Mon·Nov 18, 2024Monday·November 18, 2024

1. 01*

   Thermo-Coupled Early Dark Energy

   Marc Kamionkowski🇺🇸 · Anubhav Mathur🇺🇸

   Early dark energy solutions to the Hubble tension introduce an additional scalar field which is frozen at early times but becomes dynamical around matter-radiation equality. In order to alleviate the tension, the scalar's share of the total energy density must rapidly shrink from $\sim 10\%$ at the onset of matter domination to $\ll 1\%$ by recombination. This typically requires a steep potential that is imposed $\text{ad hoc}$ rather than emerging from a concrete particle physics model. Here, we point out an alternative possibility: a homogeneous scalar field coupled quadratically to a cosmological background of light thermal relics (such as the Standard Model neutrino) will acquire an effective potential which can reproduce the dynamics necessary to alleviate the tension. We identify the relevant parameter space for this "thermo-coupled" scenario and study its unique phenomenology at the background level, including the back-reaction on the neutrino mass. Follow-up numerical work is necessary to determine the constraints placed on the model by early-time measurements.

   hep-phastro-ph.COPRD(2025)·11 citations
2. 02*

   Imprints of Early Universe Cosmology on Gravitational Waves

   James B. Dent🇺🇸 · Bhaskar Dutta🇺🇸 · Mudit Rai🇺🇸

   We explore the potential of gravitational waves (GWs) to probe the pre-BBN era of the early universe, focusing on the effects of energy injection. Specifically, we examine a hidden sector alongside the Standard Model that undergoes a strong first-order phase transition (FOPT), producing a GW signal. Once the phase transition has completed, energy injection initiates reheating in the hidden sector, which positions the hidden sector field so that additional phase transitions can occur. This can result in a total of three distinct phase transitions with a unique three-peak GW spectrum. Among these transitions, the first and third are of the standard type, while the intermediate second transition is inverted, moving from a broken to an unbroken phase. Using polynomial potentials as a framework, we derive analytical relations among the phase transition parameters and the resulting GW spectrum. Our results indicate that the second and third transitions generate GWs with higher amplitudes than the first, with a peak frequency ratio differing by up to an order of magnitude. This three-peak GW spectrum is detectable by upcoming facilities such as LISA, BBO, and UDECIGO. Notably, the phenomenon is robust across various potentials and model parameters, suggesting that hidden sector GWs provide a powerful tool for exploring new physics scenarios in the pre-BBN era.

   hep-phastro-ph.COgr-qcJHEP(2025)·11 citations
3. 03*

   Efficient Quantum Simulation of QCD Jets on the Light Front

   Wenyang Qian🇪🇸 · Meijian Li🇪🇸 · Carlos A. Salgado🇪🇸 · Michael Kreshchuk🇺🇸

   Quark and gluon jets provide one of the best ways to probe the matter produced in ultrarelativistic high-energy collisions, from cold nuclear matter to hot quark-gluon plasma. In this work, we propose a unified framework for efficient quantum simulation of many-body dynamics using the (3+1)-dimensional QCD Hamiltonian on the light front, particularly suited for studying the scattering of quark and gluon jets on nuclear matter in heavy-ion collisions. We describe scalable methods for mapping physical degrees of freedom onto qubits and for simulating in-medium jet evolution. We then validate our framework by implementing an algorithm that directly maps second-quantized Fock states onto qubits and uses Trotterized simulation for simulating time dynamics. Using a classical emulator, we investigate the evolution of quark and gluon jets with up to three particles in Fock states, extending prior studies. These calculations enable the study of key observables, including jet momentum broadening, particle production, and parton distribution functions.

