Fri·Sep 19, 2025Friday·September 19, 2025

1. 01*

   Lepton Collider as a Window to Reheating via Freezing Out Dark Matter Detection

   Subhaditya Bhattacharya🇮🇳 · Anupam Ghosh🇮🇳 · Niloy Mondal🇮🇳 · Abhik Sarkar🇮🇳

   We investigate a particle dark matter (DM) scenario where the DM interaction with the Standard Model are mediated by a leptophilic effective operator. Unlike conventional WIMP scenarios where thermal freeze-out occurs in a radiation-dominated Universe, we consider DM freeze-out during a prolonged reheating epoch driven by inflaton decay. The resulting departure from standard cosmology alters the thermal evolution of the dark matter abundance, making it sensitive to the reheating temperature and the history of entropy injection. The leptophilic nature of the interaction, motivated by the absence of DM signals in the current LHC searches, suppresses couplings to quarks and gluons and instead enables viable DM-lepton interactions that remain largely unconstrained. Within this setup, we analyze the mono-Higgs plus missing energy channel at future lepton colliders where the same operator responsible for setting the relic abundance can be directly probed. We perform a detailed signal-background analysis using both polarized and unpolarized beams. Additionally, our results illustrate how collider experiments, when interpreted jointly with relic density constraints, can provide indirect hints of the Universe's thermal history, offering potential insights into the reheating temperature and the dynamics preceding Big Bang Nucleosynthesis.

   hep-phastro-ph.CO3 citations
2. 02*

   Discovery Prospects for the 150 GeV charged scalar at Future $e^{+}{e}^{-}$ Colliders

   Siddharth P. Maharathy🇿🇦 · Phodiso Maroeshe🇿🇦 · Paballo Ndhlovu🇿🇦 · Srimoy Bhattacharya🇿🇦 · Andreas Crivellin🇨🇭 · Mukesh Kumar🇿🇦 · Rachid Mazini🇿🇦 · Bruce Mellado🇿🇦

   The Real Higgs Triplet model, known as the $\Delta$SM, is a minimal extension of the Standard Model (SM) obtained by adding a hypercharge 0 triplet ($\Delta$). This simple model is motivated by the multi-lepton anomalies and excesses in di-photon, $Z\gamma$, and $WW$ spectra at $\approx 152$ GeV. The model contains, in addition to the SM particle content, a $CP$-even neutral Higgs (${\Delta }^0$) and a charged state (${\Delta }^{\pm }$), which are quasi-degenerate in mass. Observing the charged scalar at the LHC and measuring its mass is very challenging, since it dominantly decays to $WZ$, $tb$, and $\tau \nu$. In this article, we consider the discovery prospects of the charged Higgs with mass 150 GeV at future electron-positron colliders. Taking into account $e^{+}{e}^{-}\to {\gamma }^{\ast },Z^{\ast }\to {\Delta }^{\pm }{\Delta }^{\mp }$ as the production mechanism and the dominant decay modes, we define three signal regions (SR) to study the 150 GeV charged Higgs properties: SR1: $\ge 3j+1\ell$, SR2: $\ge 3\ell +{\tau }_{\text{had}}$, SR3: $\ge 4j+{\tau }_{\text{had}}$. For $m_{{\Delta }^{\pm }}=150\text{ GeV}$, a $5\sigma$ significance can be achieved in SR1 with an integrated luminosity of less than $1{\text{ fb}}^{-1}$. SR2 is very clean with leptonic final states having low background and small systematic uncertainties. Furthermore, SR3 is crucial for reconstructing the charged scalar invariant mass, which can be measured with $\mathcal{O}(1)$ GeV accuracy with an integrated luminosity of $500{\text{ fb}}^{-1}$.

   hep-phEPJC(2026)·1 citation
3. 03*

   Linear seesaw leptogenesis before/after electroweak symmetry breaking

   Yan Shao🇨🇳 · Zhen-hua Zhao🇨🇳

   The linear seesaw (LSS) model provides a natural framework for generating small neutrino masses at low energy scales, thereby offering promising testability prospects. However, in generic LSS models, the exact mass degeneracy (before the electroweak symmetry breaking) between the two sterile neutrinos that form a Dirac pair precludes the generation of CP asymmetries from their interplay, posing a significant challenge to explaining the observed baryon (or lepton) asymmetry of the Universe via the leptogenesis mechanism. In this work, we explore two well-motivated approaches to generate a suitable mass splitting for the two sterile neutrinos that form a Dirac pair, and consequently naturally realize a resonantly enhanced generation of baryon (and lepton) asymmetry. First, we demonstrate that the renormalization group evolution effects can naturally induce the desired mass splitting for the sterile neutrinos, resulting in a successful generation of the observed baryon asymmetry of the Universe. Second, motivated by the recent result from the EMPRESS collaboration that indicates the possible existence of a large lepton asymmetry of the Universe, we explore the possibility that a large lepton asymmetry might naturally follow from the electroweak symmetry breaking which automatically induces the desired mass splitting for the sterile neutrinos.

