Tue·Oct 29, 2024Tuesday·October 29, 2024

1. 01*

   $\pi$-$\pi$ scattering lengths: electric corrections in the linear sigma model

   M. Loewe🇿🇦 · R. Cadiz · R. Zamora🇨🇱

   In the frame of the linear sigma model and working in the weak field approximation, we discuss the role played by an external electric field on the behavior of $\pi$-$\pi$ scattering lengths. For this purpose, we have considered all relevant one-loop diagrams in the $s$, $t$, and $u$ channels where we have Schwinger propagators for charged pions. An important novelty of our analysis, compared with previous existing discussions in the literature, is the explicit calculation of box diagrams which were previously not considered in discussions regarding magnetic corrections to $\pi$-$\pi$ scattering lengths. Our analysis shows that electric field corrections have an opposite effect with respect to the previously calculated magnetic corrections.

   hep-phhep-thNucl.Part.Phys.Proc.(2020)·0 citations
2. 02*

   Dalitz-plot decomposition for the $e^{+}{e}^{-}\to J/\psi \pi \pi (K\bar{K})$ and $e^{+}{e}^{-}\to h_c\pi \pi$ processes

   Viktoriia Ermolina🇩🇪 · Igor Danilkin🇩🇪 · Marc Vanderhaeghen🇩🇪

   We present an analysis of the $e^{+}{e}^{-}\to {\gamma }^{\ast }\to J/\psi \pi \pi (K\bar{K})$ and $e^{+}{e}^{-}\to {\gamma }^{\ast }\to h_c\pi \pi$ processes employing the recently proposed Dalitz-plot decomposition approach, which is based on the helicity formalism for three-body decays. For the above reactions, we validate the factorization of the overall rotation for all decay chains and spin alignments, along with the crossing symmetry between final states, using a Lagrangian-based toy model. For the model-dependent factors that describe the subchannel dynamics, we employ the dispersive treatment of the $\pi \pi (K\bar{K})$ final state interaction, which accurately reproduces pole positions and couplings of the $f_0(500)$ and $f_0(980)$ resonances. The constructed amplitudes serve as an essential framework to further constrain the properties of the charged exotic states $Z_c(3900)$ and $Z_c(4020)$, produced in these reactions.

   hep-phPLB(2025)·2 citations
3. 03*

   Discerning EFTs through multi-Higgs production

   Rafael L. Delgado🇪🇸 · Raquel Gómez-Ambrosio🇮🇹 · Javier Martínez-Martín🇪🇸 · Alexandre Salas-Bernárdez🇪🇸 · Juan J. Sanz-Cillero🇪🇸

   In these proceedings we present the main results of [arXiv:2311.04280 [hep-ph]], where we explore the phenomenological implications of multi-Higgs boson production through longitudinal vector boson scattering within the framework of Effective Field Theories (EFTs). We derive compact expressions for effective tree-level amplitudes involving up to four final-state Higgs bosons. Subsequently, we compute total cross sections for scenarios relevant to the LHC, where we observe that the general Higgs Effective Theory (HEFT) prediction avoids the strong suppression found in the Standard Model Effective Field Theory (SMEFT), typically expected to be several orders of magnitude smaller.

   hep-phPoS(2025)·2 citations
4. 04*

   An experiment to test the isotropy of the one-way speed of light

   Reinaldo J. Gleiser🇦🇷

   An experimental setup capable, in principle, to test the isotropy of the {\em one way} propagation of light to 1 part in $10^8$ (or better), is suggested.

   hep-phgr-qcphysics.class-ph0 citations
5. 05*

   Scaling in the minimal extended seesaw model

   Eito Nagao🇯🇵 · Yuta Hyodo🇯🇵 · Teruyuki Kitabayashi🇯🇵

   The scaling relations in the two-zero textures of the neutrino mass matrices in the minimal extended seesaw mechanism were discovered by Kumar and Patgiri. We demonstrate that some of these scaling relations can be satisfied without requiring two zero elements in the texture.

   hep-phMod.Phys.Lett.A(2025)·1 citation
6. 06*

   Effect of Asymmetric Nuclear Medium on the Valence Quark Structure of the Kaons

   Dhananjay Singh🇮🇳 · Satyajit Puhan🇮🇳 · Navpreet Kaur🇮🇳 · Manpreet Kaur🇮🇳 · Arvind Kumar🇮🇳 · Suneel Dutt🇮🇳 · Harleen Dahiya🇮🇳

   The role of asymmetric nuclear medium on the properties of kaon is investigated at zero and finite temperature employing a hybrid approach integrating the light cone quark model (LCQM) and the chiral SU(3) quark mean field (CQMF) model. The in-medium quark masses are calculated within the CQMF model and are used as inputs to study the medium modifications in the kaon properties. In particular, we have analysed the impact of baryonic density, isospin asymmetry and temperature on the weak decay constant, distribution amplitudes (DAs) and parton quark distributions (PDFs) of valence quark structure of kaons. The effects of isospin asymmetry on the kaon doublet $K=\left(\begin{array}{c}{K}^{+}\\ K^0\end{array}\right)$ and antikaon doublet $\bar{K}$= ($K^{-},{\bar{K}}^0$) are also studied. In order to compare with future experiments, we have also evolved the in-medium DAs and PDFs of kaons to $Q^2=16$ GeV${}^2$. As compared to the temperature and isospin asymmetry, change in baryonic density of the nuclear medium makes more significant changes to the DAs and PDFs of kaons.

