Thu·Apr 10, 2025Thursday·April 10, 2025

1. 01*

   The Drell-Yan Process at NNLL${}^{\prime }$+NNLO using Rapidity Dependent Jet Vetoes

   Thomas Clark🇬🇧 · Shireen Gangal🇮🇳 · Jonathan R. Gaunt🇬🇧

   We present results for the Drell-Yan process $pp\to Z/{\gamma }^{\ast }+X\to l^{+}{l}^{-}+X$ in the presence of the rapidity dependent jet vetoes ${\mathcal{T}}_{Bj}$ and ${\mathcal{T}}_{Cj}.$ These observables provide a tighter veto at central rapidities than at forward rapidities. Our predictions contain a resummation of large logarithms of the veto scale over the hard scale, matched to fixed order in perturbation theory; we present results at both NLL${}^{\prime }$+NLO and NNLL${}^{\prime }$+NNLO. Uncertainty estimates are provided that contain both resummation and fixed-order uncertainties; we find that using a standard profile scale variation procedure for the former seems to underestimate the uncertainty, particularly at NLL${}^{\prime }$+NLO. Consequently, we modify the procedure to avoid cancellation of scale variations between partonic channels, and verify that the uncertainties from this method are reasonable using a simplified version of the Theory Nuisance Parameter (TNP) method. We then find that the uncertainty decreases going from the NLL${}^{\prime }$+NLO to the NNLL${}^{\prime }$+NNLO predictions, and obtain an uncertainty at the level of $1-3\%$ in the NNLL${}^{\prime }$+NNLO predictions when the veto scale is of $\mathcal{O}(10\text{ GeV})$.

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

   Mesons, baryons and the confinement/deconfinement transition

   V. Tomas Mari Surkau🇫🇷 · Urko Reinosa🇫🇷

   We identify an observable that could operate as a probe of the quark versus hadron content of a bath of quarks and gluons at finite temperature and chemical potential. To this purpose, we relate the Polyakov and anti-Polyakov loops, which determine how energetically costly it is to bring an external static quark or antiquark probe into the thermal bath, to the ability of that medium to provide favorable conditions for the formation of meson-like or baryon-like configurations that would screen the probes.

   hep-phhep-thPLB(2026)·3 citations
3. 03*

   Three-Loop QCD corrections to the production of a Higgs boson and a Jet

   Xiang Chen🇨🇭 · Xin Guan🇺🇸 · Bernhard Mistlberger🇺🇸

   We compute three-loop QCD corrections to the scattering amplitude of a Higgs boson and three partons interfered with its tree level counterpart. Specifically, we derive our results in the generalized leading color limit. Our results are represented in terms of so-called multiple polylogarithms and thus ready for use in phenomenological predictions. We provide the three-loop amplitudes necessary to compute the production cross section of a Higgs boson and a hadronic jet at hadron colliders and the decay probability of a Higgs boson to three hadronic jets at lepton colliders.

   hep-phhep-thPRD(2026)·17 citations
4. 04*

   Axionless Solution to the Strong CP Problem -- two-zeros textures of the quark and lepton mass matrices and neutrino CP violation --

   Morimitsu Tanimoto🇯🇵 · Tsutomu T. Yanagida🇯🇵

   CP invariance is a very attractive solution to the strong CP problem in QCD. This solution requires the vanishing $\arg [\det M_d\det M_u]$, where the $M_d$ and $M_u$ are the mass matrices for the down- and up-type quarks. It happens if we have several zeros in the quark mass matrices. We proceed a systematic construction, in this paper, of two zeros textures for the down-type quark mass matrix while the mass matrix for the up-type quarks is always diagonal. We find only three types of the mass matrices can explain the observed CKM matrix, the masses of the quarks and the charged leptons and the small enough vacuum angle $\theta <10^{-10}$. We extend the mass construction to the neutrino sector and derive predictions on the CP violating parameter ${\delta }_{CP}$ in the neutrino oscillation and the mass parameter $m_{\beta \beta }$. It is extremely remarkable that the normal (NH) and inverted (IH) hierarchies in the neutrino masses are equally possible in the case where we introduce only two right-handed neutrinos $N$s. Furthermore, we have a strict prediction on the ${\delta }_{CP}\simeq 200^{\circ }$ or $250^{\circ }$ in the NH case. If it is the case we can naturally explain the positive sign of the baryon asymmetry in the present universe.