   hep-phPRD(2025)·1 citation
4. 04*

   Relativistic Atomic Effects of Dark Matter Electron Scattering

   Shao-Feng Ge🇨🇳 · Jie Sheng🇯🇵 · Chuan-Yang Xing🇨🇳

   The dark matter scattering with atomic bound electrons is a crucial avenue for exploring the sub-GeV mass range. The commonly used factorization, where atomic effects are encoded in an overall form factor multiplying the free-electron scattering matrix element, is not necessarily true. Especially, the free-electron kinematics and phase space cannot consistently apply for off-shell bound electrons. Starting from the first principles of quantum field theory, we establish a theoretically consistent formalism to account for the atomic effects. By taking the scalar-type interaction as an example, we investigate the difference between the non-relativistic and relativistic calculations to show that the relativistic effects can lead to a $30\%\sim 50\%$ reduction in the scattering phase space and differential cross section. In other words, not just a theoretically consistent formalism for the atomic effects but also relativistic calculation with Dirac equation are necessary.

   hep-phhep-exEPJC(2026)·5 citations
5. 05*

   Extrapolating Exclusive Charmonium Photoproduction to the Forward Regime Using Gaussian Process

   Xue Wang🇨🇳 · Xu Cao🇨🇳 · Yu Lu🇨🇳 · Weizhi Xiong🇨🇳

   Accessing the forward kinematic regime of exclusive vector meson photoproduction is essential for probing the structure of the proton, yet this region is often experimentally inaccessible. We present a novel extrapolation of near-threshold $\gamma p\to J/\psi p$ differential cross section data to the forward regime $d\sigma /dt{|}_{t=0}$ by applying a non-parametric Gaussian Process (GP) regression. By employing a two-dimensional GP dependent on both the squared momentum transfer $t$ and the center-of-mass energy $W$, we perform a coherent analysis of world data and provide a robust quantification of the extrapolation uncertainties. Furthermore, we apply the GP in the determination of the proton mass radius from the $J/\psi$ photoproduction data. We find that the extracted radius is subject to large systematic uncertainties, highlighting the challenge in precisely constraining this quantity with current experimental precision. This work demonstrates that GP is a powerful and systematic tool for phenomenological studies in hadron physics, particularly for extrapolations into unmeasured kinematic domains.

   hep-phEPJC(2026)·1 citation
6. 06*

   Signature of axion dark matter in low-frequency terrestrial electromagnetic fields: formulation and predictions

   Atsushi Taruya🇯🇵 · Atsushi Nishizawa🇯🇵 · Yoshiaki Himemoto🇯🇵

   We develop a theoretical framework for axion dark matter (DM) searches using terrestrial electromagnetic (EM) fields, enabling a global and quantitative characterization of the signal across the Earth. Axions couple to the geomagnetic field and generate a monochromatic EM signal at a frequency set by the axion mass. Incorporating a realistic atmospheric conductivity, we describe the axion-induced EM waves confined in the Earth-ionosphere cavity, avoiding the divergences present in idealized treatments. Our semi-analytical method yields quantitative predictions for the axion-induced magnetic field near the Earth's surface, and we found that (i) at $m_{\mathrm{a}}\gtrsim 10^{-14}$ eV, the signal exhibits resonance structures aligned with Schumann resonances, and the magnetic field amplitude is especially enhanced at $m_{\mathrm{a}}\sim 3\times 10^{-14}$ eV. (ii) The signal amplitude and orientation also vary with geographic location, with Southeast Asia offering the strongest sensitivity. These predictions are insensitive to uncertainties in conductivity models and boundary conditions. Those distinctive features provide a reliable template to distinguish axion-induced signals from natural or anthropogenic EM backgrounds, and the formalism can be extended to other DM candidates such as dark photons.

   hep-phastro-ph.COPTEP(2026)·5 citations
7. 07*

   Unified Spectroscopic Study of Bottom Mesons and Doubly Bottom Baryons Using a Relativistic Flux-Tube Model

   Pooja Jakhad🇮🇳 · Ajay Kumar Rai🇮🇳

   Using the relativistic flux tube (RFT) model with spin-dependent corrections, we present a unified investigation of the mass spectra for singly bottom mesons ($B$, $B_s$) and doubly bottom baryons (${\Xi }_{bb}$, ${\Omega }_{bb}$). Within this framework, the calculated masses for established $B$ and $B_s$ meson states show excellent agreement with experimental data. Leveraging these reliable predictions for low-lying states, we propose spectroscopic assignments for several higher excitations: we identify the $B_J^{\ast }(5732)$ resonance as an excellent candidate for the $1P(1^{+})$ state; further, we assign the $B_J(5840)$ resonance as the first radial excitation ($2S$), and the $B_J(5970)$ resonance as a $1D$-wave orbital excitation. In the bottom-strange sector, we predict that the recently observed $B_{sJ}(6063)$ and $B_{sJ}(6114)$ resonances belong to the $1D$-wave multiplet. Extending our model to doubly bottom baryons, we present comprehensive predictions for the spectra of the ${\Xi }_{bb}$ and ${\Omega }_{bb}$ baryons, identifying their ground and excited states. These theoretical insights serve as valuable benchmarks, offering guidance for future experimental searches targeting yet-to-be-discovered bottom mesons and doubly bottom baryons.