   hep-phPRD(2025)·11 citations
7. 07*

   New MiniBooNE excess interpretation using Pseudo-Hermitian neutrino oscillation

   M. L. Abdelali🇩🇿 · N. Mebarki🇩🇿 · B. Boutaghane🇩🇿 · M. Trirat🇩🇿

   The excess observed in the MiniBooNE experiment data has been confirmed by several data releases and analyses. Several attempts to explain this excess have been proposed in the literature, using approaches ranging from experimental errors to new neutrino theories. None of these attempts seem to fully account for the observed excess. In this paper, we present a new approach based on a non-standard two-flavor oscillation theory. In recent years, there has been increasing interest in pseudo-Hermitian Hamiltonian theories and their impact on various quantum phenomena. Neutrino oscillation is modified using the approach of PT-pseudo-Hermitian oscillation, which introduces a zero-distance effect and an asymmetry in the appearance probability of specific flavors. According to this study, such effects can account for the excess and provide a better fit to the data than the current best fit within the standard oscillation framework. We present an analysis of the fit between MiniBooNE data and this new oscillation model.

   hep-phquant-ph0 citations
8. 08*

   Probing a light Higgs in $H\to hh\to b\bar{b}\tau \tau$ in Type-I 2HDM at the LHC

   A. Arhrib🇲🇦 · S. Moretti🇬🇧 · S. Semlali🇬🇧 · C. H. Shepherd-Themistocleous🇬🇧 · Y. Wang🇨🇳 · Q.S. Yan🇨🇳

   In this study, we explore the potential to probe the process $gg\to H_{\text{SM-like}}\to hh\to b\bar{b}\tau \tau$ at the Large Hadron Collider (LHC), within the framework of the Two Higgs Doublet Model (2HDM) Type-I. After performing a detailed Monte Carlo (MC) simulation, we focus on isolating the signal from the Standard Model (SM) backgrounds. Our analysis employs a dedicated trigger choice and optimised kinematic selection to improve the signal sensitivity. We demonstrate some sensitivity to this decay channel at Run 3, while the High-Luminosity LHC (HL-LHC) can provide discovery evidence.

   hep-phPoS(2025)·1 citation
9. 09*

   SIGMA: Single Interpolated Generative Model for Anomalies

   Ranit Das🇺🇸 · David Shih🇺🇸

   A key step in any resonant anomaly detection search is accurate modeling of the background distribution in each signal region. Data-driven methods like CATHODE accomplish this by training separate generative models on the complement of each signal region, and interpolating them into their corresponding signal regions. Having to re-train the generative model on essentially the entire dataset for each signal region is a major computational cost in a typical sliding window search with many signal regions. Here, we present SIGMA, a new, fully data-driven, computationally-efficient method for estimating background distributions. The idea is to train a single generative model on all of the data and interpolate its parameters in sideband regions in order to obtain a model for the background in the signal region. The SIGMA method significantly reduces the computational cost compared to previous approaches, while retaining a similar high quality of background modeling and sensitivity to anomalous signals.

   hep-phcs.LGhep-exphysics.data-anPRD(2025)·8 citations
10. 10*

    Revisiting $KN$ elastic and charge exchange reactions in search of the pentaquark ${\Theta }^{+}$ baryon

    Byung-Geel Yu🇰🇷 · Kook-Jin Kong🇰🇷 · Tae Keun Choi🇰🇷

    In the search for the pentaquark ${\Theta }^{+}$ baryon, the world data on $K^{+}n\to K^{+}n$ and $K^{+}n\to K^{0}p$ reactions on the deuteron target and $K^{0}p\to K^{+}n$ and $K_L^{0}p\to K_S^{0}p$ reactions on the hydrogen target are revisited to study the isoscalar component of the scattering amplitudes. The determination of the $s$- and $p$-wave phase shifts for the two former channels on the deuteron target is presented in the low momentum region with the uncertainty due to the deuteron form factors at forward angles discussed. For the reactions on hydrogen targets, a similarity expected from time reversal between the charge exchange processes $K^{+}n\to K^{0}p$ and $K^{0}p\to K^{+}n$ is exploited, while we present the analysis of the $K_L^{0}p\to K_S^{0}p$ scattering based on the $s$-wave phase shift for low momenta combined with the $t$-channel ${\rho }^0(775)+\omega (782)+\varphi (1020)$ vector meson exchange at high momenta. With the mass 1535 MeV and decay width 5 MeV the possibility of the ${\Theta }^{+}$ in the Breit-Wigner (BW) form is tested in the differential cross section measured by C. J. S. Damerell {\it et\ al.} at ${\mathrm{P}}_{\mathrm{Lab}}=434$ MeV/$c$ and polarization. Our analysis suggests measuring the polarization observable rather than the differential cross section, which has sufficient sensitivity to distinguish the ${\Theta }^{+}$ baryon among all spin and parity states $J^P=1/2^{\pm }$ and $3/2^{\pm }$.

    hep-phnucl-thActa Phys.Polon.B(2025)·0 citations
11. 11*

    Angular observables of the four-fold $B\to K_1(1270,1400)(\to VP){\ell }^{+}{\ell }^{-}$ decays in and beyond the Standard Model

    Faisal Munir Bhutta🇵🇰 · Abdur Rehman🇨🇦 · M. Jamil Aslam🇵🇰 · Ishtiaq Ahmed🇵🇰 · Saadi Ishaq🇵🇰

    Recent measurements of the lepton flavor universality ratios $R_K^{\mu e}$ and $R_{K^{\ast }}^{\mu e}$ in $B\to \left(K,K^{\ast }\right){\mu }^{+}{\mu }^{-}\left(e^{+}{e}^{-}\right)$ at LHCb align with the Standard Model predictions, necessitating search for the complementary decay modes. In this context, we derive the angular decay distributions of the four-fold $B\to K_1(1270,1400)(\to VP){\mu }^{+}{\mu }^{-}$ decays, where $K_1$ is an axial-vector meson, $V=\rho ,K^{\ast }$, and $P=K,\pi$. Considering the weak effective Hamiltonian with vector and axial-vector new physics operators, and employing the helicity formalism, we obtain the four-dimensional differential decay distributions and extract various physical observables. These include differential branching ratios, lepton forward-backward asymmetry, forward-backward asymmetry for transversely polarized $K_1$ meson, longitudinal and transverse polarization fractions of the $K_1$ meson, and the normalized angular coefficients with longitudinally and transversely polarized final state vector meson $V$, in the cascade decay $K_1\to VP$. Based on the latest global fit analysis data for all $b\to s$ transitions, we predict the results of these observables in various bins of the square of the momentum transfer, $q^2$. Our findings indicate that these physical observables are not only sensitive to new physics but can also differentiate between various new physics scenarios in certain kinematical regions. The precise measurements of these observables in $B\to K_1(1270,1400)(\to VP){\mu }^{+}{\mu }^{-}$ decays at current and future experiments will provide opportunities for the complementary searches for physics beyond the Standard Model in $b\to s{\ell }^{+}{\ell }^{-}$ decays.