   hep-phPTEP(2025)·2 citations
5. 05*

   Searching for the dark photon at the Future Circular Lepton Collider

   X. G. Wang🇦🇺 · A. W. Thomas🇦🇺

   In the context of future electroweak precision measurements at the Future Circular Lepton Collider (FCC-ee), we consider recent proposals aimed at finding signatures of physics beyond the Standard Model. In particular, we focus on recent novel suggestions for very precise direct measurements of ${\alpha }_{\mathrm{em}}(M_Z^2)$. It is shown that at a level of precision of order $10^{-5}$, the effects of a dark photon may be very significant.

   hep-phhep-exPLB(2025)·2 citations
6. 06*

   Hunting axion dark matter signatures in low-frequency terrestrial magnetic fields

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

   We show that Earth's natural environment can serve as a powerful probe for ultralight axion dark matter. In the presence of global geomagnetic fields, the axions with masses ranging from $10^{-15}\mathrm{eV}-10^{-13}\mathrm{eV}$ induce electromagnetic waves in the (sub-) extremely low-frequency band ($0.3-30\mathrm{Hz}$) through the axion-photon coupling. We predict the amplitude of induced magnetic fields in the Earth-ionosphere cavity, taking the finite conductivity of the atmosphere into account. This allows us to constrain the axion-photon coupling parameter, $g_{\mathrm{a}\gamma }$, from the long-term monitoring data of the low-frequency magnetic fields, resulting in a significant improvement from the previous constraints down to $g_{\mathrm{a}\gamma }\lesssim 4\times 10^{-13}{\mathrm{GeV}}^{-1}$ for axion mass $\sim 3\times 10^{-14}\mathrm{eV}$.

   hep-phastro-ph.COPTEP(2025)·10 citations
7. 07*

   Machine Learning in the Hunt for Heavy Charged Higgs Bosons at Gamma-Gamma Colliders in the Type III Two Higgs Doublet Model

   Ijaz Ahmed🇵🇰 · Abdul Quddus🇵🇰 · Jamil Muhammad🇰🇷 · M. A. Arroyo-Ure🇲🇽

   We conduct a detailed exploration of charged Higgs boson masses $M_{H^{\pm }}$ within the range of $100-190GeV$. This investigation is grounded in the benchmark points that comply with experimental constraints, allowing us to systematically account for uncertainties inherent in the analysis. Our results indicate significant production prospects for the process $H^{+}{H}^{-}\to \tau {\nu }_{\tau }\tau {\nu }_{\tau }$, which could provide essential insights into the properties of $H^{\pm }$ bosons. By examining these decay channels, we aim to illuminate the interplay between the charged Higgs boson and the established Standard Model. The research uses machine learning methods like Boosted Decision Trees (BDT) and Multilayer Perceptrons (MLP), as well as Likelihood and LikelihoodD, to improve the identification of heavy charged Higgs bosons compared to Standard Model backgrounds at a 3.0 TeV $\gamma \gamma$ collider with an integrated luminosity of ${\mathcal{L}}_{int}=3000f{b}^{-1}$.

   hep-ph0 citations
8. 08*

   Les Houches 2023 -- Physics at TeV Colliders: Report on the Standard Model Precision Wishlist

   Alexander Huss🇨🇭 · Joey Huston🇺🇸 · Stephen Jones🇬🇧 · Mathieu Pellen🇩🇪 · Raoul Röntsch🇮🇹

   Les Houches returned to an in-person format in 2023 and the bi-yearly tradition of updating the standard model precision wishlist has continued. In this work we review recent progress (since Les Houches 2021) in fixed-order computations for LHC applications. In addition, necessary ingredients for such calculations such as parton distribution functions, amplitudes, and subtraction methods are discussed. Finally, we indicate processes and missing higher-order corrections that are required to reach the theoretical accuracy that matches the anticipated experimental precision.

