP-even ones from their CP-odd counterparts.

    hep-phhep-exhep-thSciPost Phys.Comm.Rep.(2025)·15 citations
23. 23*

    New Physics Through Flavor Tagging at FCC-ee

    Admir Greljo🇨🇭 · Hector Tiblom🇨🇭 · Alessandro Valenti🇨🇭

    Leveraging recent advancements in machine learning-based flavor tagging, we develop an optimal analysis for measuring the hadronic cross-section ratios $R_b$, $R_c$, and $R_s$ at the FCC-ee during its $WW$, $Zh$, and $t\bar{t}$ runs. Our results indicate up to a two-order-of-magnitude improvement in precision, providing an unprecedented test of the SM. Using these observables, along with $R_{\ell }$ and $R_t$, we project sensitivity to flavor non-universal four-fermion (4F) interactions within the SMEFT, contributing both at the tree level and through the renormalization group (RG). We highlight a subtle complementarity with RG-induced effects at the FCC-ee's $Z$-pole. Our analysis demonstrates significant improvements over the current LEP-II and LHC bounds in probing flavor-conserving 4F operators involving heavy quark flavors and all lepton flavors. As an application, we explore simplified models addressing current $B$-meson anomalies, demonstrating that FCC-ee can effectively probe the relevant parameter space. Finally, we design optimized search strategies for quark flavor-violating 4F interactions.

    hep-phhep-exSciPost Phys.(2025)·36 citations
24. 24*

    Axion Astrophysics

    Pierluca Carenza🇸🇪 · Maurizio Giannotti🇪🇸 · Jordi Isern🇪🇸 · Alessandro Mirizzi🇮🇹 · Oscar Straniero🇮🇹

    Stars have been recognized as optimal laboratories to probe axion properties. In the last decades there have been significant advances in this field due to a better modelling of stellar systems and accurate observational data. In this work we review the current status of constraints on axions from stellar physics. We focus in particular on the Sun, globular cluster stars, white dwarfs and (proto)-neutron stars.

    hep-phastro-ph.SRhep-exhep-thPhys.Rept.(2025)·89 citations
25. 25*

    Generative Unfolding with Distribution Mapping

    Anja Butter🇩🇪 · Sascha Diefenbacher🇺🇸 · Nathan Huetsch🇩🇪 · Vinicius Mikuni🇺🇸 · Benjamin Nachman🇺🇸 · Sofia Palacios Schweitzer🇩🇪 · Tilman Plehn🇩🇪

    Machine learning enables unbinned, highly-differential cross section measurements. A recent idea uses generative models to morph a starting simulation into the unfolded data. We show how to extend two morphing techniques, Schrödinger Bridges and Direct Diffusion, in order to ensure that the models learn the correct conditional probabilities. This brings distribution mapping to a similar level of accuracy as the state-of-the-art conditional generative unfolding methods. Numerical results are presented with a standard benchmark dataset of single jet substructure as well as for a new dataset describing a 22-dimensional phase space of Z + 2-jets.

    hep-phcs.LGhep-exSciPost Phys.(2025)·19 citations
26. 26*

    Introduction to Thermal Field Theory: From First Principles to Applications

    Alberto Salvio🇮🇹

    This review article provides the basics and discusses some important applications of thermal field theory, namely the combination of statistical mechanics and relativistic quantum field theory. In a first part the fundamentals are covered: the density matrix, the corresponding averages and the treatment of fields of various spin in a medium. A second part is dedicated to the computation of thermal Green's function for scalars, vectors and fermions with path-integral methods. These functions play a crucial role in thermal field theory, as explained here. A more applicative part of the review is dedicated to the production of particles in a medium and to phase transitions in field theory, including the process of vacuum decay in a general theory featuring a first-order phase transition. To understand this review, the reader should only have a good knowledge of non-statistical quantum field theory.

    hep-phastro-ph.COhep-thUniverse(2025)·17 citations
27. 27*

    Limits on Kaluza-Klein Portal Dark Matter Models

    R. Sekhar Chivukula🇺🇸 · Joshua A. Gill🇦🇺 · Kirtimaan A. Mohan🇺🇸 · George Sanamyan🇦🇺 · Dipan Sengupta🇦🇺 · Elizabeth H. Simmons🇺🇸 · Xing Wang🇺🇸