    hep-phPRD(2025)·6 citations
12. 12*

    Direct detection of Higgs portal for light self-interacting dark matter

    Wu-Long Xu🇨🇳 · Jin Min Yang🇨🇳 · Bin Zhu🇨🇳

    Self-interacting dark matter (SIDM) can address the small-scale anomalies and previous researches focused on such a SIDM heavier than GeV, for which the self-scattering cross-section is in the quantum resonance region and has a non-trivial velocity dependence. For a SIDM lighter than GeV, the self-scattering cross-section falls within the Born region. In this work, considering the constraints from CMB, BBN and the DM relic density, we investigate the direct detection of the Higgs portal for a sub-GeV SIDM with a scalar mediator. For this end, we consider two approaches : one is the cosmic-ray accelerated dark matter (CRDM) scattering off the nucleon, the other is the electron recoil caused by the halo dark matter. We present direct detection limits for the parameter space of light SIDM and scalar mediator. We find that the detectability in either approach needs a sizable mediator-Higgs mixing angle ($\sin \theta$) which is larger than one for the CRDM approach and larger than $10^{-3}$ for the electron recoil approach. While the former case cannot be realized in the Higgs-portal light SIDM model with a scalar mediator, the latter case may also be constrained by some astrophysical observations or beam dump experiment. Anyway, even if other constraints are quite stringent, the direct detection may provide independent limits for such a sub-GeV SIDM.

    hep-phastro-ph.COhep-exEPJC(2025)·7 citations
13. 13*

    Controlling the polarization and vortex charge of $\gamma$ photons via nonlinear Compton scattering

    Jing-Jing Jiang🇨🇳 · Kai-Hong Zhuang🇨🇳 · Jia-Ding Chen🇨🇳 · Jian-Xing Li🇨🇳 · Yue-Yue Chen🇨🇳

    High-energy vortex $\gamma$ photons have significant applications in many fields, however, their generation and angular momentum manipulation are still great challenges. Here, we first investigated the generation of vortex $\gamma$ photons with controllable spin and orbital angular momenta via nonlinear Compton scattering of two-color counter-rotating circularly polarized (CP) laser fields. The radiation probabilities of vortex photons are calculated using the semiclassical approach that resolves angular momenta of emitted photons. We find that the angular momenta transferred to emitted photons are determined by the dominating photon absorption channel, leading to a structured spectrum with alternations in helicity and twist directions. By tuning the relative intensity ratio of the two-color CP laser fields, %the preferred photon absorption channel can be enhanced, providing the polarization and vortex charge of the emitted $\gamma$ photons can be controlled, enabling the generation of circularly polarized vortex $\gamma$ photons with a user-defined polarization and topological charge, which may have a plenty of applications in nuclear physics, astrophysics, particle physics, etc.

    hep-phPRL(2025)·12 citations
14. 14*

    Fluctuations and correlations of quark spin in hot and dense QCD matter

    Hao-Lei Chen🇨🇳 · Wei-jie Fu🇨🇳 · Xu-Guang Huang🇨🇳 · Guo-Liang Ma🇨🇳

    In this work, we examine the impact of QCD phase transitions on the quark spin fluctuations and correlations. We propose the quark-antiquark correlation, which relates to the vector meson spin alignment and the $\Lambda -\bar{\Lambda }$ correlation, can be used as a novel probe of the critical end point (CEP) in the QCD phase diagram. Using the Nambu-Jona-Lanisio model, we qualitatively study the properties of quark-antiquark spin correlations. Our findings reveal a peak structure near the CEP of the chiral phase transition, which may serve as an experimental signature of the CEP and account for the non-monotonic behavior of $\varphi$ meson alignment at low collision energies observed recently in experiments.

    hep-phnucl-exnucl-thPRL(2025)·22 citations
15. 15*

    Exploring twist-3 chiral even generalized parton distributions of light sea quarks in the proton using the light front model

    Parashmani Thakuria🇮🇳 · Madhurjya Lalung🇮🇳 · Jayanta Kumar Sarma🇮🇳

    We develop a light-front model of the proton to investigate the twist-3 chiral-even generalized parton distributions (GPDs) of light sea quarks. In this framework, sea quarks are treated as spin-\(\frac{1}{2}\) active partons, while the remaining proton constituents are modeled as spin-1 spectators. The light-front momentum wave function, derived from the soft-wall AdS/QCD approach, is fitted to unpolarized parton distribution functions (PDFs) from the CETQ global analysis to constrain the model parameters. To further validate the model, we analyze the sea quark flavor asymmetry through the difference \(\bar{d}(x) - \bar{u}(x)\) and the ratio \(\bar{d}(x)/\bar{u}(x)\), achieving good agreement with known phenomenological trends. Using this fitted distribution, we compute the twist-3 chiral-even GPDs and examine their dependence on the transverse momentum transfer \(\boldsymbol{\Delta_T}\) and the longitudinal momentum fraction \(x\). In addition, we evaluate the twist-3 chiral-even PDF \(g_T(x)\) within this framework. The contribution of sea quarks to the proton's orbital angular momentum is also investigated and compared with existing results in the literature.