   hep-phhep-exSciPost Phys.Comm.Rep.(2026)·28 citations
9. 09*

   Axion-like particle production from lepton-nucleon scattering in chiral effective theory

   Qian-Qian Guo🇨🇳 · Xiong-Hui Cao🇨🇳 · Zhi-Hui Guo🇨🇳 · Hai-Qing Zhou🇨🇳

   In this work we study the axion/axion-like particle production from the lepton-nucleon scattering in the low-energy region, i.e., the $\ell N\to \ell Na$ processes, $\ell$ being the electron or muon and $N$ the proton or neutron. We simultaneously include three different types of axion interaction couplings within the chiral effective field theory, namely the axion-nucleon-nucleon couplings $g_{aNN}$, axion-photon-photon coupling $g_{a\gamma \gamma }$ and axion-photon-vector meson resonances couplings $g_{\rho a\gamma }$ and $g_{\omega a\gamma }$. Vast inputs from the lattice QCD and hadron phenomenological studies are used to fix the unknown couplings. The relative strengths of different axion interactions in the $\ell N\to \ell Na$ processes are then revealed. We provide detailed predictions for the differential cross sections with respect to various angles and axion energy, as well as the total cross sections in the low-energy region around production thresholds, both for the Kim-Shifman-Vainstein-Zakharov (KSVZ) and Dine-Fischler-Srednicki-Zhitnitsky (DFSZ) axion models.

   hep-phPRD(2026)·2 citations
10. 10*

    Investigation of triply heavy spin-3/2 baryons in their ground and excited states

    Z. Rajabi Najjar🇮🇷 · K. Azizi🇮🇷

    We calculate the masses and residues of triply heavy baryons with spin-3/2, including ${\Omega }_{ccc}^{\ast }$, ${\Omega }_{ccb}^{\ast }$, ${\Omega }_{bbc}^{\ast }$ and ${\Omega }_{bbb}^{\ast }$, using the QCD sum rules method. Our calculations primarily focus on obtaining the masses of the first three resonances, that is, the ground state (1S), the first orbital excited state (1P), and the first radial excited state (2S), for the mentioned baryons. We additionally determine the residues of these baryons, which serve as key parameters for studying their possible decay channels and interactions with other particles. To achieve higher accuracy compared to previous studies, we consider nonperturbative operators up to eight mass dimensions. We present our calculated outcomes in two distinct energy schemes, referred to as pole and $\overline{\mathrm{MS}}$. Given the absence of experimental data for these states, we compare our results with previous theoretical calculations that are reported in relevant studies employing various approaches. These results may provide valuable insights for experimental groups searching for the triply heavy baryons.

    hep-phhep-exhep-latPLB(2025)·6 citations
11. 11*

    New physics particles mixing with mesons: production in the fragmentation chain

    Yehor Kyselov🇺🇦 · Stephen Mrenna🇺🇸 · Maksym Ovchynnikov🇨🇭

    A class of extensions to the Standard Model adds hypothetical long-lived particles (LLPs) that have mass- or kinetic-mixing with neutral mesons, such as pions or rho mesons. The mixing can contribute significantly to the production of LLPs at proton accelerator experiments, and no consistent description of these production modes exists in the literature. In this paper, we develop a framework for studying different LLPs - dark photons, vector mediators coupled to the baryon current, and axion-like particles with different coupling patterns. In particular, we implement the production mechanisms in \texttt{PYTHIA8}, study how the overall flux and kinematic distributions depend on the LLP's mass, and compare various sub-processes where the mixing contributes - proton bremsstrahlung, meson decay, and production in the fragmentation chain. We find that our new description of LLP production predicts an integrated flux that differs from current approaches by one to two orders of magnitude, and highlight the unavoidable theoretical uncertainties coming from poor knowledge of the properties of heavy mesons.