    We revisit the phenomenology of dark-matter (DM) scenarios within radius-stabilized Randall-Sundrum models. Specifically, we consider models where the dark matter candidates are Standard Model (SM) singlets confined to the TeV brane and interact with the SM via spin-2 and spin-0 gravitational Kaluza-Klein (KK) modes. We compute the thermal relic density of DM particles in these models by applying recent work showing that scattering amplitudes of massive spin-2 KK states involve an intricate cancellation between various diagrams. Considering the resulting DM abundance, collider searches, and the absence of a signal in direct DM detection experiments, we show that spin-2 KK portal DM models are highly constrained. We confirm that within the usual thermal freeze-out scenario, scalar dark matter models are essentially ruled out. In contrast, we show that fermion and vector dark matter models are viable in a region of parameter space in which dark matter annihilation through a KK graviton is resonant. Specifically, vector models are viable for dark matter masses ranging from 1.1 TeV to 5.5 TeV for theories in which the scale of couplings of the KK modes is of order 40 TeV or lower. Fermion dark matter models are viable for a similar mass region, but only for KK coupling scales of order 20 TeV. In this work, we provide a complete description of the calculations needed to arrive at these results and, in an appendix, a discussion of new KK-graviton couplings needed for the computations, which have not previously been discussed in the literature. Here, we focus on models in which the radion is light, and the back-reaction of the radion stabilization dynamics on the gravitational background can be neglected. The phenomenology of a model with a heavy radion and the consideration of the effects of the radion stabilization dynamics on the DM abundance are being addressed in forthcoming work.

    hep-phastro-ph.COhep-exhep-thPRD(2025)·12 citations
28. 28*

    Dark hyperCharge Symmetry

    Hemant Prajapati🇮🇳 · Rahul Srivastava🇮🇳

    We introduce a new class of $U(1{)}_X$ symmetries where all Standard Model fermions are ``chiral," i.e., the left- and right-handed components have different charges under the $U(1{)}_X$ symmetry. Gauge anomaly cancellation is achieved by introducing three Standard Model gauge singlet dark fermions ($f^i$; $i=1,2,3$) charged under this symmetry. We systematically present chiral solutions for cases in which (a) one, (b) two, or (c) all three generations of Standard Model fermions are charged under the $U(1{)}_X$ symmetry. The $U(1{)}_X$ charges of these dark fermions are uniquely determined by anomaly cancellation conditions. These new fermions belong to the dark sector, with the lightest of them being a good dark matter candidate. Additionally, the $Z^{\prime }$ gauge boson mediates interactions between the dark and visible sectors, and we call this $U(1{)}_X$ symmetry as the ``dark hyperCharge" symmetry. Using a benchmark model, we explore phenomenological implications in the heavy $Z^{\prime }$ case ($M_{Z^{\prime }}>M_Z$), analyzing collider constraints and examining the lightest dark fermion's viability as dark matter. Our analysis shows that it satisfies all current dark matter constraints over a wide range of dark matter mass.

    hep-phPRD(2026)·9 citations
29. 29*

    Adiabatic state preparation for digital quantum simulations of QED in 1 + 1D

    Matteo D'Anna🇨🇭 · Marina Krstic Marinkovic🇨🇭 · Joao C. Pinto Barros🇨🇭

    Quantum electrodynamics in 1 + 1D (QED2) shares intriguing properties with QCD, including confinement, string breaking, and interesting phase diagram when the non-trivial topological $\theta$-term is considered. Its lattice regularization is a commonly used toy model for quantum simulations of gauge theories on near-term quantum devices. In this work, we address algorithms for adiabatic state preparation in digital quantum simulations of QED2. We demonstrate that, for specific choices of parameters, the existing adiabatic procedure leads to level crossing between states of different charge sectors, preventing the correct preparation of the ground state. We further propose a new adiabatic Hamiltonian and verify its efficiency in targeting systems with a nonzero topological $\theta$-term and in studying string breaking phenomena.

    ↳ hep-lathep-phnucl-thquant-phPRD(2025)·11 citations
30. 30*

    Quark jet evolution: from classical to quantum simulation

    Meijian Li🇪🇸

    Quark jet provides one of the best ways to probe the matter produced in ultrarelativistic high-energy collisions, from cold nuclear matter to the hot quark-gluon plasma. In this proceeding paper, we review a series of works on the development of nonperturbative computational framework of in-medium quark jet evolution, from classical to quantum simulation. The application of the time-dependent Basis Light-front Quantization (tBLFQ), a nonperturbative computational approach based on light-front Hamiltonian formalism, to in-medium jet evolution enables a fully quantum treatment to the jet state on the amplitude level. Based on the tBLFQ framework, with applying novel quantum technologies, we have constructed a digital quantum circuit that tracks the evolution of a multi-particle jet probe within a stochastic color background field. With the obtained simulation results, we extracted the medium induced modification in terms of jet momentum broadening and gluon production. These studies provide a baseline for future works of in-medium jet evolution using quantum computers.