    hep-phInt.J.Mod.Phys.A(2026)·3 citations
16. 16*

    Transverse spin correlation of back-to-back dihadron in unpolarized collisions

    Lei Yang🇨🇳 · Yu-Kun Song🇨🇳 · Shu-Yi Wei🇨🇳

    The spin correlation of back-to-back dihadron emerges in unpolarized high-energy collision, empowering unpolarized experiments to shed light on the spin-dependent fragmentation functions. This work investigates the transverse spin correlation of back-to-back dihadron in unpolarized $e^{+}{e}^{-}$, $pp$, and $\gamma p$ collisions, which serves as a novel probe of the chiral-odd fragmentation function $H_{1T}(z)$. We compute the transverse spin correlation at the partonic level and establish a connection with helicity amplitudes. Measuring this observable in future experiments can reveal valuable information on the hadronization of transversely polarized quarks.

    hep-phhep-exPRD(2025)·14 citations
17. 17*

    Effects of dark boson mediated feeble interaction between dark matter (DM) and quark matter on $f$-mode oscillation of DM admixed quark stars

    O. P. Jyothilakshmi🇮🇳 · Lakshmi J. Naik🇮🇳 · Debashree Sen🇰🇷 · Atanu Guha🇰🇷 · V. Sreekanth🇮🇳

    We investigate the behavior of the prominent non-radial fundamental $f$-mode oscillations of dark matter (DM) admixed strange quark stars (DMSQSs), by adopting an equation of state (EoS) developed in Ref.~\cite{Sen:2022pfr}, which considers the possible presence of feebly interacting DM in strange quark stars (SQSs) for the first time. Within the model, feeble interaction between fermionic DM $\chi$ and strange quark matter (SQM) is invoked via a vector new physics mediator $\xi$ with coupling strength $y_{\xi }$. The pure SQM is described by the vector MIT Bag model. By varying different EoS parameters, the structural properties viz. the mass, radius and tidal deformability ($\Lambda$) of the DMSQSs are studied with respect to various astrophysical constraints. We study in detail the $f$-mode spectra within the Cowling approximation by obtaining the frequencies as a function of mass, compactness and $\Lambda$ of the star. To the best of our knowledge, this study represents the first analysis of non-radial $f$-mode oscillations of DMSQSs. Our investigation indicates that the presence of DM and its interaction with SQM has great impact on the $f$-modes. We show that the $f$-mode frequencies are larger for DMSQSs, which are largely populated with massive DM fermions, compared to the SQSs. Further, we obtain a linear empirical relation between the $f$-modes and the average density of the star. We also find that the mass-scaled angular frequency varies universally with compactness and $\ln \Lambda$ for DMSQSs. Further, our studies indicate that the inclusion of DM in compact stars reduces the deviation of $f$-mode frequency from general relativistic to Cowling approximation.

    hep-phastro-ph.HEgr-qcnucl-thEPJC(2025)·11 citations
18. 18*

    On Extracting Thermal Parameters and Scenario in High-Energy Collisions

    Ting-Ting Duan🇨🇳 · Sahanaa Büriechin🇨🇳 · Hai-Ling Lao🇨🇳 · Fu-Hu Liu🇨🇳 · Khusniddin K. Olimov🇺🇿

    In this minireview article, we examine the inconsistent results of thermal parameters derived from various models in high-energy collisions. Through a comprehensive literature review and based on the average transverse momentum or the root-mean-square transverse momentum, we propose model-independent parameters to address these inconsistencies. The relevant parameters include: the initial temperature, the effective temperature, the kinetic freeze-out temperature, and the average transverse velocity. Our findings indicate that these four parameters are larger in central collisions, within central rapidity regions, at higher energies, and in larger collision systems. As collision energy increases, excitation functions for all four parameters rise rapidly (slowly) within ranges below (above) approximately 7.7 GeV. At higher energies (>39) GeV, fluctuations occur in trends for these excitation functions, with only slight changes observed in their growth rates. Additionally, this work reveals a mass-dependent multi-temperature scenario pertaining to both initial states and kinetic freeze-out processes.

    hep-phhep-exAdv.High Energy Phys.(2025)·2 citations
19. 19*

    Multi-Jet Production in Deep Inelastic Scattering with Pythia

    Ilkka Helenius🇫🇮 · Joni O. Laulainen🇫🇮 · Christian T. Preuss🇩🇪

    We introduce multi-jet merging for deep inelastic scattering in the Vincia parton shower in the Monte Carlo event generator Pythia 8. Merging combines event samples of different parton multiplicities with logarithmically enhanced parton-shower radiation. We consider up to five outgoing partons using two different merging algorithms. We vary the relevant scale choices and compare to experimental data by H1 collaboration at the HERA collider. Results show that multi-jet merging improves description to data, especially for low virtuality events, and that jet cross-sections converge when the partonic multiplicity exceeds the number of reconstructed jets.

    hep-phJHEP(2025)·4 citations
20. 20*

    Femtoscopy study of ${\pi }^{-}\Lambda$ and $K^{-}p$ interactions

    Pablo Encarnacion🇪🇸 · Albert Feijoo🇩🇪 · Angels Ramos🇪🇸

    We have calculated the femtoscopic correlation functions of meson-baryon pairs in the strangeness $S=-1$ sector, employing a unitarized chiral interaction model up to next-to-leading order. We will show preliminary results for the ${\pi }^{-}\Lambda$ correlation function, which is presently under analysis by the ALICE@LHC collaboration. We will also demonstrate that, within $2\sigma$, the employed interaction is perfectly capable of reproducing the $K^{-}p$ correlation function data measured by the same collaboration, without the need of changing the coupled-channel interactions, as has been suggested recently.

    hep-phPoS(2025)·0 citations
21. 21*

    New constraints on singlet scalar dark matter model with LZ, invisible Higgs decay and gamma-ray line observations