   hep-phnucl-thquant-phPRD(2025)·23 citations
4. 04*

   The Neutrino Mass Bound from Leptogenesis Revisited

   Björn Garbrecht🇩🇪 · Edward Wang🇩🇪

   Recent years have seen a great improvement in the computation of $CP$-conserving and $CP$-violating equilibration rates for leptogenesis. These are relevant for the relativistic regime of the sterile Majorana fermions and the dynamics of the Standard Model particles acting as spectator processes. In order to probe the regime of large $(\mathcal{O}(10^2))$ washout parameters, we add $\Delta L=2$ washout processes, which we derive in the CTP-formalism. To demonstrate their significance, we apply state-of-the-art computational techniques to a simple yet well-motivated phenomenological scenario: unflavored leptogenesis in a hierarchical type-I seesaw model. We then perform a parameter scan of the final baryon asymmetry and find a constraint $m_{\text{lightest}}\lesssim 0.15\text{eV}$ on the absolute neutrino mass scale, which is slightly less stringent than previously reported bounds obtained without the aforementioned improvements. The relaxation of the bounds is mainly due to partially equilibrated spectator fields, which protect part of the asymmetry from washout and lead to larger final asymmetries. While this might seem like a minor correction, the actual dynamics of the fields is substantially altered by these effects. Even though we focused on a particularly simple scenario for leptogenesis, the methods employed here can and should be extended to other models, thus giving us a more accurate picture of the different leptogenesis scenarios.

   hep-phastro-ph.COhep-exJHEP(2025)·8 citations
5. 05*

   Radiative corrections to one- and two-meson tau decays for precise new physics tests

   Pablo Roig🇲🇽

   We review the radiative corrections to the $\tau \to P(P){\nu }_{\tau }[\gamma ]$ decays and their implications for several SM tests: lepton universality, CKM unitarity and non-standard interactions.

   hep-phPoS(2024)·0 citations
6. 06*

   Hadronic vacuum polarization contribution to the muon g-2 on Euclidean windows from tau data

   Pere Masjuan🇪🇸 · Alejandro Miranda🇪🇸 · Pablo Roig🇲🇽

   We computed for the first time the $\tau$ data-driven Euclidean windows for the hadronic vacuum polarization contribution to the muon g-2. We showed that $\tau$-based results agree with the available lattice window evaluations and with the full result. On the intermediate window, where all lattice evaluations are rather precise and agree, $\tau$-based results are compatible with them. This is particularly interesting, given that the disagreement of the $e^{+}{e}^{-}$ data-driven result with the lattice values in this window is the main cause for their discrepancy, affecting the interpretation of the $a_{\mu }$ measurement in terms of possible new physics.

   hep-phPoS(2025)·2 citations
7. 07*

   Quantum similarity learning for anomaly detection

   A. Hammad🇯🇵 · Mihoko M. Nojiri🇯🇵 · Masahito Yamazaki🇯🇵

   Anomaly detection is a vital technique for exploring signatures of new physics Beyond the Standard Model (BSM) at the Large Hadron Collider (LHC). The vast number of collisions generated by the LHC demands sophisticated deep learning techniques. Similarity learning, a self-supervised machine learning, detects anomalous signals by estimating their similarity to background events. In this paper, we explore the potential of quantum computers for anomaly detection through similarity learning, leveraging the power of quantum computing to enhance the known similarity learning method. In the realm of noisy intermediate-scale quantum (NISQ) devices, we employ a hybrid classical-quantum network to search for heavy scalar resonances in the di-Higgs production channel. In the absence of quantum noise, the hybrid network demonstrates improvement over the known similarity learning method. Moreover, we employ a clustering algorithm to reduce measurement noise from limited shot counts, resulting in $9\%$ improvement in the hybrid network performance. Our analysis highlights the applicability of quantum algorithms for LHC data analysis, where improvements are anticipated with the advent of fault-tolerant quantum computers.

   hep-phhep-exquant-phJHEP(2025)·8 citations
8. 08*

   Effect of Coriolis Force on Diffusion of D Meson

   Ashutosh Dwibedi🇮🇳 · Nandita Padhan🇮🇳 · Dani Rose J Marattukalam🇮🇳 · Arghya Chatterjee🇮🇳 · Sudipan De🇮🇳 · Sabyasachi Ghosh🇮🇳