   hep-phPRD(2025)·8 citations
8. 08*

   Enhancement of Weak Interactions in Phase Transitions in Condensed Matter and Early Universe

   V. V. Flambaum🇦🇺

   Parity-violating weak interactions produce extremely small energy differences between left- and right-handed chiral systems. We show that these microscopic effects may be strongly amplified during collective phenomena such as phase transitions. The enhancement factor is proportional to the critical number of atoms, $N_c$, in the nucleus of the new phase. After the nucleus reaches its critical size, it grows until it fills the entire system. Measurement of the ratio of produced left and right chiral structures may provide a way to measure this critical number $N_c$. Experiments where definite spin-chiral structures are formed during a phase transition in crossed electric and magnetic fields, indicate $N_c\sim 10^9-10^{10}$. An open question is whether a similar enhancement could operate during cosmological phase transitions - thereby boosting CP-violating effects sufficiently to contribute to the observed baryon-to-photon ratio.

   hep-phastro-ph.COcond-mat.otherphysics.atom-ph1 citation
9. 09*

   Exploring CP violation and vanishing electric dipole moment of the electron in a scale-invariant general 2HDM

   Nguyen Dang Bao Nhi🇨🇿 · Eibun Senaha

   We investigate a scale-invariant general two-Higgs-doublet model with explicit CP violation. Using the Gildener-Weinberg method, we analyze the Higgs mass spectrum and couplings at the one-loop level, focusing on CP violation originating from both the Higgs potential and the Yukawa sector. We show that, due to the flatness condition, both CP-even and CP-odd mixings between the 125 GeV Higgs boson and the heavier Higgs states arise only radiatively. As a result, the Higgs couplings to gauge bosons and fermions remain Standard Model-like, in agreement with current LHC constraints. We also find that the magnitude of CP violation from the Higgs potential depends on the new complex Yukawa couplings and heavy Higgs masses, due to the flatness condition. In the case where only an additional top Yukawa coupling ${\rho }_{tt}$ is present, the electron electric dipole moment is directly proportional to $\mathrm{Im}{\rho }_{tt}^2$. Furthermore, a nontrivial cancellation region can occur for a specific Higgs mass spectrum. We extend our analysis to scenarios with an additional complex electron Yukawa coupling, identifying the conditions under which the electron electric dipole moment is suppressed or vanishes.

   hep-phPRD(2026)·5 citations
10. 10*

    Monojet and direct detection constraints on real scalar dark matter: EFT and a simple UV completion

    Arnab Roy🇦🇺 · Michael A. Schmidt🇦🇺 · German Valencia🇦🇺

    We consider constraints that can be placed on certain invisible scalar particles through monojet studies at the LHC and compare them with those from direct detection experiments when interpreted as dark matter. Whereas direct detection constraints are typically more restrictive, we identify regions of parameter space where monojet studies provide important complementary bounds. We carry out our analysis using both a $\varphi$SMEFT for real scalar particle pairs coupled to standard-model fields through operators of up to dimension six, and a simple UV completion with vector-like quarks, with both the scalars and the vector-like quarks being odd under a ${\mathbb{Z}}_2$ symmetry, while the SM particles are even. The vector-like quarks can only decay into a jet and an invisible scalar, and we recast the current ATLAS monojet data to constrain their parameter space. Comparison of the two descriptions yields some insight into interpreting dark matter constraints obtained with EFTs.

    hep-phJHEP(2026)·6 citations
11. 11*

    Fine-grained dark matter substructure and axion haloscopes

    Ciaran A. J. O'Hare🇦🇺 · Giovanni Pierobon🇦🇺

    The velocity distribution of cold dark matter within galaxies is expected to exhibit ultra-fine-grained substructure as a result of the many foldings of an initially smooth phase-space sheet under gravity. The innumerable folds of this sheet in the inner regions of a galactic halo would appear on solar-system scales like an extremely large number of spatially overlapping streams of dark matter particles. Some of these streams may also receive amplified densities if dark matter undergoes enhanced clustering in the early Universe, as is the case for axions in the post-inflationary scenario. This ultra-fine-grained dark matter substructure is usually considered irrelevant and undetectable for most direct detection experiments, but for axion haloscopes, this may not be the case. We develop and explore several plausible models for the degree of fine-grained axion dark matter substructure so as to evaluate its impact on the detectability of axions. We find that not only is this substructure detectable in haloscope experiments, but that it may enhance the detectability of the axion if data is analysed with a high-enough frequency resolution. This conclusion motivates ongoing high-resolution analyses of axion data by haloscope collaborations, which have the potential to reveal evidence of the QCD axion even if their nominal experimental sensitivity does not reach the required level under the Standard Halo Model assumption.

