Thu·Jun 27, 2024Thursday·June 27, 2024

1. 01*

   Discrete dark matter with light Dirac neutrinos

   Debasish Borah🇮🇳 · Pritam Das🇮🇳 · Biswajit Karmakar🇵🇱 · Satyabrata Mahapatra🇰🇷

   We propose a new realisation of light Dirac neutrino mass and dark matter (DM) within the framework of a non-Abelian discrete flavour symmetry based on $A_4$ group. In addition to $A_4$, we also consider a $Z_2$ and an unbroken global lepton number symmetry $U(1{)}_L$ to keep unwanted terms away while guaranteeing the Dirac nature of light neutrinos. The field content, their transformations and flavon vacuum alignments are chosen in such a way that the type-I Dirac seesaw generates only one light Dirac neutrino mass while the other two masses arise from scotogenic contributions at one-loop. This leads to the Dirac scoto-seesaw framework, a generalisation of the widely studied scoto-seesaw model to Dirac neutrinos. The symmetry breaking of $A_4$ leaves a remnant ${\mathcal{Z}}_2$ symmetry responsible for stabilising DM. Dirac nature of light neutrinos introduces additional relativistic degrees of freedom $\Delta N_{\mathrm{eff}}$ within reach of cosmic microwave background experiments.

   hep-phastro-ph.COPRD(2025)·22 citations
2. 02*

   Matching the Weak Mixing Angle at Low Energies

   Hubert Spiesberger🇩🇪 · Stephan Wezorke

   The running weak mixing angle is used as a convenient tool to keep control of dominating logarithmic corrections in the Standard Model of the electroweak interactions connecting measurements at largely differing energy scales. To relate the solutions of the renormalization group equation for the weak mixing angle above and below particle thresholds one needs matching conditions. We suggest to define the matching at the W-boson threshold by comparing the full Standard Model with a low-energy effective theory where the weak neutral current, in particular for parity-violating fermion scattering, is described by 4-fermion operators and calculate the corresponding matching relation.

   hep-ph2 citations
3. 03*

   Time-kernel for lattice determinations of NLO hadronic vacuum polarization contributions to the muon $g$-$2$

   Elisa Balzani🇮🇹 · Stefano Laporta🇮🇹 · Massimo Passera🇮🇹

   We study the time-momentum representation of the kernel needed to compute hadronic vacuum polarization contributions to the muon $g$-$2$ in the space-like region at next-to-leading order. For small values of the time, we present analytical series expansions; for large values of the time, we present numerical series expansions which overcome the problems showed by naïve asymptotic expansions. These results are to be employed in lattice QCD determinations of hadronic vacuum polarization contributions to the muon $g$-$2$ at next-to-leading order.

   hep-phhep-latPLB(2024)·5 citations
4. 04*

   Precise determination of the bottom-quark on-shell mass using its four-loop relation to the $\overline{\mathrm{MS}}$-scheme running mass

   Shun-Yue Ma🇨🇳 · Xu-Dong Huang🇨🇳 · Xu-Chang Zheng🇨🇳 · Xing-Gang Wu🇨🇳

   In this paper, we explore the properties of the bottom-quark on-shell mass ($M_b$) by using its relation to the $\overline{\mathrm{MS}}$ mass (${\overline{m}}_b$). At present, this $\overline{\mathrm{MS}}$-on-shell relation has been known up to four-loop QCD corrections, which however still has a $\sim 2\%$ scale uncertainty by taking the renormalization scale as ${\overline{m}}_b({\overline{m}}_b)$ and varying it within the usual range of $[{\overline{m}}_b({\overline{m}}_b)/2,2{\overline{m}}_b({\overline{m}}_b)]$. The principle of maximum conformality (PMC) has been adopted to achieve a more precise $\overline{\mathrm{MS}}$-on-shell relation by eliminating such scale uncertainty. As a step forward, we also estimate the magnitude of the uncalculated higher-order terms by using the Padé approximation approach. Numerically, by using the $\overline{\mathrm{MS}}$ mass ${\overline{m}}_b({\overline{m}}_b)=4.183\pm 0.007$ GeV as an input, our predicted value for the bottom-quark on-shell mass becomes $M_b\simeq 5.372_{-0.075}^{+0.091}$ GeV, where the uncertainty is the squared average of the ones caused by $\Delta {\alpha }_s(M_Z)$, $\Delta {\overline{m}}_b({\overline{m}}_b)$, and the estimated magnitude of the higher-order terms.