   We have attempted to calculate and estimate the spatial diffusion coefficients of D meson through rotating hadron resonance gas, which can be produced in the late stage of peripheral heavy ion collisions. Employing the framework of kinetic theory in relaxation time approximation, and using Einstein's diffusion relation, one can express the spatial diffusion coefficients of D meson as a ratio of its conductivity to its susceptibility. Here, we have tuned D meson relaxation time from the knowledge of earlier works on its spatial diffusion estimations, and then we have extended the framework for the finite rotation picture of hadronic matter, where only the effect of Coriolis force is considered. Our study also revealed the anisotropic nature of diffusion in the presence of rotation with future possibilities of phenomenological signature.

   hep-phhep-exnucl-thJ.Phys.G(2025)·5 citations
9. 09*

   Photon polarization tensor at finite temperature and density in a magnetic field

   Kenji Fukushima🇯🇵 · Yoshimasa Hidaka🇯🇵 · Tomoya Uji🇯🇵

   We present analytical and numerical calculations for the photon polarization tensor at finite temperature and density in a constant magnetic field. We first discuss the tensor decomposition in the presence of the magnetic field, which breaks rotational symmetry. Then, we analytically perform all the momentum integrations and numerically take the Landau level sum. We confirm that the imaginary part of the photon polarization tensor correctly reproduces the known result from the independent calculation. We utilize the Kramers-Kronig relation to estimate the real part numerically as a function of the momenta, the chemical potential, and the finite temperature. As an application, we consider the real photon limit and estimate the photon decay rate and the Stokes parameter in the hot and dense medium. We specifically quantify the difference between the X-mode and the O-mode with the polarization orthogonal and parallel to the magnetic field. As long as the magnetic field is weak, the decay rate of the X-mode photon is larger than that of the O-mode photon, while the O-mode becomes dominant due to the Landau level suppression of the X-mode at a strong magnetic field. We also find that the eigenmodes of the propagating photon change their polarization state with increasing density.

   hep-phnucl-thJHEP(2025)·4 citations
10. 10*

    Suppression of diffraction in DIS on nuclei and dynamical mechanism of leading twist nuclear shadowing

    V. Guzey (Jyvaskyla U. and Helsinki U.)🇫🇮

    Using the leading twist approach (LTA) to nuclear shadowing (NS), we calculate the ratio of the diffractive-to-total DIS cross sections $R_{diff/tot}$ for a heavy nucleus and proton and confirm that $R_{diff/tot}\approx 0.5-1$ in contrast with $R_{diff/tot}\approx 1.5-2$ in the dipole model. We show that the magnitude of $R_{diff/tot}$ is controlled by an effective dipole cross section so that $R_{diff/tot}\to 1$ in the black disk limit. We also argue that strong leading twist NS as well as the dilute nuclear density deplete nuclear enhancement of the saturation scale leading to $Q_{sA}^2(b=0)/Q_{sp}^2(b=0)\sim 1$.

    hep-phActa Phys.Polon.Supp.(2025)·0 citations
11. 11*

    Four loop Green's functions involving the $n$ $=$ $2$ moment of the Wilson operator

    J.A. Gracey🇬🇧

    We evaluate the Green's function for the insertion of the second moment of the twist-$2$ flavour nonsinglet Wilson operator in a quark $2$-point function in all three different single scale external momentum configurations at four loops in the MSbar scheme and the chiral limit. One configuration is where the operator is inserted at zero momentum while the other two are where a non-zero momentum flows out through the operator itself with one external quark momentum nullified. In the latter two configurations mixing of the operator with a total derivative twist-$2$ operator is included for renormalization group consistency. In addition we compute the correlation functions of both gauge invariant operators to four loops in the same scheme.

    hep-phhep-latEPJC(2025)·0 citations
12. 12*

    Constraints on large scalar multiplets added to the Standard Model

    Darius Jurčiukonis🇱🇹 · Luís Lavoura🇵🇹

    We study the extension of the Standard Model (SM) by introducing a scalar multiplet with arbitrary isospin $J$ and hypercharge $Y$. We explicitly consider various possible values of the weak isospin $J$, up to and including $J=7/2$. The mass differences among the components of the multiplet originate from its coupling to the Higgs doublet of the SM, as present in the scalar potential (SP). We derive exact bounded-from-below (BFB) and unitarity (UNI) conditions for this model, even when the SP includes the most general quartic terms involving the multiplet components. We find that the upper bound on the mass differences depends not only on the UNI conditions but also on the BFB ones, thus imposing constraints on the mass differences. We compare these constraints to those derived from the oblique parameters (OPs) and from solutions of the renormalization-group equations (RGEs).