    hep-phastro-ph.COJCAP(2026)·5 citations
12. 12*

    Gluon Polarimetry with Energy-Energy Correlators

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

    We propose a novel method to probe gluon linear polarization via energy correlations in hard scattering processes. This approach exploits the characteristic $\cos 2\varphi$ azimuthal modulation in single- and two-point energy correlations within jets initiated by polarized gluons. In contrast to conventional techniques that rely on $k_t$ resummation or intricate jet substructure observables, our method offers a theoretically robust and experimentally accessible avenue for gluon polarimetry. We perform an all-order analysis within the Ciafaloni-Catani-Fiorani-Marchesini (CCFM) formalism, incorporating coherent branching effects to achieve improved precision. Our predictions can be tested at current and future facilities, including the LHC, RHIC, HERA, and the EIC.

    hep-phhep-exPRL(2026)·22 citations
13. 13*

    Dark Photon Oscillations in Waveguide

    Yu-Xin Tian🇨🇳 · Wenyu Wang🇨🇳 · Wen-Na Yang🇨🇳 · Bin Zhu🇨🇳

    Dark photons, which can kinetically mix with ordinary photons, represent the simplest extension to the standard model. Detecting their oscillations with visible photons could provide crucial insights into the nature of dark matter and fundamental interactions beyond the standard model. We propose a novel laboratory-based approach to detect dark photon oscillations using a laser in an Optical Time-domain Relectometry (OTDR) setup. The laser light propagating through the optical fiber undergoes oscillations with the dark photon, leading to measurable changes in the power flow. These oscillations can precisely measured, leveraging its high sensitivity and efficiency in detecting small variations in the optical signal. This approach could provide a new avenue for probing dark photon oscillations in the laboratory and greatly improve the current experimental sensitivity to dark photon in a wide mass range.

    hep-phhep-thphysics.app-phphysics.optics0 citations
14. 14*

    Melting of heavy quarkonia in QGP using deep neural networks

    Mohammad Yousuf Jamal🇨🇳 · Fu-Peng Li🇨🇳 · Long-Gang Pang🇨🇳 · Guang-You Qin🇨🇳

    Machine learning techniques have emerged as powerful tools for tackling non-perturbative challenges in quantum chromodynamics. In this study, we introduce a data-driven framework employing deep neural networks to systematically predict the temperature-dependent behavior of the screening mass $m_D(T)$ and the strong coupling constant ${\alpha }_s(T)$ within a quark-gluon plasma medium. These medium-sensitive quantities are subsequently employed to compute the thermal widths ${\Gamma }_{\text{n}}(T)$ and binding energies $E_B(T)$ of heavy quarkonia states, specifically charmonia and bottomonia, by numerically solving the Schrödinger equation with medium-modified heavy quark potentials. To estimate the dissociation temperatures $T_d$ of various quarkonia states, we employ two complementary dissociation criteria: the conventional one, where $2E_B(T_d)={\Gamma }_{\text{n}}(T_d)$, and an additional lower bound criterion defined by $E_B(T_d)=3T_d$. This dual-criterion approach provides a more constrained and physically motivated estimate of the temperature range over which quarkonia states dissolve in the QGP environment. Our machine learning-enhanced predictions show excellent agreement with available lattice QCD results, especially for the ground states ${\rm Y}(1S)$ and $J/\psi$, and offer new perspectives on the sequential suppression pattern detected in relativistic heavy-ion collision experiments. Overall, this work advances the quantitative description of quarkonium suppression and demonstrates the prospect of modern machine learning methods to bridge theoretical predictions and experimental observations, thereby contributing significantly to QGP tomography.

    hep-phnucl-thPRC(2026)·3 citations
15. 15*

    Quantum steering and discord in hyperon-antihyperon system in electron-positron annihilation

    Sihao Wu🇨🇳 · Chen Qian🇨🇳 · Qun Wang🇨🇳 · Yang-Guang Yang🇨🇳

    Hyperon-antihyperon pairs produced in high-energy electron-positron annihilation are promising systems for the study of quantum information properties. In this work, we make an analysis of two types of quantum correlations, the quantum steering and discord, in hyperon-antihyperon systems produced in electron-positron annihilation based on the $X$-shaped spin density matrix. The behaviors of these quantum correlations differ from those in elementary particle-antiparticle systems such as the top quark and tau lepton due to the polarization effect. The hierarchy of quantum correlations is examined and partially confirmed in hyperon-antihyperon systems: $\text{Bell Nonlocality}\subset \text{Steering}\subset \text{Entanglement}\subset \text{Discord}$. The loopholes and quantum decoherence effect are also discussed in our work.