    ↳ nucl-thhep-phquant-phPoS(2025)·3 citations
31. 31*

    More Nonlinearities? II. A Short Guide of First- and Second-Order Electromagnetic Perturbations in the Schwarzschild Background

    Fawzi Aly🇺🇸 · Mahmoud A. Mansour🇯🇵 · Dejan Stojkovic🇺🇸

    We study second-order electromagnetic perturbations in the Schwarzschild background and derive the effective source terms for Regge-Wheeler equation which are quadratic in first-order gravitational and electromagnetic perturbations. In addition to the induced mixed quadratic modes, we find that linear gravitational modes are also excited, with amplitudes dependent on the electromagnetic potential. A toy model involving a Dirac delta function potential demonstrates mixing of linear gravitational and electromagnetic perturbations with frequencies \( \omega^{(1)} \) and \( \Omega^{(1)} \), resulting in the second-order QNM mixing in the electromagnetic field at \( \Omega^{(2)} =\Omega^{(1)} + \omega^{(1)} \). This complements prior work in \cite{aly2024nonlinearities} on the second-order gravitational perturbation mixing and highlights potential applications in multi-messenger astrophysics for systems observed by LIGO-Virgo-KAGRA (LVK) and upcoming LISA. We also study first-order perturbations due to a point charge and show it could be reduced to a one-dimensional path integral. Within the toy model, we investigate the first-order electromagnetic perturbation due to a radially free-falling single charge \( q \) and radial dipole moment \( p = q \eta \), employing semi-analytical and numerical methods. For the dipole case, we show that the QNM perturbation is excited with a nearly constant amplitude. Future work will focus on incorporating mixing in more realistic potentials and exploring numerical approach in the context of rotating spacetimes.

    ↳ gr-qchep-phhep-thmath-ph+1PRD(2025)·3 citations
32. 32*

    A New Limit on the Graviton Mass from the Convergence Scale of the CMB Dipole

    Abraham Loeb (Harvard)🇺🇸

    The clustering dipole in the 2MASS galaxy survey converges on a scale of ~400Mpc to the local peculiar velocity inferred from the Cosmic-Microwave-Background dipole. I show that this limits the graviton mass in Yukawa theories of gravity to less than 5x10^{-32}eV. The new limit is 2.5x10^8 times tighter than the latest constraint from gravitational waves detected by the LIGO-Virgo-KAGRA collaboration.

    ↳ astro-ph.COgr-qchep-phRes.Notes AAS(2024)·3 citations
33. 33*

    Higgs Self-coupling Strategy at Linear e${}^{+}$e${}^{-}$ Colliders

    Bryan Bliewert🇩🇪 · Jenny List🇩🇪 · Dimitris Ntounis🇺🇸 · Junping Tian🇯🇵 · Julie Munch Torndal🇩🇪 · Caterina Vernieri🇺🇸

    The determination of the Higgs self-coupling is a key target for future colliders, in particular through di-Higgs production at $e^{+}{e}^{-}$ Linear Colliders with $\sqrt{s}>450$\,GeV, e.g.\ ILC, C3 or CLIC. This contribution will discuss the roles and the interplay of di-Higgs production processes at various collider energies, including the case of non-SM values of the self-coupling. Previous studies, already based on Geant4-based detector simulation, established that the Higgs self-coupling can be extracted with $10-27\%$ precision and provided a solid understanding of the limiting factors. This provides a robust starting point to explore the potential of more modern and sophisticated reconstruction and analysis techniques. We summarize the impact of advanced, often machine-learning-based algorithms, including e.g.\ jet clustering, kinematic fitting and matrix element-inferred likelihoods on the reconstruction of $ZHH$ events and before discussing the dependence of the projected precision on the center-of-mass energy and on the actual value of the self-coupling.

    ↳ hep-exhep-phPoS(2025)·4 citations
34. 34*

    Quantum Rationale-Aware Graph Contrastive Learning for Jet Discrimination

    Md Abrar Jahin🇺🇸 · Md. Akmol Masud🇬🇧 · M. F. Mridha🇧🇩 · Nilanjan Dey🇮🇳 · Zeyar Aung🇦🇪