    hep-ph0 citations
13. 13*

    Directional Direct Detection of MeV Scale Boosted Dark Matter in Two Component Dark Matter Scenario via Dark Photon Interaction

    Keiko I. Nagao🇯🇵 · Tatsuhiro Naka🇯🇵 · Takaaki Nomura🇨🇳

    This study explores a two-component dark matter model in which one component, heavier dark matter, annihilates into a lighter dark matter. The lighter dark matter is expected to generate detectable signals in detectors due to its enhanced momentum, enabling direct detection even for MeV-scale dark matter. We investigate the effectiveness of directional direct detections, especially the nuclear emulsion detector NEWSdm, in verifying these boosted dark matter particles through nuclear recoil. In particular, we focus on light nuclei, such as protons and carbon, as suitable targets for this detection method due to their high sensitivity to MeV-scale dark matter. By modeling the interactions mediated by a dark photon in a hidden U(1)${}_D$ gauge symmetry framework, we calculate the expected dark matter flux and scattering rates for various detector configurations. Our results show that nuclear emulsions have the potential to yield distinct, direction-sensitive dark matter signals from the Galactic center, providing a new way to probe low-mass dark matter parameter spaces that evade conventional detection methods.

    hep-phastro-ph.COhep-exJCAP(2025)·7 citations
14. 14*

    On the dark matter origin of an LDMX signal

    Riccardo Catena🇸🇪 · Taylor R. Gray🇸🇪 · Andreas Lund🇸🇪

    Fixed target experiments where beam electrons are focused upon a thin target have shown great potential for probing new physics, including the sub-GeV dark matter (DM) paradigm. However, a signal in future experiments such as the light dark matter experiment (LDMX) would require an independent validation to assert its DM origin. To this end, we propose to combine LDMX and next generation DM direct detection (DD) data in a four-step analysis strategy, which we here illustrate with Monte Carlo simulations. In the first step, the hypothetical LDMX signal (i.e. an excess in the final state electron energy and transverse momentum distributions) is $\text{recorded}$. In the second step, a DM DD experiment operates with increasing exposure to test the DM origin of the LDMX signal. Here, LDMX and DD data are simulated. In the third step, a posterior probability density function (pdf) for the DM model parameters is extracted from the DD data, and used to $\text{predict}$ the electron recoil energy and transverse momentum distributions at LDMX. In the last step, $\text{predicted}$ and $\text{recorded}$ electron recoil energy and transverse momentum distributions are compared in a chi-square test. We present the results of this comparison in terms of a threshold exposure that a DD experiment has to operate with to assert whether $\text{predicted}$ and $\text{recorded}$ distributions $\text{can}$ be statistically dependent. We find that this threshold exposure grows with the DM particle mass, $m_{\chi }$. It varies from 0.012 kg-year for a DM mass of $m_{\chi }=4$ MeV to 1 kg-year for $m_{\chi }=25$ MeV, which is or will soon be within reach.

    hep-phastro-ph.COhep-exJCAP(2025)·1 citation
15. 15*

    Compatibility between $e^{+}{e}^{-}$ and $\tau$ decay data in the di-pion channel and implications for $a_{\mu }^{\mathrm{SM}}$ and CVC tests

    Alejandro Miranda🇪🇸

    We have revisited the isospin-breaking corrections relating $\sigma (e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-})$ and $\Gamma ({\tau }^{-}\to {\pi }^{-}{\pi }^0{\nu }_{\tau })$. We confirm that the associated uncertainty is under control, so that tau data can also be used to predict accurately the leading hadronic contribution to the muon anomalous magnetic moment and precision conserved vector current tests can be carried out.