    hep-phPRD(2025)·7 citations
12. 12*

    High-order fluctuations of temperature in hot QCD matter

    Jinhui Chen🇨🇳 · Wei-jie Fu🇨🇳 · Shi Yin🇩🇪 · Chunjian Zhang🇨🇳

    A new thermodynamic state function is introduced to describe the thermodynamics relevant for the mean transverse momentum fluctuations of charged particles in heavy-ion collisions, which allows us to compute the temperature fluctuations of different orders in hot quantum chromodynamics (QCD) matter for the first time. Consequently, it is found that the temperature fluctuations are suppressed remarkably as the system transitions from the hadron resonance gas (HRG) to the quark-gluon plasma (QGP) with increasing temperature or baryon chemical potential, alongside a negative skewness. This is attributed to the general fact that the heat capacity of QCD matter increases significantly in QGP in comparison to that in HRG. These predictions provide a candidate observable to discover the thermodynamic temperature fluctuations in upcoming heavy-ion collision experiments, which also paves a novel way to study QCD thermodynamics and QCD phase diagram through measurements of the mean transverse momentum fluctuations of charged particles.

    hep-phnucl-exnucl-thPRD(2026)·11 citations
13. 13*

    Decays $\tau \to \pi \pi \eta {\nu }_{\tau }$ and $\tau \to \pi \eta \eta {\nu }_{\tau }$ in the extended Nambu-Jona-Lasinio model

    M.K. Volkov🇷🇺 · A.A. Pivovarov🇷🇺 · K. Nurlan🇷🇺

    In the framework of the extended Nambu-Jona-Lasinio model, the processes $\tau \to \pi \pi \eta ({\eta }^{\prime }){\nu }_{\tau }$ and $\tau \to \pi \eta \eta ({\eta }^{\prime }){\nu }_{\tau }$ are considered taking into account mesons in the ground and first radially excited intermediate states. It is shown that in the processes $\tau \to \pi \pi \eta ({\eta }^{\prime }){\nu }_{\tau }$ the vector channel is dominant, and in the processes $\tau \to \pi \eta \eta ({\eta }^{\prime }){\nu }_{\tau }$ the main contribution is given by the axial vector channel. The scalar meson $a_0$ plays a dominant role in processes with two $\eta$-mesons in the final state. The significance of the relative phase between the ground and first radially excited states for these processes is shown. The obtained results for the $\tau \to \pi \pi \eta {\nu }_{\tau }$ process are in satisfactory agreement with the recent experimental data from BaBar and CMD-3, which differ from the averaged values given in the PDG tables.

    hep-phNatural Sci.Rev.(2025)·0 citations
14. 14*

    Scattering and gluon emission of physical quarks in a SU(3) colored field

    Meijian Li🇪🇸 · Tuomas Lappi🇫🇮 · Xingbo Zhao🇨🇳 · Carlos A. Salgado🇪🇸

    We study the scattering of the gluon-dressed physical quarks, defined as the eigenstates of the vacuum QCD Hamiltonian, off a colored medium. We solve the wavefunction of the physical quark state by diagonalizing the QCD Hamiltonian in vacuum in a $|q⟩+|qg⟩$ Fock space, with implementing the sector-dependent mass renormalization scheme. We then perform numerical simulations of the real-time quantum state evolution of the initially dressed quark state at various medium densities. The results are compared with those of an initially bare or off-shell quark states. With the obtained light-front wavefunction of the evolved state, we extract the quark jet transverse momentum broadening, the quenching parameter, the cross section, the gluon emission rate, and the evolution of the invariant mass. The scenario considered is relevant for high energy scattering processes, where the quark originates from far outside the color field describing the scattering target. This investigation on dressed quarks complements our earlier studies of the single quark scattering in the $|q⟩$ Fock space, and of the bare quark scattering in the $|q⟩+|qg⟩$ Fock space, providing a novel systematic description of quark scattering process using a non-perturbative formalism.

    hep-phnucl-thPRD(2025)·7 citations
15. 15*

    A Robust Determination of Antinuclei Production from Dark Matter via Weakly Decaying Beauty Hadrons