    In high-energy physics, particle jet tagging plays a pivotal role in distinguishing quark from gluon jets using data from collider experiments. While graph-based deep learning methods have advanced this task beyond traditional feature-engineered approaches, the complex data structure and limited labeled samples present ongoing challenges. More broadly, our primary focus is the development of a rationale-aware graph contrastive learning framework designed to operate under strict resource constraints; we use quark-gluon jet discrimination as a representative and practically relevant use case. However, existing contrastive learning (CL) frameworks struggle to leverage rationale-aware augmentations effectively, often lacking supervision signals that guide the extraction of salient features and facing computational efficiency issues such as high parameter counts. In this study, we demonstrate that integrating a quantum rationale generator (QRG) within our proposed Quantum Rationale-aware Graph Contrastive Learning (QRGCL) framework enables competitive jet discrimination performance, particularly in parameter-constrained settings, reducing reliance on labeled data, and capturing rationale-aware features. Evaluated on the quark-gluon jet dataset, QRGCL achieves an AUC score of $77.5\%$ while maintaining a compact architecture of only 45 QRG parameters, achieving competitive performance compared to classical, quantum, and hybrid benchmarks. These results highlight QRGCL's potential to advance jet tagging and other complex classification tasks in high-energy physics, where computational efficiency and limitations in feature extraction persist.

    ↳ cs.LGhep-phTransactions on Machine Learning Research…·1 citation
35. 35*

    The role of intermediate $\Delta \Delta$ states in nucleon-nucleon scattering in the large-$N_c$ and unitary limits, and $\Delta \Delta$ and $\Omega \Omega$ scattering

    Thomas R. Richardson🇺🇸 · Matthias R. Schindler🇺🇸 · Roxanne P. Springer🇺🇸

    We explore potential explanations for why using large-$N_c$ ($N_c$ is the number of colors) scaling to determine the relative size of few-nucleon low-energy operators agrees with experiment even when dynamical $\Delta$'s are not explicitly included. Given that the large-$N_c$ analysis is predicated on the nucleons and $\Delta$'s being degenerate, this is a curious result. We show that for purely $S$-wave interactions the relationships dictated by large-$N_c$ scaling are unaffected whether the $\Delta$ is included or not. In the case of higher partial waves that do not mix with $S$-waves, the impact of the $\Delta$ is perturbative, which makes the agreement with naive ($\Delta$-less) large-$N_c$ ordering unsurprising. For higher partial waves that mix with $S$-waves, the nucleon and $\Delta$ would need to decouple to get agreement with naive large-$N_c$ ordering. We find all $NN$, $\Delta N$, and $\Delta \Delta$ low energy coefficients for leading-order baryon-baryon scattering in $\Delta$-full pionless effective field theory in terms of the two independent parameters dictated by the SU($2F$) spin-flavor symmetry that arises in the $N_c\to \infty$ limit. Because of recent lattice QCD results and experimental interest, we extend our analysis to the three-flavor case to study $\Omega \Omega$ scattering. We show that in the unitary limit (where scattering lengths become infinite) one of the two SU($2F$) parameters is driven to zero, resulting in enhanced symmetries, which agree with those found in spin-1/2 entanglement studies.

    ↳ nucl-thhep-phJ.Phys.G(2025)·5 citations
36. 36*

    Proton decay in de Sitter environment

    G.E. Volovik🇷🇺

    The decay of proton in the de Sitter environment is governed by the temperature $T=H/\pi$, where $H$ is the Hubble parameter. This temperature is twice larger than the Gibbons-Hawking temperature $T_{\mathrm{GH}}=H/2\pi$. This demonstrates the physical difference of two processes. The temperature $T=H/\pi$ determines the proton decay rate in the local process which takes well inside the cosmological horizon. While the Gibbons-Hawking temperature can be related to the processes which involve the Hawking photons or other particles radiated from the cosmological horizon. The same temperature $T=H/\pi$ determines the radiation of electron-positron pairs by positron or by other object in the de Sitter environment. Creation of matter and its thermalization in the de Sitter heat bath leads to the energy exchange between matter and quantum vacuum and finally to the decay of the de Sitter state towards the Minkowski vacuum. The lesson for the Unruh effect is also discussed. One may expect the similar separation of effects governed by two different temperatures: the effects related to the Rindler horizon with the Unruh temperature $T_{\mathrm{U}}=a/2\pi$ and the local radiation with $T=a/\pi =2T_{\mathrm{U}}$.

    ↳ gr-qchep-ph4 citations
37. 37*

    Strong parity-violation effects induced by large-amplitude motions: A quantum-dynamics study of substituted chiral methanols

    Ayaki Sunaga🇯🇵

    An enhanced mechanism is proposed for the large-amplitude-motion-induced parity-violating frequency by integrating the exact quantum dynamics method with the relativistic electronic structure theory. The torsional wavefunctions and PV frequency shifts are obtained by the exact quantum dynamics method. The potential energy curve and PV energy along the torsional coordinates are calculated using the extended atomic mean-field two-component Hamiltonian. The predicted PV frequency shift for the torsional transition of CFClBrOH is approximately 100 times larger than that of the conventional C-F stretching mode of CHFClBr. The maximum PV frequency shift (3.2 Hz) is obtained in the CHBrIOH molecule.