    hep-phhep-exhep-lat3 citations
16. 16*

    Bridging correlation and spectroscopy measurements to access the hadron interaction behind molecular states: the case of the $\Xi$(1620) and $\Xi$(1690) in the $K^{-}\Lambda$ system

    A. Feijoo🇩🇪 · V. Mantovani Sarti🇩🇪 · J. Nieves🇪🇸 · A . Ramos🇪🇸 · I Vidaña🇮🇹

    We study the compatibility between the $K^{-}\Lambda$ correlation function, recently measured by the ALICE collaboration, and the LHCb $K^{-}\Lambda$ invariant mass distribution obtained in the ${\Xi }_b^{-}\to J/\psi \Lambda K^{-}$ decay. The $K^{-}\Lambda$ invariant mass distribution associated with the ${\Xi }_b^{-}$ decay has been calculated within the framework of Unitary Effective Field Theories using two models, one of them constrained by the $K^{-}\Lambda$ correlation function. We consider two degenerate pentaquark $P_{cs}$ states in the $J/\psi \Lambda$ scattering amplitude which allows us to investigate their impact on both the $K^{-}\Lambda$ and $J/\psi \Lambda$ mass distributions assuming different spin-parity quantum numbers and multiplicity. Without any fitting procedure, the $K^{-}\Lambda$ model is able to better reproduce the experimental $K^{-}\Lambda$ mass spectrum in the energy region above $1680$ MeV as compared to previous unitarized scattering amplitudes constrained to a large amount of experimental data in the neutral $S=-1$ meson-baryon sector. We observe a tension between our model and the LHCb $K^{-}\Lambda$ distribution in the region close to the threshold, largely dominated by the presence of the still poorly known $\Xi$(1620) state. We discuss in detail the different production mechanisms probed via femtoscopy and spectroscopy that could provide valid explanations for such disagreement, indicating the necessity to employ future correlation data in other $S=-2$ channels such as $\pi \Xi$ and $\bar{K}\Sigma$.

    hep-phPRD(2025)·11 citations
17. 17*

    Two-loop corrections in power spectrum in models of inflation with PBHs formation

    Hassan Firouzjahi🇮🇷

    We calculate the two-loop corrections in primordial power spectrum in models of single field inflation incorporating an intermediate USR phase employed for PBHs formation. Among the total eleven one-particle irreducible Feynman diagrams, we calculate the corrections from the "double scoop" two-loop diagram involving two vertices of quartic Hamiltonians. We demonstrate that the fractional two-loop correction in power spectrum scales like the square of the fractional one-loop correction. We confirm our previous findings that the loop corrections become arbitrarily large in the setup where the transition from the intermediate USR to the final slow-roll phase is very sharp. This suggests that in order for the analysis to be under perturbative control against loop corrections, one requires a mild transition with a long enough relaxation period towards the final attractor phase.

    hep-phastro-ph.COgr-qchep-thUniverse(2024)·12 citations
18. 18*

    Universal non-equilibrium scaling of cumulants across a critical point

    Leon J. Sieke🇩🇪 · Mattis Harhoff🇩🇪 · Sören Schlichting🇩🇪 · Lorenz von Smekal🇩🇪

    We study the critical dynamics of a scalar field theory with $Z_2$ symmetry in the dynamic universality class of Model A in two and three spatial dimensions with classical-statistical lattice simulations. In particular, we measure the non-equilibrium behavior of the system under a quench protocol in which the symmetry-breaking external field is changed at a constant rate through the critical point. Using the well-established Kibble-Zurek scaling theory we compute non-equilibrium scaling functions of cumulants of the order parameter up to fourth order. Together with the static critical exponents and the dynamic critical exponent, these fully describe the universal non-equilibrium evolution of the system near the critical point. We further extend the analysis to include finite-size effects and observe good collapse of our data onto two-dimensional universal non-equilibrium and finite-size scaling functions.