    Mattia Di Mauro🇮🇹 · Adil Jueid🇰🇷 · Jordan Koechler🇮🇹 · Roberto Ruiz de Austri🇪🇸

    Recently, the Alpha Magnetic Spectrometer (AMS-02) Collaboration presented tentative evidence for the detection of cosmic antihelion-3 (${}^3\overline{\mathrm{He}}$) events, alongside a comparable number of antideuterons ($\overline{\mathrm{D}}$). If confirmed, these observations could revolutionize our understanding of cosmic-ray production and propagation and/or serve as compelling indirect evidence for dark matter. Given that the detection of cosmic $\overline{\mathrm{D}}$ is already at the limit of AMS-02 sensitivity, explaining the observation of ${}^3\overline{\mathrm{He}}$ even within the standard coalescence framework poses a significant challenge. It has recently been shown that a previously overlooked mechanism within the Standard Model of particle physics-namely, the production of antihelion via the displaced-vertex decay of ${\bar{\Lambda }}_b^0$ baryons-could substantially enhance the ${}^3\overline{\mathrm{He}}$ flux arising from dark matter-induced processes. In light of these challenges, we present a tuning of Pythia that is consistent with LEP data on the fragmentation function of $b$ quarks into $b$-hadrons-a critical factor for determining the ${\bar{\Lambda }}_b^0$ multiplicity-and with ALICE and ALEPH data for the $\overline{\mathrm{D}}$ and ${}^3\overline{\mathrm{He}}$ spectra, which we employ to determine our coalescence model. Our refined Pythia tuning, in conjunction with our coalescence model, results in a predicted branching ratio for the production of ${}^3\overline{\mathrm{He}}$ from ${\bar{\Lambda }}_b^0$ decays that is consistent with the recent upper limit measured by LHCb. Furthermore, our prediction indicates that the contribution of $\overline{\mathrm{D}}$ and ${}^3\overline{\mathrm{He}}$ from beauty-hadron decays is negligible relative to the direct production from hadronization.

    hep-phastro-ph.HEPRD(2025)·9 citations
16. 16*

    Primordial neutrinos fade to gray: constraints from cosmological observables

    Gabriela Barenboim🇪🇸 · Julien Froustey🇺🇸 · Cyril Pitrou🇫🇷 · Hector Sanchis🇪🇸

    We investigate the effect of potentially large distortions of the relic neutrino spectra on cosmological observables. To that end, we consider a phenomenological model of "gray" spectral distributions, described by a single parameter, which generalizes the traditional $y$-distortions to possibly large negative values. Implementing these distortions in the primordial nucleosynthesis code PRIMAT, we can constrain the distortion parameter along with the presence of extra radiation, exploiting the complementarity of big bang nucleosynthesis and cosmic microwave background measurements to disentangle gravitational and non-thermal effects. These constraints rule out a distortion where more than $\sim 1/2$ of the neutrinos' energy density is replaced by dark radiation. Nonetheless, we find that large distortions, accompanied with extra radiation, are allowed-and even slightly preferred in some cases-by current cosmological observations. As this scenario would require substantial modifications to the physics of neutrino decoupling in the early Universe, these observational constraints call for a renewed attention on the possibility of large deviations from the standard cosmological model in the neutrino sector.

    hep-phastro-ph.COPRD(2025)·7 citations
17. 17*

    Prospects for detecting new dark physics with the next generation of atomic clocks

    Benjamin Elder🇬🇧 · Giorgio Mentasti🇬🇧 · Elizabeth Pasatembou🇬🇧 · Charles F. A. Baynham🇬🇧 · Oliver Buchmueller🇬🇧 · Carlo R. Contaldi🇬🇧 · Claudia de Rham🇬🇧 · Richard Hobson🇬🇧 · Andrew J. Tolley🇬🇧