    hep-phquant-phPRD(2026)·19 citations
16. 16*

    Multiplicity Distributions and the Frontier between Soft and Hard Physics

    H. R. Martins-Fontes🇧🇷 · F. S. Navarra🇧🇷

    The multiplicity distributions measured in proton proton collisions at the LHC exhibit interesting new features. One of them is the appearance of substructures, such as the so-called "shoulder" at large multiplicities. The most natural interpretation of this behavior is the existence of two production mechanisms. The final result is then a superposition of two distributions. In a previous publication we assumed that the two production mechanisms are soft and semihard partonics scatterings. In this work we further discuss this assumption and, in particular, we study the dependence of the results on the scale which separates soft from hard events.

    hep-phPhysics(2025)·6 citations
17. 17*

    Shedding Light on Dark Matter at the LHC with Machine Learning

    Ernesto Arganda🇪🇸 · Martín de los Rios🇮🇹 · Andres D. Perez🇪🇸 · Subhojit Roy🇺🇸 · Rosa M. Sandá Seoane🇪🇸 · Carlos E. M. Wagner🇺🇸

    We investigate a WIMP dark matter (DM) candidate in the form of a singlino-dominated lightest supersymmetric particle (LSP) within the $Z_3$-symmetric Next-to-Minimal Supersymmetric Standard Model (NMSSM). This framework gives rise to regions of parameter space where DM is obtained via co-annihilation with nearby higgsino-like electroweakinos and DM direct detection~signals are suppressed, the so-called ``blind spots''. On the other hand, collider signatures remain promising due to enhanced radiative decay modes of higgsinos into the singlino-dominated LSP and photons, rather than into leptons or hadrons. Compared to MSSM scenarios with light bino- and wino-like electroweakinos, the NMSSM allows for final states with multiple photons arising from cascade radiative decays, providing a distinctive collider signature. This motivates searches for radiatively decaying neutralinos, however, these signals face substantial background challenges, as the decay products are typically soft due to the small mass-splits ($\Delta m$) between the LSP and the higgsino-like coannihilation partners. We apply a data-driven Machine Learning (ML) analysis that improves sensitivity to these subtle signals, offering a powerful complement to traditional search strategies to discover a new physics scenario. Using an LHC integrated luminosity of $100{\mathrm{fb}}^{-1}$ at $14\mathrm{TeV}$, the method achieves a $5\sigma$ discovery reach for higgsino masses up to $225\mathrm{GeV}$ with $\Delta m\lesssim 12\mathrm{GeV}$, and a $2\sigma$ exclusion up to $285\mathrm{GeV}$ with $\Delta m\lesssim 20\mathrm{GeV}$. These results highlight~the power of collider searches to probe DM candidates that remain hidden from current~direct detection experiments, and provide a motivation for a search by the LHC collaborations using ML methods.

    hep-phcs.LGhep-exPRD(2026)·4 citations
18. 18*

    Hunting the elusive $X17$ in CE$\nu$NS at the ESS

    Joakim Cederkäll🇸🇪 · Yaşar Hiçyılmaz🇹🇷 · Else Lytken🇸🇪 · Stefano Moretti🇬🇧 · Johan Rathsman🇸🇪

    The so-called $X17$ particle has been proposed in order to explain a very significant resonant behaviour (in both the angular separation and invariant mass) of $e^{+}{e}^{-}$ pairs produced during a nuclear transition of excited ${}^8$Be, ${}^4$He and ${}^{12}$C nuclei. Fits to the corresponding data point, as most probable explanation, to a spin-1 object, which is protophobic and has a mass of approximately 16.7 MeV, which then makes the $X17$ potentially observable in Coherent Elastic neutrino ($\nu$) Nucleus Scattering (CE$\nu$NS) at the European Spallation Source (ESS). By adopting as theoretical framework a minimal extension of the Standard Model (SM) with a generic $U(1{)}^{\prime }$ gauge group mixing with the hypercharge one of the latter, which can naturally accommodate the $X17$ state compliant with all available measurements from a variety of experiments, we predict that CE$\nu$NS at the ESS will constitute an effective means to probe this hypothesis, even after allowing for the inevitable systematics associated to the performance of the planned detectors therein.