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

    ${\mu }^{-}\to e^{-}\gamma$ in a muonic atom as a probe for effective lepton flavor violating operators involving photon fields

    Yuichi Uesaka · Masato Yamanaka🇯🇵 · Yoshitaka Kuno🇯🇵

    We propose the ${\mu }^{-}\to e^{-}\gamma$ process in a muonic atom as a novel means to investigate charged lepton flavor violation (CLFV). We demonstrate its sensitivity in probing effective CLFV operators associated with both single and double photon fields. In comparison to ${\mu }^{+}\to e^{+}\gamma$ using free positive muon decays at rest, the emitted electron and photon in ${\mu }^{-}\to e^{-}\gamma$ exhibit non-monochromatic spectra, presenting non-trivial case. We derive the decay rate formula and demonstrate that the potential rate of the process is significant enough to motivate exploration in future muon CLFV experiments.

    hep-phPRD(2025)·7 citations
20. 20*

    Dynamic scaling and quenching for heavy quark in the linear expanding medium

    Boris Blok (Technion)🇩🇪 · Chang Wu (Technion)🇩🇪

    We show that scaling is a good approximation for the energy loss of the heavy quark propagating through linear expanding quark-gluon plasma (QGP), the effective quenching parameter does not depend on quark mass.

    hep-phnucl-exnucl-thEPJC(2026)·1 citation
21. 21*

    Scalar and tensor meson dominance and gravitational form factors of the pion

    Enrique Ruiz Arriola🇪🇸 · Wojciech Broniowski🇵🇱

    We analyze the recent MIT lattice data for the gravitational form factors (GFFs) of the pion which extend up to $Q^2=2{\mathrm{GeV}}^2$ for $m_{\pi }=170$~MeV~\cite{Hackett:2023nkr}. We show that simple monopole fits comply with the old idea of meson dominance. We use Chiral Perturbation theory ($\chi$PT) to next-to-leading order (NLO) to transform the MIT data to the physical world with $m_{\pi }=140$MeV and find that the spin-0 GFF is effectively saturated with the $f_0(600)$ and the spin-2 with the $f_2(1270)$, with monopole masses $m_{\sigma }=630(60)$~MeV and $m_{f_2}=1270(40)$~MeV. We determine in passing the chiral low energy constants (LECs) from the MIT lattice data alone \[ 10^3 \cdot L_{11} (m_\rho^2)=1.06(15) \, , \qquad 10^3 \cdot L_{12} (m_\rho^2)= -2.2(1) \, , \qquad 10^3 \cdot L_{13} (m_\rho^2) = -0.7(1.1). \] which agree in sign and order of magnitude % to be compared with the original estimates by Donoghue and Leutwyler. The corresponding D-term (druck) has the value $D(0)=-0.95(3)$. We also analyze the sum rules based on perturbative QCD (pQCD) that imply that the corresponding spectral functions are not positive definite. We show that these sum rules are strongly violated in a variety of $\pi \pi -K\bar{K}$ coupled channel Omnès-Muskhelishvili calculations. This is not mended by the inclusion of the pQCD tail, suggesting the need for an extra negative spectral strength. Using a simple model implementing all sum rules, we find the expected onset of pQCD at very high momenta.

    hep-phhep-latPoS(2025)·6 citations
22. 22*

    The role of Padé and D-Log Padé approximants in the context of the MUonE Experiment

    Camilo Rojas P.🇪🇸 · Diogo Boito🇧🇷 · Cristiane Y. London🇧🇷 · Pere Masjuan🇪🇸

    In the context of the anomalous magnetic moment of the muon, the hadronic contribution plays a crucial role, especially given its large contribution to the final error. Currently, lattice QCD simulations are in disagreement with dispersive calculations based on $e^{+}{e}^{-}$ hadronic cross sections. The new MUonE experiment intends to shed light on this situation extracting the hadronic contribution to the running of the electromagnetic coupling in the space-like region, $\Delta {\alpha }_{\mathrm{had}}(t)$, from elastic $e\mu$ scattering. Still, due to the limited kinematic range that can be covered by the experiment, a powerful method must be devised to accurately extract the desired hadronic contribution from a new experiment of this type. In this work, we show how Padé and D-Log Padé approximants profiting from the analyticity of the correlator governing the hadronic contribution can be a powerful tool in reaching the required precision.