    Yang Yu🇨🇳 · Tian-Peng Tang🇨🇳 · Lei Feng🇨🇳

    The singlet scalar dark matter (DM) model is a minimal extension of the Standard Model (SM). This model features only two free parameters: the singlet scalar mass $m_S$ and the quartic coupling $a_2$ between the singlet scalar and the SM Higgs doublet. Previous studies have suggested that only the resonant region remains viable under combined constraints. In this work, we revisit and refine the constraints using data from the direct detection experiment LZ, invisible Higgs decay measurements, and gamma-ray line observations conducted by Fermi-LAT and DAMPE. Our findings indicate that the latest results from LZ have significantly strengthened the constraints on the model parameters. We demonstrate that only a narrow parameter region remains viable, specifically $60.5\text{GeV}<m_S<62.5\text{GeV}$ and $1.7\times 10^{-4}<a_2<4.7\times 10^{-4}$. This suggests that a three-fold improvement in the current LZ results would thoroughly examine the parameter space below $1\mathrm{TeV}$ for the singlet scalar DM model.

    hep-phastro-ph.HENPB(2025)·6 citations
22. 22*

    Stability of the Scalar Mass against Loop Corrections

    Kang-Sin Choi🇰🇷

    We show that the renormalized loop corrections to the scalar mass are suppressed if the field in the loop is heavy. Here, treating the renormalized mass is important, as it is the only observable. This means that the physics of a low-energy scalar field is insensitive to that of ultraviolet.

    hep-phhep-th6 citations
23. 23*

    Back to the phase space: thermal axion dark radiation via couplings to standard model fermions

    Francesco D'Eramo🇮🇹 · Alessandro Lenoci🇮🇱

    We investigate the cosmological consequences of axion interactions with standard model fermions accurately and precisely. Our analysis is entirely based on a phase space framework that allows us to keep track of the axion distribution in momentum space across the entire expansion history. First, we consider flavor-diagonal couplings to charged leptons and quantify the expected amount of dark radiation as a function of the coupling strength. Leptophilic axions are immune from complications due to strong interactions and our predictions do not suffer from theoretical uncertainties. We then focus on flavor-diagonal interactions with the three heavier quarks whose masses are all above the scale where strong interactions become non-perturbative. The top quark case is rather safe because its mass is orders of magnitude above the confinement scale, and the consequent predictions are solid. The bottom and charm masses are in more dangerous territory because they are very close to the QCD crossover. We present a comprehensive discussion of theoretical uncertainties due to both the choice of the scale where we stop the Boltzmann evolution and the running of QCD parameters. Finally, we compute the predicted amount of dark radiation expressed as an effective number of additional neutrino species. We compare our predictions with the ones obtained via standard approximate procedures, and we find that adopting a rigorous phase space framework alters the prediction by an amount larger than the sensitivity of future CMB observatories.

    hep-phastro-ph.COPRD(2024)·22 citations
24. 24*

    Elastic Dijet Production in Electron Scattering on a Longitudinally Polarized Proton at Small $x$: A Portal to Orbital Angular Momentum Distributions

    Yuri V. Kovchegov🇺🇸 · Brandon Manley🇺🇸

    We calculate the elastic production of dijets from electron collisions with a longitudinally polarized proton target at small values of the Bjorken $x$ variable. Building on the pioneering proposals of \cite{Hatta:2016aoc,Bhattacharya:2022vvo, Bhattacharya:2023hbq, Bhattacharya:2024sck} for measuring the quark and gluon orbital angular momentum (OAM) distributions, our focus is on both the longitudinal double spin asymmetry (DSA) and longitudinal single spin asymmetry (SSA). We compute the numerators of these asymmetries in the small-$x$ formalism of the light-cone operator treatment. Utilizing the small-$x$ expressions for the OAM distributions derived in our earlier paper, we demonstrate that the DSA provides a robust probe for both the quark and gluon OAM distributions within the proton. In contrast, we find that while the SSA is also sensitive to the OAM distributions, extraction of the latter from the SSA would require new developments in small-$x$ theory and phenomenology, and is probably not feasible at this point in time. These findings highlight the potential of DSA measurements in elastic dijet production at the future Electron-Ion Collider to provide the first-ever direct access to the quark and gluon OAM distributions at small $x$, paving the way for new insights into the proton spin puzzle.

    hep-phhep-exnucl-exnucl-thPRD(2025)·16 citations
25. 25*

    Dynamical Axion Misalignment from the Witten Effect

    Abhishek Banerjee🇺🇸 · Manuel A. Buen-Abad🇺🇸

    We propose a relaxation mechanism for the initial misalignment angle of the pre-inflationary QCD axion with a large decay constant. The proposal addresses the challenges posed to the axion dark matter scenario by an overabundance of axions overclosing the Universe, as well as by isocurvature constraints. Many state-of-the-art experiments are searching for QCD axion dark matter with a decay constant as large as $10^{16}\mathrm{GeV}$, motivating the need for a theoretical framework such as ours. In our model, hidden sector magnetic monopoles generated in the early Universe give the axion a large mass via the Witten effect, causing early oscillations that reduce the misalignment angle and axion abundance. As the hidden gauge symmetry breaks, its monopoles confine via cosmic strings, dissipating energy into the Standard Model and leading to monopole-antimonopole annihilation. This removes the monopole-induced mass, leaving only the standard QCD term. We consider the symmetry breaking pattern of $\mathrm{SU}(2{)}^{\prime }\to \mathrm{U}(1{)}^{\prime }\to 1$, leading to monopole and string formation respectively. We calculate the monopole abundance, their interactions with the axion field, and the necessary conditions for monopole-induced axion oscillations, while accounting for UV instanton effects. We present three model variations based on different symmetry breaking scales and show that they can accommodate an axion decay constant of up to $10^{16}\mathrm{GeV}$ with an inflationary scale of $10^{15}\mathrm{GeV}$. The required alignment between monopole-induced and QCD axion potentials is achieved through a modest Nelson-Barr mechanism, avoiding overclosure without anthropic reasoning.

    hep-phJHEP(2025)·7 citations
26. 26*

    Testing the Neutrino Content of the Muon at Muon Colliders

    Rodolfo Capdevilla🇺🇸 · Francesco Garosi🇮🇹 · David Marzocca🇮🇹 · Bernd Stechauner🇨🇭