    hep-phJHEP(2025)·5 citations
19. 19*

    Lepton models from non-holomorphic $A_5^{\prime }$ modular flavor symmetry

    Cai-Chang Li🇨🇳 · Gui-Jun Ding🇨🇳

    In the framework of non-holomorphic modular invariance approach, we have systematically constructed all minimal lepton models based on the non-holomorphic $A_5^{\prime }$ modular symmetry from a bottom-up approach. In these models, the Yukawa couplings are described by polyharmonic Maaß forms of integer weights at level $N=5$. Under the assumption of Majorana neutrinos, both the Weinberg operator and the type-I seesaw mechanism are considered for neutrino mass generation. All minimal models are found to be based on generalized CP (gCP) symmetry, and each of them depends on five real dimensionless parameters and two overall scales. Through comprehensive numerical scanning, we obtain 6 (4) phenomenologically viable Weinberg operator models and 94 (76) phenomenologically viable seesaw models for normal (inverted) ordering neutrino masses. For each viable model, we present predictions for key neutrino properties, such as lepton masses, CP violation phases, mixing angles, effective Majorana mass for neutrinoless double beta decay and the kinematical mass in beta decay. Furthermore, we provide detailed numerical analysis for two representative models to illustrate our results.

    hep-phJHEP(2026)·11 citations
20. 20*

    Towards next-gen parton distribution and fragmentation functions

    Tanishq Sharma🇮🇹

    The interest into parton distribution functions (PDFs) and fragmentation functions (FFs) in current high energy physics research is twofold. On the one hand, they are fundamental objects to conduct precision phenomenology studies, e.g. at the Large Hadron Collider (LHC), to determine the Standard Model parameters and search for new physics. On the other hand, they are also a means to understand the inner structure and dynamics of hadrons, e.g. in regards to the proton spin decomposition at the future Electron Ion Collider (EIC). This thesis presents advancements in PDF and FF determinations contributing to upcoming releases by the NNPDF collaboration. For PDFs, three topics are addressed: (i) assessing the K-factor approximation versus exact NNLO calculations; (ii) evaluating the compatibility of new data with existing PDFs, accounting for all relevant theoretical and experimental uncertainties; and (iii) studying the impact of new data, with focus on processes sensitive to the gluon PDF: single-inclusive jet and di-jet production in proton-proton collisions and deep-inelastic scattering, and top-quark pair production in proton-proton collisions. For FFs, I extend the NNPDF framework through: (i) implementation of time-like evolution in EKO; (ii) extension of PineAPPL to handle multiple convolutions of PDFs and FFs, including the corresponding factorization scales and the polarization of the initial and final states; and (iii) development of a new code, vhf, for computing SIA and SIDIS cross sections. All of these developments are crucial to prepare the release of next-gen PDF and FF sets that will allow us to take advantage of the forthcoming LHC and EIC physics programs as much as possible.

    hep-ph0 citations
21. 21*

    Higgs-like Resonances and Massive Neutrinos in a 3-3-1 Model

    Richard H. Benavides🇨🇴 · D.V. Forero🇨🇴 · Eduardo Rojas🇨🇴 · A. Tapia🇨🇴

    Recent experimental results have reported mild deviations from Standard Model predictions in processes involving two photons in the final state, suggesting the possible presence of high-mass scalar resonances at the few-hundred-GeV scale. We investigate these anomalies within the framework of 3-3-1 models, a well-motivated class of extensions of the Standard Model. Focusing on the most relevant regions of parameter space, we determine the preferred scalar mass ranges and present the results in terms of probability density functions. We implement the 3-3-1 model with right-handed neutrinos, which can be considered as a benchmark within this class of models, in the SARAH package. The scalar sector is constructed from the most general potential involving three Higgs triplets and one scalar sextet, consistent with the required symmetries for a realistic model. The neutrino sector is also analyzed in some detail, where left- and right-handed neutrinos reside in the same leptonic multiplet. Neutrino masses are generated via the Type-I seesaw mechanism, and the Yukawa couplings were constrained employing the Casas-Ibarra parametrization. Finally, we discuss the constraints arising from flavor-changing neutral currents and electroweak precision data.

    hep-phhep-ex0 citations
22. 22*

    Transition Form-Factor for ${\eta }_Q$ at NNLO in the strong coupling ${\alpha }_s$ and with all-order $v^2$ resummation

    Izabela Babiarz🇵🇱 · Chris A. Flett🇫🇷 · Melih A. Ozcelik🇫🇷 · Wolfgang Schäfer🇵🇱 · Antoni Szczurek🇵🇱