   hep-phChin.Phys.Lett.(2024)·6 citations
5. 05*

   Complex scalar dark matter in a new gauged U(1) symmetry with kinetic and direct mixings

   Yu-Hang Su🇨🇳 · Chengfeng Cai🇨🇳 · Yu-Pan Zeng🇨🇳 · Hong-Hao Zhang🇨🇳

   We propose a scalar dark matter model featuring a hidden gauge symmetry, denoted as U(1)_X, with two complex scalars, Phi and S. In this framework, Phi spontaneously breaks the U(1)_X gauge symmetry, while S serves as a viable dark matter candidate. Particularly, the kinetic and direct mixings between the U(1)_X and U(1)_Y gauge groups provide a portal between dark matter and the Standard Model particles. These mixings offer a plausible explanation for the W boson mass anomaly observed by the CDF Collaboration. We study the comprehensive phenomenological constraints of this model from colliders and dark matter detection experiments, including Z' searches at the LHC, the 125 GeV Higgs boson measurements, the relic density of dark matter and the indirect detection of dark matter annihilation. By randomly scanning the parameter space, we find that the regions where m_(Z') > 4750 GeV and m_(Z') < 4750 GeV for g_x close to 1 remain viable and can be tested by future experiments.

   hep-phastro-ph.COhep-exPRD(2024)·3 citations
6. 06*

   Transition magnetic moment of Majorana neutrinos in the triplets next-to-minimal MSSM

   Zhao-Yang Zhang🇨🇳 · Jin-Lei Yang🇨🇳 · Hai-Bin Zhang🇨🇳 · Tai-Fu Feng🇨🇳

   The TNMSSM is an attractive extension of the Standard Model. It combines the advantages of the NMSSM and the TMSSM to give three tiny Majorana neutrinos masses via a type I+II seesaw mechanism. With the on-shell renormalization scheme, we consider the neutrino masses up to one loop approximation. Applying the effective Lagrangian method, we study the transition magnetic moments of Majorana neutrinos and consider the normal hierarchy (NH) and inverse hierarchy (IH) neutrino mass spectra within the constraints of experimental data on neutrino oscillations. The solar neutrino transition magnetic moment is further deduced, and compared with the XENONnT experiment limit.

   hep-phPRD(2024)·8 citations
7. 07*

   Non-Planar Two-Loop Amplitudes for Five-Parton Scattering

   Giuseppe De Laurentis🇬🇧

   We review the current status of high-multiplicity double-virtual QCD corrections to processes relevant for LHC phenomenology. In particular, we discuss the recent full-color calculation of the five-parton process, whose two-loop amplitudes are required to obtain next-to-next-to-leading order predictions for three-jet production at the LHC. We address various aspects of the computation, including color decomposition, renormalization, partial amplitudes, color identities and the construction of the finite remainder. We review the method of numerical unitarity, which is used to generate finite-field samples of the amplitude. We then focus on the analytic reconstruction of the coefficient functions from these numerical samples via Ansatz techniques. A novel algorithm, based on the correlation of codimension-one residues, helps manage the complexity of the calculation. Little-group rescalings of the gluon amplitude, inspired by supersymmetry Ward identities, facilitate the computation of the quark amplitudes. We conclude with an outlook towards upcoming computations with an increased number of scales, leading to larger Ansätze and more complicated alphabets.