    Collinear emission of $W$ bosons off a high-energy muon induces a large muon-neutrino component among the Parton Distribution Functions (PDFs) of a muon. In this paper we study the phenomenology related to the ${\nu }_{\mu }$ PDF at future high-energy muon colliders. We examine total rates and differential distributions of the $e{\bar{\nu }}_e$ and $W\gamma$ production processes, which receive a large, and often dominant, contribution from this PDF, allowing for a detailed experimental study. As a demonstration of the impact the ${\nu }_{\mu }$ PDF could have for searches of new physics, we study the charged-current pair production of a couple of heavy states, components of a $\mathrm{SU}(2{)}_L$ doublet. In both $e{\bar{\nu }}_e$ production and charged-current pair production of heavy states, we compare results obtained using PDFs with those of a fixed-order simulation.

    hep-phJHEP(2025)·6 citations
27. 27*

    On sum rules for semi-leptonic $b\to c$ and $b\to u$ decays

    Wen-Feng Duan🇨🇳 · Syuhei Iguro🇯🇵 · Xin-Qiang Li🇨🇳 · Ryoutaro Watanabe🇨🇳 · Ya-Dong Yang🇨🇳

    The semi-leptonic $b\to cl\nu$ processes are receiving a lot of attention, as the lepton flavor universality violation has been hinted by the measured ratios $R_{D^{(\ast )}}=\Gamma (B\to D^{(\ast )}\tau \nu )/\Gamma (B\to D^{(\ast )}\ell \nu )$ for $\ell =e,\mu$. Recently, it has also been pointed out that the baryonic counterpart, $R_{{\Lambda }_c}=\Gamma ({\Lambda }_b\to {\Lambda }_c\tau \nu )/\Gamma ({\Lambda }_b\to {\Lambda }_c\ell \nu )$, has a strong correlation with $R_{D^{(\ast )}}$, referred to as the R ratio sum rule in this paper. The correlation is almost independent of the new physics (NP) contributions and hence can predict $R_{{\Lambda }_c}$ from the measured $R_{D^{(\ast )}}$. On the other hand, we have fewer measurements and/or theoretical studies of the semi-leptonic $b\to ul\nu$ processes, although the same arguments can be applied to the ratios $R_{\pi }$, $R_{\rho }$, and $R_p$ as above. Since these processes are measurable at the ongoing LHCb run-3 and/or Belle~II experiments, precise studies on them are important as well. In this paper, we obtain the semi-analytic formulae for all the aforementioned $R_X$ ratios in the presence of model-independent NP contributions by using the available lattice QCD and/or light-cone sum rule fits to the form factors. Two novel points are highlighted: (i) We evaluate uncertainties of $R_X$ including both the Standard Model (SM) and NP terms, inherited from the form factor fits, and discuss how the uncertainties affect the $R$ ratio sum rules. (ii) We obtain the R ratio sum rule among the semi-leptonic $b\to ul\nu$ processes for the first time, which provides a complementary motivation for observing these processes. In addition, based on our model-independent results, we investigate how the different NP scenarios work in the $b\to c$ and $b\to u$ sectors and perform a combined study in the framework of SM effective field theory with specific flavor symmetries.

    hep-phJHEP(2025)·30 citations
28. 28*

    Thermal Gravitational Waves During Reheating

    Nicolás Bernal🇦🇪 · Yong Xu🇩🇪

    In this work, we revisit the generation of stochastic gravitational waves (GWs) from interactions in the thermal plasma. We extend the existing literature by incorporating the reheating phase into the thermal history. Our results show that the amplitude of the GW spectrum can be significantly enhanced because the temperature during reheating can be much higher than the reheating temperature. Furthermore, since the temperature evolution during reheating differs from that of free radiation, the peak frequency of the spectrum can also shift. Additionally, the morphology of the spectrum can present characteristic features. We also compute the contribution of the integrated GW spectrum to the effective number of neutrino species, $\Delta N_{\text{eff}}$, which can be substantially larger.

    hep-phastro-ph.COJHEP(2025)·27 citations
29. 29*

    Phenomenology of scotogenic-like 3-loop neutrino mass models

    Asmaa Abada🇫🇷 · Nicolás Bernal🇦🇪 · Antonio E. Cárcamo Hernández🇨🇱 · Sergey Kovalenko🇨🇱 · Téssio B. de Melo🇨🇱 · Takashi Toma🇯🇵

    In this talk, we discuss the phenomenology of radiative 3-loop seesaw models. The 3-loop suppression allows the new particles to have masses at the TeV scale, along with relatively large Yukawa couplings, while retaining consistency with neutrino masses and mixing, as observed in neutrino oscillation experiments. This leads to a rich phenomenology, especially in searches for charged lepton flavor violation, where the models predict sizable rates, well within future experimental reach. The models provide viable fermionic or scalar dark matter candidates, as is typical within the scotogenic paradigm. We discuss specific realizations in which the W-mass anomaly and the baryon asymmetry of the Universe can be accommodated, while complying with current constraints imposed by electroweak precision observables, charged-lepton flavor violation and neutrinoless double-beta decay.

    hep-phPoS(2025)·0 citations
30. 30*

    Search for exotic gravitational wave signals beyond general relativity using deep learning

    Yu-Xin Wang🇨🇳 · Xiaotong Wei · Chun-Yue Li🇨🇳 · Tian-Yang Sun🇨🇳 · Shang-Jie Jin🇺🇸 · He Wang🇯🇵 · Jing-Lei Cui🇨🇳 · Jing-Fei Zhang🇺🇸 · Xin Zhang🇺🇸

    The direct detection of gravitational waves by LIGO has confirmed general relativity (GR) and sparked rapid growth in gravitational wave (GW) astronomy. However, subtle post-Newtonian (PN) deviations observed during the analysis of high signal-to-noise ratio events from the observational runs suggest that standard waveform templates, which assume strict adherence to GR, might overlook signals from alternative theories of gravity. Incorporating these exotic signals into traditional search algorithms is computationally infeasible due to the vast template space required. This paper introduces a proof-of-principle deep learning framework for detecting exotic GW signals, leveraging neural networks trained on GR-based templates. Through their generalization ability, neural networks learn intricate features from the data, enabling the detection of signals that deviate from GR. We present the first study evaluating the capability of deep learning to detect beyond-GR signals, including a variety of PN orders. Our model achieves rapid and accurate identification of exotic GW signals across different luminosity distances, with performance comparable to GR-based detections. In particular, applying the model to the GW150914 event demonstrates excellent performance, highlighting the potential of AI-driven methods for detecting previously overlooked signals beyond GR. This work paves the way for new discoveries in gravitational wave astronomy, enabling the detection of signals that might escape traditional search pipelines.