    In this work, we discuss both relativistic and perturbative QCD corrections to the transition form-factor ${\mathcal{F}}_{{\eta }_Q}(t_1,t_2)$ for the process ${\gamma }^{\ast }(q_1){\gamma }^{\ast }(q_2)\leftrightarrow {\eta }_Q(P)$ with dependencies on the normalised photon virtualities $t_1=q_1^2/m_Q^2$ and $t_2=q_2^2/m_Q^2$, where $m_Q$ is the heavy quark mass. We resum a class of relativistic corrections to all orders in the relativistic parameter $⟨v^2{⟩}_{{\eta }_Q}$. In addition, we include perturbative QCD corrections up to Next-to-Next-to-Leading Order (NNLO) in the strong coupling constant ${\alpha }_s$. This involves the computation of two-loop amplitudes with two off-shell photons. We explore three different phenomenological applications of our transition form-factors for the charmonium case. We first study the ratio $|{\mathcal{F}}_{{\eta }_c}(t_1,0)|/|{\mathcal{F}}_{{\eta }_c}(0,0)|$ for the single space-like photon case and compare our results with the existing ${\eta }_c$ measurements from the BaBar collaboration. Secondly, we consider observables for the case of double space-like photons and discuss the impact of the different corrections. The NNLO corrections for this case are presented here for the first time in the literature. Finally, we revisit the decay width $\Gamma [{\eta }_c\to \gamma \gamma ]$ and compare it with the existing PDG value.

    hep-phnucl-thEPJC(2025)·4 citations
23. 23*

    Non-invertible Chiral Symmetry and Axions under Electromagnetic Duality

    Gongjun Choi🇺🇸 · Tony Gherghetta🇺🇸 · John Terning🇺🇸

    We study the implications of non-invertible chiral symmetry in a four-dimensional U(1) gauge theory coupled to massless fermions with electromagnetic $SL(2,\mathbb{Z})$ duality. This is done by deriving the Adler-Bell-Jackiw anomaly of massless QED in the dual frame that is used to explicitly construct the symmetry defect operator as well as the conserved two-form symmetry current. As expected, the non-invertible chiral symmetry is covariant under the duality transformation. This has implications for understanding the nature of kinetic and topological terms in the dual frame and for axion electrodynamics. In particular, we show that to generate an axion potential from a dyon loop, the one-form magnetic symmetry must be explicitly broken by a mutually non-local charged state with nonzero pairwise helicity.

    ↳ hep-thhep-phPRD(2025)·6 citations
24. 24*

    Lorentz invariance violation in the extragalactic propagation of ultra-high energy photons and in the development of showers in the Earth crust and atmosphere

    Denise Boncioli🇮🇹 · Valdir Barbosa Bezerra🇧🇷 · Matteo Giammarco🇮🇹 · Iarley Pereira Lobo🇧🇷 · Pedro Morais🇧🇷 · Francesco Salamida🇮🇹

    We investigate the effects of Lorentz invariance violation (LIV) on photon interactions, considering both intergalactic propagation (Breit-Wheeler process) and atmospheric interactions (Bethe-Heitler process). By incorporating LIV into the theoretical framework, we analyze how it modifies key quantities such as the cross section, threshold energy, and mean free path of photons traveling through intergalactic space. In addition, we study its impact on extensive air showers initiated by high-energy photons, demonstrating that LIV can alter the cross section of the primary interaction in the atmosphere. Additionally, we also test the photon interactions in the Earth crust, to evaluate if they can induce upward-going showers. Our results highlight the necessity of accounting for both propagation effects in intergalactic space and interactions in the atmosphere when evaluating LIV signatures. Even small deviations from Lorentz invariance can lead to measurable changes in astroparticle propagation and photon dynamics, offering new opportunities to test quantum gravity theories through high-energy astrophysical observations.

    ↳ astro-ph.HEhep-phPoS(2025)·1 citation
25. 25*

    Searching for Lorentz invariance violation with artificial neural networks

    Tomislav Terzić🇭🇷 · Karlo Mrakovčić🇭🇷

    Lorentz invariance violation (LIV) can have multiple consequences on very-high energy gamma rays' emission, propagation, and detection, such as energy-dependent photon group velocity, photon instability, vacuum birefringence, and modified electromagnetic interaction. Depending on the underlying theoretical model, several of these effects can coexist. Nevertheless, in experimental tests of LIV, each effect is tested separately and independently. Here, we are performing a search for traces of several coexisting effects in a single analysis. We present our analysis method based on artificial neural networks and put our very first results in the context of experimental searches for LIV.

    ↳ astro-ph.HEhep-exhep-phPoS(2025)·1 citation
26. 26*

    Learning Informed Prior Distributions with Normalizing Flows for Bayesian Analysis

    Hendrik Roch🇺🇸 · Chun Shen🇺🇸

    We investigate the use of normalizing flow (NF) models as flexible priors in Bayesian inference via Markov Chain Monte Carlo (MCMC) sampling for iterative Bayesian calibration. Trained on posteriors from previous analyses, these models can be used as informative priors that capture non-trivial distributions and correlations in subsequent inference tasks. We compare different training strategies and loss functions, finding that training based on Kullback-Leibler (KL) divergence and unsupervised learning consistently yield the most accurate reproductions of reference distributions. We apply such a sequential Bayesian workflow to a high-energy nuclear physics problem; MCMC with NF-based priors reproduces the results of one-shot joint inference well, provided the target distributions are unimodal. In cases with pronounced multi-modality or dataset tension, distortions may arise, underscoring the need for caution in multi-stage Bayesian inference. A comparison between the pocoMC MCMC sampler and the standard emcee sampler further demonstrates the importance of advanced and robust algorithms for exploring the posterior space. Overall, our results establish NF-based priors as a practical and efficient tool for sequential Bayesian inference in high-dimensional parameter spaces.