   hep-phPoS(2024)·3 citations
8. 08*

   Theories of flavour from the Planck scale to the electroweak scale

   Mario Fernández Navarro🇬🇧

   The flavour puzzle remains as one of the most intriguing enigmas of particle physics. In this thesis, we propose and study theories of flavour which generically hint to a multi-scale origin of flavour. First we explore the idea of fermiophobic models and messenger dominance, where the chiral fermions of the Standard Model are uncharged under (part of) an extended gauge symmetry, which also forbids Yukawa couplings for chiral fermions. These are generated effectively due to the presence of hierarchically heavy messengers, including vector-like fermions and/or heavy Higgs doublets. Simultaneously, this mechanism generates effective couplings of chiral fermions to the gauge bosons of the extended symmetry, leading to a predictive phenomenology connected to the origin of flavour hierarchies. We present two models of this kind, based on gauge $U(1)$ and twin Pati-Salam symmetries, that have implications for low energy flavour anomalies. Secondly, we study the framework of flavour deconstruction, where the Standard Model emerges from a non-universal gauge theory that contains a separate gauge factor for each fermion family. We argue that one of the most simple ways to achieve this is by assigning a separate gauge hypercharge to each fermion family, denoted as the "tri-hypercharge" theory. If the SM Higgs only carries third family hypercharge, then only the third family is massive at renormalisable level, and light families get their mass from higher dimensional operators. Finally, we propose a gauge unified origin for gauge non-universal frameworks such as the aforementioned tri-hypercharge theory. The model assigns a separate $SU(5)$ group to each fermion family. However, assuming that the three $SU(5)$ groups are related by a cyclic permutation symmetry ${\mathbb{Z}}_3$, then the model is described by a single gauge coupling in the ultraviolet, despite $SU(5{)}^3$ being a non-simple group.

   hep-phhep-th1 citation
9. 09*

   Relativistic theory of the viscosity of fluids across the entire energy spectrum

   Alessio Zaccone🇮🇹

   The shear viscosity is a fundamental transport property of matter. Here we derive a general theory of the viscosity of gases based on the relativistic Langevin equation (deduced from a relativistic Lagrangian) and nonaffine linear response theory. The proposed relativistic theory is able to recover the viscosity of non-relativistic classical gases, with all its key dependencies on mass, temperature, particle diameter and Boltzmann constant, in the limit of Lorentz factor $\gamma =1$. It also unveils the relativistic enhancement mechanism of viscosity. In the limit of ultrarelativistic fluids, the theory provides a new analytical formula which reproduces the cubic increase of viscosity with temperature in agreement with various estimates for hot dense matter and the QGP-type fluid.

   hep-phcond-mat.stat-mechhep-thphysics.class-ph+1PRE(2024)·2 citations
10. 10*

    Universal Anomaly Detection at the LHC: Transforming Optimal Classifiers and the DDD Method

    Sascha Caron🇳🇱 · José Enrique García Navarro🇪🇸 · María Moreno Llácer🇪🇸 · Polina Moskvitina🇳🇱 · Mats Rovers🇳🇱 · Adrián Rubio Jímenez🇪🇸 · Roberto Ruiz de Austri🇪🇸 · Zhongyi Zhang🇳🇱

    In this work, we present a novel approach to transform supervised classifiers into effective unsupervised anomaly detectors. The method we have developed, termed Discriminatory Detection of Distortions (DDD), enhances anomaly detection by training a discriminator model on both original and artificially modified datasets. We conducted a comprehensive evaluation of our models on the Dark Machines Anomaly Score Challenge channels and a search for 4-top quark events, demonstrating the effectiveness of our approach across various final states and beyond the Standard Model scenarios. We compare the performance of the DDD method with the Deep Robust One-Class Classification method (DROCC), which incorporates signals in the training process, and the Deep Support Vector Data Description (DeepSVDD) method, a well-established and well-performing method for anomaly detection. Results show that the effectiveness of each model varies by signal and channel, with DDD proving to be a very effective anomaly detector. We recommend the combined use of DeepSVDD and DDD for purely unsupervised applications, with the addition of flow models for improved performance when resources allow. Findings suggest that network architectures that excel in supervised contexts, such as the particle transformer with standard model interactions, also perform well as unsupervised anomaly detectors. We also show that with these methods, it is likely possible to recognize 4-top quark production as an anomaly without prior knowledge of the process. We argue that the Large Hadron Collider community can transform supervised classifiers into anomaly detectors to uncover potential new physical phenomena in each search.

    hep-phEPJC(2025)·8 citations
11. 11*

    Pseudo-Dirac Neutrinos and Relic Neutrino Matter Effect on the High-energy Neutrino Flavor Composition