    ↳ gr-qcastro-ph.COhep-phPRD(2025)·8 citations
31. 31*

    Composite running vacuum in the Universe: implications on the cosmological tensions

    Joan Solà Peracaula🇪🇸

    The possibility that the vacuum energy density (VED) could be time dependent in the expanding Universe is intuitively more reasonable than just a rigid cosmological constant for the entire cosmic history. The framework of the running vacuum model (RVM) is a salient example derived from QFT in curved spacetime, wherein the VED appears as a power series of the Hubble rate, $H(t)$, and its derivatives. The RVM contributes to alleviate the cosmological tensions and at a more fundamental level it also helps to smooth out certain hardcore aspects of the cosmological constant problem. Composite dark energy (DE) extensions of the RVM are possible, in which the DE is a mixed fluid made out of running vacuum and an entity X called ``phantom matter'' which, I should stress, is radically different from phantom DE, since the former produces positive pressure like ordinary matter (therein its name). The prototype is the old $\Lambda$XCDM model from 2006. Recently a simplified version of the latter, called the $w$XCDM, has proven capable to yield a truly outstanding fit to the cosmological data with dramatic implications for mitigating the cosmological tensions. The analysis is sensitive to the kind of BAO data used, transversal (2D) or anisotropic (3D). For both BAO types the overall fit quality is substantially better than for the standard $\Lambda$CDM model, and the growth tension becomes alleviated. Nevertheless, only for 2D BAO the $H_0$-tension can be completely cut down. Most notably, this scenario favours (at $3.3\sigma$ c.l.) quintessence-like behavior around our time, as recently reported by the DESI Collaboration. In what follows I will summarize in very simple phenomenological terms the essentials of the RVM idea and its composite extensions, as well as the remarkable practical implications ensuing from such scenarios.

    ↳ astro-ph.COgr-qchep-phhep-th8 citations
32. 32*

    Exploring Intruder Levels of Nuclei (96Zr, 98Zr, 98MO) Within the Framework of IBM-2 Model

    Zainab S. M. · Ali N. Sabbar · Ali Mahdi Abdul Hussein

    Current work includes a study of the very rare case called intruder nuclear levels, where there are only seven nuclei in nature. Such cases occur when the first excited state is . The current study included only three nuclei: . The nuclear model used to explore and investigate nuclei in this work is the second interacting boson. The experimental data and theoretical values obtained were in good agreement, indicating this model's success in calculating such anomalies. The main reason for the presence of these levels in other than their natural locations expected according to the IBM model is that they have a double subshell closure. The values of the electric quadrupole transitions, magnetic dipole transitions and zero transitions estimated were in acceptable agreement with experimental data.

    ↳ nucl-thhep-ph0 citations
33. 33*

    The long-distance window of the hadronic vacuum polarization for the muon g-2

    T. Blum🇺🇸 · P. A. Boyle🇺🇸 · M. Bruno🇮🇹 · B. Chakraborty🇬🇧 · F. Erben🇨🇭 · V. Gülpers🇬🇧 · A. Hackl🇩🇪 · N. Hermansson-Truedsson🇬🇧 · R. C. Hill🇬🇧 · T. Izubuchi🇺🇸 · L. Jin🇺🇸 · C. Jung🇺🇸 and 6 other authors

    We provide the first ab-initio calculation of the Euclidean long-distance window of the isospin symmetric light-quark connected contribution to the hadronic vacuum polarization for the muon $g-2$ and find $a_{\mu }^{\mathrm{LD},\mathrm{iso},\mathrm{conn},\mathrm{ud}}=411.4(4.3)(2.4)\times 10^{-10}$. We also provide the currently most precise calculation of the total isospin symmetric light-quark connected contribution, $a_{\mu }^{\mathrm{iso},\mathrm{conn},\mathrm{ud}}=666.2(4.3)(2.5)\times 10^{-10}$, which is more than 4$\sigma$ larger compared to the data-driven estimates of Boito et al. 2022 and 1.7$\sigma$ larger compared to the lattice QCD result of BMW20.

    ↳ hep-lathep-phPRL(2025)·98 citations
34. 34*

    Collective excitations in the hot QCD medium and the propagation of Heavy Quarks

    Mohammad Yousuf Jamal🇮🇳 · Bedangadas Mohanty🇮🇳

    This review explores the current understanding of collective excitations and the dynamics of heavy quark propagation in the quark-gluon plasma (QGP) formed in relativistic heavy-ion collisions. We focus on three core aspects: the theoretical modelling of the QGP, including momentum anisotropy, medium-induced collisions, finite chemical potential, and non-ideal interactions; the collective behaviours within the plasma; and the interaction dynamics of heavy quarks as they traverse the medium. Along with the polarization energy loss mechanisms, we also review the possibility of energy gain due to thermal field fluctuations. Lastly, we discuss how these theoretical insights can be tested through experiments and outline possible directions for future research.

    ↳ nucl-thhep-phhep-thEPJA(2025)·1 citation
35. 35*

    Hadron interactions and cosmic strings from lattice simulations

    Jorge Baeza-Ballesteros🇪🇸

    This doctoral thesis focuses on the application of lattice techniques to study two separate topics: hadron interactions within quantum chromodynamics (QCD), and the emission of particles and gravitational waves (GWs) from cosmic string loops. The first part of the dissertation deals with the study of two- an three-particle interactions using lattice QCD simulations, complemented by the limit of large number of colors and chiral perturbation theory. In particular, this part presents results on the study of meson interactions as a function of the number of colors, three-pion interactions in chiral perturbation theory, and two- and three-particle scattering in the (1+1)-dimensional O(3) non-linear sigma model. The second part of the thesis is devoted to the study of the dynamics and decay into particles and GWs of cosmic string loops, using classical-field-theory lattice computations. Results are presented for both global and local string loops.