    Wide classes of new fundamental physics theories cause apparent variations in particle mass ratios in space and time. In theories that violate the weak equivalence principle (EP), those variations are not uniform across all particles and may be detected with atomic and molecular clock frequency comparisons. In this work we explore the potential to detect those variations with near-future clock comparisons. We begin by searching published clock data for variations in the electron-proton mass ratio. We then undertake a statistical analysis to model the noise in a variety of clock pairs that can be built in the near future according to the current state of the art, determining their sensitivity to various fundamental physics signals. Those signals are then connected to constraints on fundamental physics theories that lead directly or indirectly to an effective EP-violating, including those motivated by dark matter, dark energy, the vacuum energy problem, unification or other open questions of fundamental physics. This work results in projections for tight new bounds on fundamental physics that could be achieved with atomic and molecular clocks within the next few years. Our code for this work is packaged into a forecast tool that translates clock characteristics into bounds on fundamental physics.

    hep-phgr-qcphysics.atom-phPRD(2025)·10 citations
18. 18*

    Constraining Mixed Dark Matter models with high redshift Lyman-alpha forest data

    Olga Garcia-Gallego🇬🇧 · Vid Iršič🇬🇧 · Martin G. Haehnelt🇬🇧 · Matteo Viel🇮🇹 · James S. Bolton🇬🇧

    This study sets new constraints on Cold+Warm Dark Matter (CWDM) models by leveraging the small-scale suppression of structure formation imprinted in the Lyman-$\alpha$ forest. Using the Sherwood-Relics suite, we extract high-fidelity flux power spectra from simulated Lyman-$\alpha$ forest data, spanning a broad range of cosmologies and thermal histories. This enables precise constraints on the warm dark matter (WDM) fraction, $f_{\mathrm{WDM}}$, and the mass of the WDM particle, $m_{\mathrm{WDM}}$. A key advancement of our analysis is the integration of a neural network emulator directly at the likelihood level, significantly accelerating Bayesian parameter inference. With new observations of high-redshift ($z$ = 4.2$-$5.0) quasar spectra from UVES and HIRES, we establish stringent upper limits: for $m_{\mathrm{WDM}}$ = 1 keV, we find $f_{\mathrm{WDM}}<0.16$ (2$\sigma$), with constraints loosening to 35\%, 50\%, and 67\% for $m_{\mathrm{WDM}}$ = 2, 3, and 4 keV, respectively. Our results for pure WDM reaffirm the lower bounds of previous work. Crucially, we account for the fixed resolution of simulations and the impact of patchy reionization, demonstrating their minimal influence on mixed dark matter constraints. This robustness paves the way for tighter bounds with improved statistical samples in the future. Our findings suggest that CWDM models can naturally accommodate mild suppression of matter clustering in the high redshift Lyman-$\alpha$ forest 1D flux power, potentially offering a resolution to some of the ongoing cosmological tensions at low redshifts, namely the $S_8$ tension.

    ↳ astro-ph.COhep-phhep-thPRD(2025)·31 citations
19. 19*

    Non Nucleonic Components in Short Nuclear Distances

    Misak M Sargsian

    One of the important features of nuclear forces is their strong repulsive nature at short ($\le 0.5-0.6$~Fm) distances which prevents atomic nuclei from collapsing, thus guarantying the stability for the visible matter. However the dynamical nature of this repulsion (referred to as a nuclear core) is as elusive as ever. We present the study of nuclear dynamics at extremely large internal momenta in the deuteron dominated by the nuclear core. It is demonstrated that the paradigm shift in the description of the deuteron consisting of proton and neutron to the description of the deuteron as a pseudo-vector composite system in which proton and neutron is observed in high energy electro-disintegration processes results in the emergence of a new structure. We demonstrate that this new structure can exist only if it emerges from pre-existing non-nucleonic component in the deuteron. The study of the dynamics of the predicted new structure is presented focusing on the question if it allows to understand the anomaly observed in the recent experiment at Jefferson Lab that probed deuteron structure at internal momenta above 800 MeV/c.