    P. S. Bhupal Dev🇺🇸 · Pedro A. N. Machado🇺🇸 · Ivan Martinez-Soler🇬🇧

    We show that if neutrinos are pseudo-Dirac, they can potentially affect the flavor ratio predictions for the high-energy astrophysical neutrino flux observed by IceCube. In this context, we point out a novel matter effect induced by the cosmic neutrino background (C$\nu$B) on the flavor ratio composition. Specifically, the active-sterile neutrino oscillations over the astrophysical baseline lead to an energy-dependent flavor ratio at Earth due to the C$\nu$B matter effect, which is in principle distinguishable from the vacuum oscillation effect, provided there is an asymmetry between the neutrino and antineutrino number densities, as well as a local C$\nu$B overdensity. Considering the projected precision of the 3-neutrino oscillation parameter measurements and improved flavor triangle measurements, we show that the next-generation neutrino telescopes, such as KM3NeT and IceCube-Gen2, can in principle probe the pseudo-Dirac neutrino hypothesis and the C$\nu$B matter effect.

    hep-phastro-ph.COastro-ph.HEPLB(2025)·22 citations
12. 12*

    Resonant Conversion of Gravitational Waves in Neutron Star Magnetospheres

    Jamie I. McDonald🇬🇧 · Sebastian A. R. Ellis🇨🇭

    High frequency gravitational waves are the subject of rapidly growing interest in the theoretical and experimental community. In this work we calculate the resonant conversion of gravitational waves into photons in the magnetospheres of neutron stars via the inverse Gertsenshtein mechanism. The resonance occurs in regions where the vacuum birefringence effects cancel the classical plasma contribution to the photon dispersion relation, leading to a massless photon in the medium which becomes kinematically matched to the graviton. We set limits on the amplitude of a possible stochastic background of gravitational waves using X-ray and IR flux measurements of neutron stars. Using Chandra ($2-8\text{keV}$) and NuSTAR ($3-79\text{keV}$) observations of RX J1856.6-3754, we set strain limits $h_c^{\lim }\simeq 10^{-26}-10^{-24}$ in the frequency range $5\times 10^{17}\mathrm{Hz}\lesssim f\lesssim 2\times 10^{19}\text{Hz}$. Our limits are many orders of magnitude stronger than existing constrains from individual neutron stars at the same frequencies. We also use recent JWST observations of the Magnetar 4U 0142+61 in the range $2.7\times 10^{13}\mathrm{Hz}\lesssim f\lesssim 5.9\times 10^{13}\mathrm{Hz}$, setting a limit $h_{\mathrm{c}}^{\lim }\simeq 5\times 10^{-19}$. These constraints are in complementary frequency ranges to laboratory searches with CAST, OSQAR and ALPS II. We expect these limits to be improved both in reach and breadth with a more exhaustive use of telescope data across the full spectrum of frequencies and targets.

    hep-phastro-ph.COastro-ph.HEgr-qcPRD(2024)·23 citations
13. 13*

    Dark Matter from Dark Glueball Dominance

    David McKeen🇨🇦 · Riku Mizuta🇨🇦 · David E. Morrissey🇨🇦 · Michael Shamma🇨🇦

    New gauge forces can play an important role in the evolution of the early universe. In this work we investigate the cosmological implications of a pure Yang-Mills dark sector that is dominantly populated after primordial inflation. Such a dark sector takes the form of a bath of dark gluons at high temperatures, but confines at lower temperatures to produce a spectrum of dark glueballs. These glueballs then undergo a freezeout process such that the remnant population is nearly completely dominated by the lightest state. To reproduce the observed cosmology, this lightest glueball species must decay to the Standard Model to repopulate and reheat it. At leading order, this can occur through a connector operator of dimension-6. In contrast, other glueballs can be parametrically long-lived or stable, and remain as contributors to dark matter or modify the observed cosmology through their later decays. In this work we study the evolution of such dark sectors in detail. We demonstrate that stable remnant glueballs can produce the measured dark matter abundance. We also derive broad constraints on non-Abelian dark sectors from overproduction of remnant glueballs when they are stable or from their destructive impact when they are able to decay.

    hep-phastro-ph.COPRD(2025)·14 citations
14. 14*

    Neutrino emission in cold neutron stars: Bremsstrahlung and modified urca rates reexamined