    ↳ hep-latastro-ph.COhep-ph1 citation
36. 36*

    Deep Learning the Forecast of Galactic Cosmic-Ray Spectra

    Yi-Lun Du🇨🇳 · Xiaojian Song · Xi Luo🇨🇳

    We introduce a novel deep learning framework based on Long Short-Term Memory (LSTM) networks to predict galactic cosmic-ray spectra on a one-day-ahead basis by leveraging historical solar activity data, overcoming limitations inherent in traditional transport models. By flexibly incorporating multiple solar parameters, such as the heliospheric magnetic field, solar wind speed, and sunspot numbers, our model achieves accurate short-term and long-term predictions of cosmic-ray flux. The addition of historical cosmic-ray flux data significantly enhances prediction accuracy, allowing the model to capture complex dependencies between past and future flux variations. Additionally, the model reliably predicts full cosmic-ray spectra for different particle species, enhancing its utility for comprehensive space weather forecasting. Our approach offers a scalable, data-driven alternative to traditional physics-based methods, ensuring robust daily and long-term forecasts. This work opens avenues for advanced models that can integrate broader observational data, with significant implications for space weather monitoring and mission planning.

    ↳ astro-ph.HEastro-ph.SRhep-phphysics.space-phApJL(2025)·0 citations
37. 37*

    Consistency of EFT illuminated via relative entropy: A case study in scalar field theory

    Daiki Ueda🇮🇱 · Kazuhiro Tatsumi🇯🇵

    Relative entropy is a non-negative quantity and offers a powerful means of achieving a unified understanding of fundamental properties in physics, including the second law of thermodynamics and positivity bounds on effective field theories (EFTs). We analyze the relative entropy in scalar field theories and show that the non-negativity of relative entropy is potentially violated in perturbative calculations based on operator and loop expansions. Conversely, this suggests that the consistency of the EFT description in the scalar field theory can be identified by the sign of the relative entropy. In fact, we revisit an EFT of single-field inflation and present a relation between its non-linear parameter $f_{\mathrm{NL}}$ and the consistency condition of the EFT description derived from the relative entropy method. We find that interesting regions of $f_{\mathrm{NL}}$ that are observationally allowed can be constrained from the relative entropy by imposing the consistency of the EFT description when the EFT is generated via the interaction with heavy fields in UV theories.

    ↳ hep-thastro-ph.COgr-qchep-ph+1JHEP(2025)·5 citations
38. 38*

    Inferring the Morphology of the Galactic Center Excess with Gaussian Processes

    Edward D. Ramirez🇺🇸 · Yitian Sun🇨🇦 · Matthew R. Buckley🇺🇸 · Siddharth Mishra-Sharma🇺🇸 · Tracy R. Slatyer🇺🇸

    Descriptions of the Galactic Center using Fermi gamma-ray data have so far modeled the Galactic Center Excess (GCE) as a template with fixed spatial morphology or as a linear combination of such templates. Although these templates are informed by various physical expectations, the morphology of the excess is a priori unknown. For the first time, we describe the GCE using a flexible, non-parametric machine learning model -- the Gaussian process (GP). We assess our model's performance on synthetic data, demonstrating that the model can recover the templates used to generate the data. We then fit the \Fermi data with our model in a single energy bin from 2-20 GeV (leaving a spectral GP analysis of the GCE for future work) using a variety of template models of diffuse gamma-ray emission to quantify our fits' systematic uncertainties associated with diffuse emission modeling. We interpret our best-fit GP in terms of GCE templates consisting of an NFW squared template and a bulge component to determine which bulge models can best describe the fitted GP and to what extent the best-fit GP is described better by an NFW squared template versus a bulge template. The best-fit GP contains morphological features that are typically not associated with traditional GCE studies. These include a localized bright source at around $(\ell ,b)=(20^{\circ },0^{\circ })$ and a diagonal arm extending Northwest from the Galactic Center. In spite of these novel features, the fitted GP is explained best by a template-based model consisting of the bulge presented in Coleman et al. (2020) and a squared NFW component. Our results suggest that the physical interpretation of the GCE in terms of stellar bulge and NFW-like components is highly sensitive to the assumed morphologies, background models, and the region of the sky used for inference.

    ↳ astro-ph.HEastro-ph.IMhep-phstat.MLPRD(2025)·10 citations
39. 39*

    What is the Geometry of Effective Field Theories?

    Timothy Cohen🇨🇭 · Xiaochuan Lu🇺🇸 · Zhengkang Zhang🇺🇸

    We elaborate on a recently proposed geometric framework for scalar effective field theories. Starting from the action, a metric can be identified that enables the construction of geometric quantities on the associated functional manifold. These objects transform covariantly under general field redefinitions that relate different operator bases, including those involving derivatives. We present a novel geometric formula for the amplitudes of the theory, where the vertices in Feynman diagrams are replaced by their geometrized counterparts. This makes the on-shell covariance of amplitudes manifest, providing the link between functional geometry and effective field theories.

    ↳ hep-thhep-phPRD(2025)·17 citations
40. 40*

    Field Space Geometry and Nonlinear Supersymmetry

    Yu-Tse Lee🇺🇸

    We propose a geometric formulation of effective field theories via nonlinear supersymmetry. Non-supersymmetric particles are embedded in constrained superfields governed by a nonlinear sigma model, and operators are collected into potentials on the target space. The use of chiral superfields standardizes the treatment of flavor across scalars and fermions, and the minimal jet bundle extension makes invariance under derivative field redefinitions manifest.

    ↳ hep-thhep-phPRD(2025)·11 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.