    ↳ nucl-thhep-phnucl-exPoS(2025)·0 citations
20. 20*

    Graviton stimulated emission in squeezed vacuum states

    Atsuhisa Ota🇨🇳 · Yuhang Zhu🇰🇷

    We study the dynamics of gravitons in a squeezed vacuum state under a thermal radiation background. Unlike traditional treatments that rely on the Boltzmann equation, we employ the Heisenberg equation and average it over general quantum states. In contrast to the usual Boltzmann-based descriptions, our approach captures the subtleties arising from quantum coherence in different number eigenstates, which is essential for soft graviton modes in the squeezed vacuum state. Our new method successfully reproduces the previous one-loop results within the in-in formalism when the expansion parameter is small and deviates significantly as the parameter increases, indicating that our results extend beyond the one-loop in-in formalism. We examine the implications of graviton emission effects stimulated by quantum coherence in both flat and expanding backgrounds. In the flat background, it is found that backreaction of radiation on the spacetime dynamics is crucial for significant stimulated emission. In the expanding background, to avoid the subtleties associated with superhorizon modes, we investigate the effect of emission within the horizon immediately after reheating and find a significant effect. We also examined the IR graviton evolution from a symmetry perspective and propose a regularization prescription to eliminate the secular growth problem.

    ↳ hep-thastro-ph.COgr-qchep-phPRD(2025)·7 citations
21. 21*

    SHiP experiment at the SPS Beam Dump Facility

    SHiP Collaboration · HI-ECN3 Project Team

    In 2024, the SHiP experiment, together with the associated Beam Dump Facility (BDF) under the auspices of the High Intensity ECN3 (HI-ECN3) project, was selected for the future physics exploitation of the ECN3 experimental facility at the SPS. The SHiP experiment is a general-purpose intensity-frontier setup designed to search for physics beyond the Standard Model in the domain of Feebly Interacting Particles at the GeV-scale. It comprises a multi-system apparatus that provides discovery sensitivity to both decay and scattering signatures of models with feebly interacting particles, such as dark-sector mediators, both elastic and inelastic light dark matter, as well as millicharged particles. The experiment will also be able to perform both Standard Model measurements and Beyond Standard Model searches with neutrino interactions. In particular, it will have access to unprecedented statistics of tau and anti-tau neutrinos. The construction plan foresees commissioning of the facility and detector, and start of operation in advance of Long Shutdown 4, with a programme of exploration for 15 years of data taking. By exploring unique regions of parameter space for feebly interacting particles in the GeV/c${}^2$ mass range, the SHiP experiment will complement ongoing searches at the LHC and searches at future colliders.

    ↳ hep-exhep-ph29 citations
22. 22*

    Universal profile for cosmic birefringence tomography with radio galaxies

    Fumihiro Naokawa🇯🇵

    We propose a new method to tomographically probe cosmic birefringence using radio galaxies. We show that the redshift evolution of the cosmic birefringence angle induced by a slow-rolling pseudoscalar field, which is a candidate for dynamical dark energy, is independent of the detailed model of the pseudoscalor field. This universal profile evolves predominantly at $z\lesssim 10$. In contrast, if the origin is a dark matter-like pseudscalor field, the resulting birefringence angle tends to be negligible in the low-redshift regime. This new insight provides a strong motivation to independently test the cosmic birefringence using polarized astrophysical sources such as radio galaxies. We find that a sample size of $\text{order}10^5-10^6$ is required to distinguish the profiles, which is achievable with ongoing and upcoming radio surveys such as ASKAP or SKA.

    ↳ astro-ph.COastro-ph.GAastro-ph.HEgr-qc+1PRL(2026)·15 citations
23. 23*

    Machine Learning-Assisted Unfolding for Neutrino Cross-section Measurements with the OmniFold Technique

    Roger G. Huang🇺🇸 · Andrew Cudd🇺🇸 · Masaki Kawaue🇯🇵 · Tatsuya Kikawa🇯🇵 · Benjamin Nachman🇺🇸 · Vinicius Mikuni🇺🇸 · Callum Wilkinson🇺🇸

    The choice of unfolding method for a cross-section measurement is tightly coupled to the model dependence of the efficiency correction and the overall impact of cross-section modeling uncertainties in the analysis. A key issue is the dimensionality used in unfolding, as the kinematics of all outgoing particles in an event typically affect the reconstruction performance in a neutrino detector. OmniFold is an unfolding method that iteratively reweights a simulated dataset, using machine learning to utilize arbitrarily high-dimensional information, that has previously been applied to proton-proton and proton-electron datasets. This paper demonstrates OmniFold's application to a neutrino cross-section measurement for the first time using a public T2K near detector simulated dataset, comparing its performance with traditional approaches using a mock data study.