    Salvatore Bottaro🇮🇱 · Andrea Caputo🇨🇭 · Damiano Fiorillo🇩🇰

    Neutrino emission in cold neutron stars is dominated by the modified urca (murca) process and nucleon-nucleon bremsstrahlung. The standard emission rates were provided by Friman and Maxwell in 1979, effectively based on a chiral Lagrangian framework with pion and rho meson exchange, supplemented by Landau parameters to describe short-range interactions. We reevaluate these rates within the same framework, correcting several errors and removing unnecessary simplifications, notably the triangular approximation - where the Fermi momenta of protons and leptons negligible compared to that of neutrons - in MURCA, and quantify their importance. The impact of rho meson exchange, previously argued to cancel with interference effects, is actually quite relevant. Altogether, the cooling rates are reduced by as much as a factor 2. We provide comprehensive analytical formulas encompassing all contributions, designed for straightforward numerical implementation. Our results are particularly relevant for studies of physics beyond the standard model, where the emission of new particles - such as axions - is typically computed within the same framework we adopt here.

    hep-phastro-ph.HEnucl-thJCAP(2024)·16 citations
15. 15*

    Neutrino masses and mixing from milli-charged dark matter

    Sudip Jana🇩🇪 · Michael Klasen🇩🇪 · Vishnu P.K. · Luca Paolo Wiggering🇩🇪

    We propose a simple extension to the Standard Model, wherein neutrinos naturally attain small Majorana masses through a one-loop radiative mechanism featuring particles within the loops characterized by milli-charges. Unlike the conventional scotogenic model, our approach avoids imposing a discrete symmetry or expanding the gauge sector. The minuscule electric charges ensure the stability of the lightest particle within the loop as a viable dark matter candidate. Our investigation systematically scrutinizes the far-reaching phenomenological implications arising from these minuscule charges.

    hep-phastro-ph.COastro-ph.HEhep-ex+1JCAP(2025)·6 citations
16. 16*

    $\overline{\text{D}}$arkRayNet: Emulation of cosmic-ray antideuteron fluxes from dark matter

    Jan Heisig🇩🇪 · Michael Korsmeier🇸🇪 · Michael Krämer🇩🇪 · Kathrin Nippel🇩🇪 · Lena Rathmann🇩🇪

    Cosmic-ray antimatter, particularly low-energy antideuterons, serves as a sensitive probe of dark matter annihilating in our Galaxy. We study this smoking-gun signature and explore its complementarity with indirect dark matter searches using cosmic-ray antiprotons. To this end, we develop the neural network emulator $\overline{\text{D}}$arkRayNet, enabling a fast prediction of propagated antideuteron energy spectra for a wide range of annihilation channels and their combinations. We revisit the Monte Carlo simulation of antideuteron coalescence and cosmic-ray propagation, allowing us to explore the uncertainties of both processes. In particular, we take into account uncertainties from the ${\Lambda }_b$ production rate and consider two distinctly different propagation models. Requiring consistency with cosmic-ray antiproton limits, we find that AMS-02 shows sensitivity to a few windows of dark matter masses only, most prominently below 20 GeV. This region can be probed independently by the upcoming GAPS experiment. The program package $\overline{\text{D}}$arkRayNet is available on GitHub.

    hep-phastro-ph.HEJCAP(2024)·6 citations
17. 17*

    Majorana phases beyond neutrinoless double beta decay

    Avital Dery🇺🇸 · Stefania Gori🇺🇸 · Yuval Grossman🇺🇸 · Zoltan Ligeti🇺🇸

    The ${\nu }_M\mathrm{SM}$ is defined as the SM extended to include dimension-5 operators. In this model neutrino masses violate lepton number, and two parameters of the lepton mixing matrix, the Majorana phases, are yet to be constrained. One combination of these phases and the neutrino masses, often denoted by $m_{ee}$, is probed by neutrinoless double beta decays ($0\nu \beta \beta$). We explore what information may be obtained beyond $0\nu \beta \beta$, and how it depends on the lightest neutrino mass. We point out that with current central values of the mixing parameters, $\Delta L_e=2$ and $\Delta L_e=\Delta L_{\mu }=1$ (or $\Delta L_e=2$ and $\Delta L_{\mu }=2$) processes cannot simultaneously vanish, providing a no-lose theorem, in principle, for excluding the ${\nu }_M\mathrm{SM}$, even in the case of normal mass ordering.