    hep-phhep-thPoS(2025)·0 citations
23. 23*

    Superconnections in AdS/QCD and the hadronic light-by-light contribution to the muon $g-2$

    Josef Leutgeb🇦🇹 · Jonas Mager🇦🇹 · Anton Rebhan🇦🇹

    In this paper, we consider hard-wall AdS/QCD models extended by a string-theory inspired Chern-Simons action in terms of a superconnection involving a bi-fundamental scalar field which corresponds to the open-string tachyon of brane-antibrane configurations and which is naturally identified with the holographic dual of the quark condensate in chiral symmetry breaking. This realizes both the axial and chiral anomalies of QCD with a Witten-Veneziano mechanism for the ${\eta }^{\prime }$ mass in addition to current quark masses, but somewhat differently than in the Katz-Schwartz AdS/QCD model used previously by us to evaluate pseudoscalar and axial vector transition form factors and their contribution to the HLBL piece of the muon $g-2$. Compared to the Katz-Schwartz model, we obtain a significantly more realistic description of axial-vector mesons with regard to $f_1$-$f_1^{\prime }$ mixing and equivalent photon rates. Moreover, predictions of the $f_1\to e^{+}{e}^{-}$ branching ratios are found to be in line with a recent phenomenological study. However, pseudoscalar transition form factors compare less well with experiment; in particular the ${\pi }^0$ transition form factor turns out to be overestimated at moderate non-zero virtuality. For the combined HLBL contribution to the muon $g-2$ from the towers of axial vector mesons and excited pseudoscalars we obtain, however, a result very close to that of the Katz-Schwartz model.

    hep-phhep-thPRD(2025)·19 citations
24. 24*

    Detecting the QCD axion via the ferroaxionic force with piezoelectric materials

    Asimina Arvanitaki🇨🇦 · Jonathan Engel🇺🇸 · Andrew A. Geraci🇺🇸 · Alexander Hepburn🇺🇸 · Amalia Madden🇺🇸 · Ken Van Tilburg🇺🇸

    We show that piezoelectric materials can be used to source virtual QCD axions, generating a new axion-mediated force. Spontaneous parity violation within the piezoelectric crystal combined with time-reversal violation from aligned spins provide the necessary symmetry breaking to produce an effective in-medium scalar coupling of the axion to nucleons up to 7 orders of magnitude larger than that in vacuum. We propose a detection scheme based on nuclear spin precession caused by the axion's pseudoscalar coupling to nuclear spins. This signal is resonantly enhanced when the distance between the source crystal and the spin sample is modulated at the spin precession frequency. Using this effect, future experimental setups can be sensitive to the QCD axion in the unexplored mass range from $10^{-5}\mathrm{eV}$ to $10^{-2}\mathrm{eV}$.

    hep-phhep-exnucl-thPRL(2026)·7 citations
25. 25*

    Radiation Exposure from the Dark

    Florian Niedermann🇸🇪 · Martin S. Sloth🇩🇰

    We explore the possibility that exotic forms of dark matter could expose humans on Earth or on prolonged space travel to a significant radiation dose. The radiation exposure from dark matter interacting with nuclei in the human body is generally assumed to be negligible compared to other sources of background radiation. However, as we discuss here, current data allow for dark matter models where this is not necessarily true. In particular, if dark matter is heavier and more strongly interacting than weakly interacting massive particle dark matter, it could act as ionizing radiation and deposit a significant amount of radiation energy in all or part of the human population, similar to or even exceeding the known radiation exposure from other background sources. Conversely, the non-observation of such an exposure can be used to constrain this type of heavier and more strongly interacting dark matter. We first consider the case where dark matter scatters elastically and identify the relevant parameter space in a model-independent way. We also discuss how previous bounds from cosmological probes, as well as atmospheric and space-based detectors, might be avoided, and how a re-analysis of existing radiation data, along with a simple experiment monitoring ionizing radiation in space with a lower detection threshold, could help constrain part of this parameter space. We finally propose a hypothetical dark matter candidate that scatters inelastically and argue that, in principle, one per mille of the Earth's population could attain a significant radiation dose from such a dark matter exposure in their lifetime.