    ↳ physics.data-anhep-exhep-phPRD(2025)·15 citations
24. 24*

    Kaon-meson coupling from SU(3) flavour symmetry and application to antikaon condensed dense matter in neutron star

    Athira S.🇮🇳 · Monika Sinha🇮🇳 · Vivek Baruah Thapa🇮🇳 · Vishal Parmar🇮🇳

    Observations of massive pulsars suggest that the central density of neutron stars can exceed several times the nuclear saturation density, creating a favourable environment for the appearance of exotic states, such as strange and non-strange baryons, meson condensates, and deconfined quark matter. The antikaon condensate is the most studied and plausible candidate among meson condensates. However, little is known about the exact interaction mechanisms between antikaons and mediator mesons. In this work, we investigate these interactions by, for the first time, employing SU(3) flavor symmetry to study antikaon condensation in dense matter. We determine hadron couplings in the mesonic sector using SU(3) flavour symmetry. Among the three key parameters we calculate ${\theta }_v$, the mixing angle between the octet meson ${\omega }_8$ and the singlet meson ${\varphi }_1$; the ratio of the octet to singlet couplings $z$; and leave the weight factor that balances the symmetric and antisymmetric couplings ${\alpha }_v$ as a free parameter to explore its impact on the system. Using this approach, we derive the couplings for antikaon interactions with both singlet and octet mesons in the nonet vector meson family and examine the corresponding implications for dense matter featuring antikaon condensation. Our findings reveal that the equation of state for dense matter becomes progressively stiffer with increasing values of ${\alpha }_v$, which delays the onset of antikaon condensation and increases the maximum achievable mass of neutron stars.

    ↳ nucl-thhep-phJCAP(2025)·2 citations
25. 25*

    Holographic hybrid stars with slow phase transitions

    M. Aleixo🇧🇷 · C. H. Lenzi🇧🇷 · M. Dutra🇧🇷 · O. Lourenço🇧🇷 · W. de Paula🇧🇷

    The $D_3$-$D_7$ holographic model is used to describe the core of the hybrid star, composed by quark matter, while its crust is modeled from a hadronic relativistic mean field (RMF) model capable of reproducing low-energy nuclear physics data as well as some astrophysical observations. The $D_3$-$D_7$ brane configuration and the RMF model lead to an equation of state that is used to solve the Tolman-Oppenheimer-Volkoff equations. For different model parameters, the mass-radius diagram is presented. The conditions for the dynamic stability of stellar configurations are discussed, considering the radial oscillation criterion for hybrid stars with slow phase transitions. Strikingly, it is shown that the models generate stable star configurations with a core of quarks. We compare our results with NICER observational data for the pulsars PSR J0030+0451 and PSR J0740+6620 and show that the compact stars generated from this method fall within the corresponding observational regions.

    ↳ nucl-thhep-phPRD(2025)·1 citation
26. 26*

    Decoherence effects in entangled fermion pairs at colliders

    Rafael Aoude🇬🇧 · Alan J. Barr🇬🇧 · Fabio Maltoni🇧🇪 · Leonardo Satrioni🇬🇧

    Recent measurements at the Large Hadron Collider have observed entanglement in the spins of $t\bar{t}$ pairs. The effects of radiation, which are expected to lead to quantum decoherence and a reduction of entanglement, are generally neglected in such measurements. In this work we calculate the effects of decoherence from various different types of radiation for a maximally entangled pair of fermions -- a bipartite system of qubits in a Bell state. We identify the Kraus operators describing the evolution of the open quantum system with the integrated Altarelli-Parisi splitting functions.

    ↳ quant-phhep-exhep-phPRD(2026)·24 citations

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