    hep-phJHEP(2024)·3 citations
18. 18*

    Elastic scattering at $\sqrt{s}=6$ GeV up to $\sqrt{s}=13$ TeV (proton-proton; proton-antiproton; proton-neutron)

    O.V. Selyugin🇷🇺

    In the framework of the Regge-eikonal model of hadron interaction based on the analyticity of the scattering amplitude with taking into account the hadron structure, a simultaneous analysis is carried out of 90 sets of data. These sets include the data were obtained at low energies ($\sqrt{s}>3.6$ GeV and high energies at FNAL, ISR, $SP\bar{P}S$, TEVATRON and LHC with 4326 experimental points, including the data of $A_N$. The energy and momentum transfer dependence of separate sets of data is analyzed on the basis of the eikonalized Born amplitude with taking into account two additional anomalous terms. Different origins of the nonlinear behavior of the slope of the scattering amplitude are compared. No contribution of hard-Pomeron in the elastic hadron scattering is found. The importance of Odderon's contribution is presented. In the framework of the HEGS model, using the electromagnetic and gravitomagnetic form factors, the differential cross sections in the CNI region and at large $t$ are described well in a wide energy region simultaneously. It is shown that the cross-even part includes the soft pomeron and the additional term with a large slope have energy dependence ${\ln }^2(s)$. The cross-odd part includes the maximal odderon term with ${\ln }^2(s)$ and an additional oscillation term with $\ln (s)$. It is shown that the additional terms with large slope are proportional to charge distributions but the maximal odderon term and oscillation term are proportional to matter distributions. Also, a good description of proton-neutron differential scattering with 526 experimental points is obtained on the basis of the amplitudes taken from the analysis of $pp$ and $p\bar{p}$ scattering. A good description of the $A_N$ data was also obtained.

    hep-phhep-exPRD(2024)·9 citations
19. 19*

    Anomalous soft photons: status and perspectives

    R. Bailhache🇩🇪 · D. Bonocore🇩🇪 · P. Braun-Munzinger🇩🇪 · X. Feal🇪🇸 · S. Floerchinger🇩🇪 · J. Klein🇨🇭 · K. Köhler🇩🇪 · P. Lebiedowicz🇵🇱 · C.M. Peter🇩🇪 · R. Rapp🇺🇸 · K. Reygers🇩🇪 · W. Schäfer🇵🇱 and 6 other authors

    This report summarizes the work of the EMMI Rapid Reaction Task Force on "Real and Virtual Photon Production at Ultra-Low Transverse Momentum and Low Mass at the LHC". We provide an overview of the soft-photon puzzle, i.e., of the long-standing discrepancy between experimental data and predictions based on Low's soft-photon theorem, also referred to as "anomalous" soft photon production, and we review the current theoretical understanding of soft radiation and soft theorems. We also focus on low-mass dileptons as a tool for determining the electrical conductivity of the medium produced in high-energy nucleus-nucleus collisions. We discuss how both topics can be addressed with the planned ALICE 3 detector at the LHC.

    ↳ nucl-exhep-exhep-phPhys.Rept.(2024)·10 citations
20. 20*

    On the time-dependent Aharonov-Bohm effect and the 4-dimensional Stokes theorem

    Masashi Wakamatsu🇯🇵

    The time-dependent Aharonov-Bohm (AB) effect considers the situation in which the magnetic flux inside the solenoid changes time-dependently. Different from the standard AB-effect, the problem is unexpectedly subtle and not easy to solve without any doubt, which is the reason why it is still in a state of unsettlement even theoretically. The difficulty originates from the fact that its theoretical analysis requires line-integrals of the time-dependent vector potential along paths in the 4-dimensional Minkowski space. Owing to the 4-dimensional Stokes theorem, this closed line-integral of the vector potential can be related to the integral of the electric and magnetic fields over the 2-dimensional area, the boundary of which is given by the above-mentioned closed path. The central controversy concerns the success or failure of the claim by Singleton and collaborators based on the 4-dimensional Stokes theorem, which states that the time-dependent part of the AB-phase shift due to the magnetic vector potential is precisely cancelled by the effect of induced electric field generated by the time-variation of the magnetic flux. In the present paper, we carefully reanalyze their cancellation argument by going back to the basic quantum mechanical analysis of the charged particle motion under the presence of the time-dependent external electromagnetic potential combined with more careful treatment of the 4-dimensional Stokes theorem. Careful analysis of the 4-dimensional Stokes theorem shows that the cancellation argument by Singleton et al. is partially correct but their central claim that only the time-independent part of the magnetic field contributes to the AB-phase shift so that there is no time-dependent AB-effect is not justified, thereby supporting likely existence of the time-dependent AB-effect.