    ↳ physics.atom-phhep-phphysics.chem-phJ.Chem.Phys.(2025)·2 citations
38. 38*

    Diamagnetic microchip traps for levitated nanoparticle entanglement experiments

    Shafaq Gulzar Elahi🇺🇸 · Martine Schut🇳🇱 · Andrew Dana🇺🇸 · Alexey Grinin🇺🇸 · Sougato Bose🇬🇧 · Anupam Mazumdar🇳🇱 · Andrew Geraci🇺🇸

    The Quantum Gravity Mediated Entanglement (QGEM) protocol offers a novel method to probe the quantumness of gravitational interactions at non-relativistic scales. This protocol leverages the Stern-Gerlach effect to create $\mathcal{O}(\sim \mu m)$ spatial superpositions of two nanodiamonds (mass $\sim 10^{-15}$ kg) with NV spins, which are then allowed to interact and become entangled solely through the gravitational interaction. Since electromagnetic interactions such as Casimir-Polder and dipole-dipole interactions dominate at this scale, screening them to ensure the masses interact exclusively via gravity is crucial. In this paper, we propose using magnetic traps based on micro-fabricated wires, which provide strong gradients with relatively modest magnetic fields to trap nanoparticles for interferometric entanglement experiments. The design consists of a small trap to cool the center-of-mass motion of the nanodiamonds and a long trap with a weak direction suitable for creating macroscopic superpositions. In contrast to permanent-magnet-based long traps, the micro-fabricated wire-based approach allows fast switching of the magnetic trapping and state manipulation potentials and permits integrated superconducting shielding, which can screen both electrostatic and magnetic interactions between nanodiamonds in a gravitational entanglement experiment. The setup also provides a possible platform for other tests of quantum coherence in macroscopic systems and searches for novel short-range forces.

    ↳ quant-phhep-phPRA(2025)·21 citations
39. 39*

    Scalable Quantum Simulations of Scattering in Scalar Field Theory on 120 Qubits

    Nikita A. Zemlevskiy🇺🇸

    Simulations of collisions of fundamental particles on a quantum computer are expected to have an exponential advantage over classical methods and promise to enhance searches for new physics. Furthermore, scattering in scalar field theory has been shown to be BQP-complete, making it a representative problem for which quantum computation is efficient. As a step toward large-scale quantum simulations of collision processes, scattering of wavepackets in one-dimensional scalar field theory is simulated using 120 qubits of IBM's Heron superconducting quantum computer ibm_fez. Variational circuits compressing vacuum preparation, wavepacket initialization, and time evolution are determined using classical resources. By leveraging physical properties of states in the theory, such as symmetries and locality, the variational quantum algorithm constructs scalable circuits that can be used to simulate arbitrarily-large system sizes. A new strategy is introduced to mitigate errors in quantum simulations, which enables the extraction of meaningful results from circuits with up to 4924 two-qubit gates and two-qubit gate depths of 103. The effect of interactions is clearly seen, and is found to be in agreement with classical Matrix Product State simulations. The developments that will be necessary to simulate high-energy inelastic collisions on a quantum computer are discussed.

    ↳ quant-phhep-lathep-phnucl-thPRD(2025)·79 citations
40. 40*

    Scattering of Quantum Particles in de Sitter Spacetime I: The Formalism

    Tomasz R. Taylor🇺🇸 · Bin Zhu🇬🇧

    We develop a formalism for computing the scattering amplitudes in maximally symmetric de Sitter spacetime with compact spatial dimensions. We describe quantum states by using the representation theory of de Sitter symmetry group and link the Hilbert space to geodesic observers. The positive and negative ``energy'' wavefunctions are uniquely determined by the requirement that in observer's neighborhood, short wavelengths propagate as plane waves with positive and negative frequencies, respectively; they define a unique ``Euclidean'' (a.k.a.\ Bunch-Davies) de Sitter invariant vacuum, common to all inertial observers. By following the same steps as in Minkowski spacetime, we show that the scattering amplitudes are given by a generalized Dyson's formula. Compared to the flat case, they describe the scattering of wavepackets with the frequency spectrum determined by geometry. The frequency spread shrinks as the masses and/or momenta become larger than the curvature scale. Asymptotically, de Sitter amplitudes agree with the amplitudes evaluated in Minkowski spacetime.

    ↳ hep-thgr-qchep-phNPB(2025)·6 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.