    hep-phastro-ph.COphysics.space-phJCAP(2025)·2 citations
26. 26*

    Hadronic decay of vector charmonium from the lattice

    Benoît Blossier🇫🇷 · Jochen Heitger🇩🇪 · Jan Neuendorf🇫🇷 · Teseo San José🇫🇷

    Estimating decay parameters in lattice simulations is a computationally demanding problem, requiring several volumes and momenta. We explore an alternative approach, where the transition amplitude can be extracted from the spectral decomposition of particular ratios built from correlation functions. This so-called ratio method has the advantage of not needing various irreducible representations or volumes, and it allows us to predict the decay width $\Gamma$ and the energy shift $ϵ$ of the spectrum directly. In this work, we apply this method to study the hadronic decay $\psi (3770)\to \bar{D}D$ on two CLS $N_{\text{f}}=2$ ensembles. This approach requires close to on-shell kinematics to work, and we employ twisted boundary conditions to precisely tune the on-shell point. Although our study is yet to approach the continuum limit, we find a value of $\Gamma$ fully compatible to the physical result, and $ϵ$ informs us by how much our spectrum would shift in a fully dynamical simulation. Besides lattice calculations, many analytical tools have been proposed to understand decay processes. A relatively simple, early example is the ${}^3{P}_0$ quark model, which provides a physical insight of the decay process.

    ↳ hep-lathep-phJHEP(2025)·3 citations
27. 27*

    Aspects of the chiral crossover transition in (2+1)-flavor QCD with Möbius domain-wall fermions

    Rajiv V. Gavai🇮🇳 · Mischa E. Jaensch🇩🇪 · Olaf Kaczmarek🇩🇪 · Frithjof Karsch🇩🇪 · Mugdha Sarkar🇹🇼 · Ravi Shanker🇮🇳 · Sayantan Sharma🇮🇳 · Sipaz Sharma🇩🇪 · Tristan Ueding🇩🇪

    The non-singlet part of the chiral symmetry in QCD with two light flavors is known to be restored through a crossover transition at a pseudo-critical temperature. However, the temperature dependence of the singlet part of the chiral symmetry and whether it is effectively restored at the same temperature is not well understood. Using (2+1)-flavor QCD configurations generated using the Möbius domain-wall discretization on an $N_{\tau }=8$ lattice, we construct suitable observables where the singlet and non-singlet chiral symmetries are disentangled in order to study their temperature dependence across the crossover transition. From the peak of the disconnected part of the chiral susceptibility, we obtain a pseudo-critical temperature $T_{pc}=158.7{}_{-2.3}^{+2.6}$ MeV where the non-singlet part of the chiral symmetry is effectively restored. From a calculation of the topological susceptibility and its temperature dependence we find that the singlet $U_A(1)$ part of the chiral symmetry is not effectively restored at $T<186$ MeV.

    ↳ hep-lathep-phPRD(2025)·25 citations
28. 28*

    Ultra High Energy Cosmic Rays versus Models of High Energy Hadronic Interactions

    Blaž Bortolato🇸🇮 · Jernej F. Kamenik🇸🇮 · Michele Tammaro🇮🇹

    We evaluate the consistency of hadronic interaction models in the CORSIKA simulation package with publicly available fluorescence telescope data from the Pierre Auger Observatory. By comparing the first few central moments of the extended air shower depth maximum distributions, as extracted from measured events, to those predicted by the best-fit inferred compositions, we derive a statistical measure of the consistency of a given hadronic model with data. To mitigate possible systematic biases, we include all primaries up to iron, compensate for the differences between the measured and simulated energy spectra of cosmic rays and account for other known systematic effects. Additionally, we study the effects of including higher central moments in the fit and project our results to larger statistics.

    ↳ astro-ph.HEhep-phEPJC(2025)·0 citations

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