    ↳ nucl-thhep-phPRC(2026)·4 citations
27. 27*

    Heterotic Warm Inflation

    Arjun Berera🇬🇧 · Heliudson Bernardo🇨🇦 · Suddhasattwa Brahma🇬🇧 · Jaime Calderón-Figueroa🇬🇧 · Rudnei O. Ramos🇧🇷 · Michael W. Toomey🇺🇸

    We propose a two-field model of warm inflation motivated by a heterotic string construction, involving an axion and a dilaton-like scalar field with non-trivial kinetic mixing. Gauge-field interactions generate dissipation and thermal corrections affecting both fields. A systematic numerical analysis reveals a range of dynamical regimes, including effectively single-field and multi-field behavior. We find that warm inflation is typically realized along the axion direction, while thermal corrections tend to hinder sustained dilaton-driven inflation over most of the parameter space. Although configurations exist in which the dilaton becomes dynamically relevant, particularly near the end of inflation, the majority of viable solutions are effectively single-field and axion-dominated. These results point to a dynamical mechanism in heterotic-inspired models that naturally favors axion-driven warm inflation while limiting the role of the dilaton.

    ↳ hep-thastro-ph.COgr-qchep-phJHEP(2026)·3 citations
28. 28*

    Global Spin Alignment of (Anti-)${}^4$Li in Non-Central Heavy-Ion Collisions

    Yun-Peng Zheng🇨🇳 · Dai-Neng Liu🇨🇳 · Lie-Wen Chen🇨🇳 · Jin-Hui Chen🇨🇳 · Che Ming Ko🇺🇸 · Yu-Gang Ma🇨🇳 · Kai-Jia Sun🇨🇳 · Jun Xu🇨🇳 · Bo Zhou🇨🇳

    Non-central heavy-ion collisions produce hot and dense nuclear matter with significant fluid vorticity, which can induce global polarizations or alignments of particles with non-zero spins along the direction of the total orbital angular momentum. This phenomenon has been observed for hyperons and vector mesons in experiments. In the present study, we demonstrate that polarized nucleons lead to global spin alignment of the unstable nucleus ${}^4$Li, which can be measured through its strong decays via ${}^4\text{Li}\to {}^3\text{He}+p$. Assuming that ${}^4$Li is formed through the coalescence of polarized nucleons at kinetic freeze-out, we obtain the angular distribution of the daughter particle ${}^3$He in the rest frame of the polarized ${}^4$Li. Taking kinetically freeze-out nucleons from an isotropic and thermalized fireball of constant vorticity and including quantum corrections up to ${\hslash }^2$ in the coalescence calculation through the Moyal star product, we find that the angular distribution of ${}^3$He has a $\cos (2{\theta }^{\ast })$ dependence with ${\theta }^{\ast }$ being its angle with respect to the quantization axis of ${}^4$Li. We also find that the ${}^3$He angular distribution depends on both the vorticity and the polarization of kinetically freeze-out nucleons. Future measurements on the spin alignment of ${}^4$Li in heavy-ion collisions thus offer a promising method to probe the spin dynamics, vortical structure, and spin-dependent equation-of-state of the nuclear matter produced in these collisions.

    ↳ nucl-thhep-phPRC(2026)·7 citations
29. 29*

    Cold and fuzzy dark sector

    Christian Capanelli🇨🇦 · Elisa G.M. Ferreira🇯🇵 · Evan McDonough🇨🇦

    We introduce the Fuzzy Dark Sector (FDS) scenario as a rich, interacting system and candidate for dark matter. This serves as a natural extension of the single-component, non-interacting Fuzzy Dark Matter (FDM) paradigm. Concretely, we consider an ultra-light Abelian-Higgs model, with interacting Higgs and dark photon degrees of freedom. We find that the transfer function, and hence imprint on the CMB and Large-Scale Structure (LSS), is characterized by a single characteristic scale of the interacting fuzzy dark sector, allowing us to recover the LSS signature of single-field FDM, dependent on the FDS parameters. In contrast, galactic halos present a great diversity, unlike with the universality of single-field FDM, owing to the interaction between fields. This interaction introduces an instability that is not otherwise present for the case of four decoupled scalars. Finally, we comment on primordial production and portals to the Standard Model, and introduce another simple realization of the Fuzzy Dark Sector paradigm with a kinetic coupling.

    ↳ astro-ph.COhep-phPRD(2026)·7 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.