    ↳ quant-phhep-phnucl-thphysics.ed-phAnnals Phys.(2025)·5 citations
21. 21*

    Timing and Scintillation Studies of Pulsars in Globular Cluster M3 (NGC 5272) with FAST

    Baoda Li🇨🇳 · Li-yun Zhang🇨🇳 · Jumei Yao · Dejiang Yin · Ralph P. Eatough · Minghui Li · Yifeng Li🇨🇳 · Yujie Lian · Yu Pan🇨🇳 · Yinfeng Dai · Yaowei Li · Xingnan Zhang🇨🇳 and 7 other authors

    We present the phase-connected timing solutions of all the five pulsars in globular cluster (GC) M3 (NGC 5272), namely PSRs M3A to F (PSRs J1342+2822A to F), with the exception of PSR M3C, from FAST archival data. In these timing solutions, those of PSRs M3E, and F are obtained for the first time. We find that PSRs M3E and F have low mass companions, and are in circular orbits with periods of 7.1 and 3.0 days, respectively. For PSR M3C, we have not detected it in all the 41 observations. We found no X-ray counterparts for these pulsars in archival Chandra images in the band of 0.2-20 keV. We noticed that the pulsars in M3 seem to be native. From the Auto-Correlation Function (ACF) analysis of the M3A's and M3B's dynamic spectra, the scintillation timescale ranges from $7.0\pm 0.3$ min to $60.0\pm 0.6$ min, and the scintillation bandwidth ranges from $4.6\pm 0.2$ MHz to $57.1\pm 1.1$ MHz. The measured scintillation bandwidths from the dynamic spectra indicate strong scintillation, and the scattering medium is anisotropic. From the secondary spectra, we captured a scintillation arc only for PSR M3B with a curvature of $649\pm 23{\mathrm{m}}^{-1}{\mathrm{mHz}}^{-2}$.

    ↳ astro-ph.HEhep-phApJ(2024)·10 citations
22. 22*

    Neutron Stars in Aether Scalar-Tensor Theory

    Christopher Reyes🇺🇸 · Jeremy Sakstein🇺🇸

    Aether Scalar-Tensor theory is a modification of general relativity proposed to explain galactic and cosmological mass discrepancies conventionally attributed to dark matter.~The theory is able to fit the cosmic microwave background and the linear matter power spectrum.~In this work, we derive the Tolman-Oppenheimer-Volkoff equation in this theory and solve it for realistic nuclear equations of state to predict the mass-radius relation of neutron stars.~We find solutions that are compatible with all current observations of neutron stars.

    ↳ gr-qcastro-ph.COastro-ph.HEhep-phPRD(2024)·5 citations
23. 23*

    Hint to Supersymmetry from GR Vacuum

    Gia Dvali🇩🇪 · Archil Kobakhidze🇦🇺 · Otari Sakhelashvili🇦🇺

    The $S$-matrix formulation of gravity suggests that the $\theta$-vacuum structure must not be sustained by the theory. We point out that, when applied to the vacuum of general relativity, this criterion hints to supersymmetry. The topological susceptibility of gravitational vacuum induced by Eguchi-Hanson instantons can be eliminated neither by spin-$1/2$ fermions nor by an axion coupled via them since such fermions do not provide instanton zero modes. Instead, the job is done by a spin-$3/2$ fermion, hence realizing a local supersymmetry. This scenario also necessitates the spontaneous breaking of supersymmetry and predicts the existence of axion of $R$-symmetry which gets mass exclusively from the gravitational instantons. The $R$-axion can be a viable dark matter candidate. Matching between the index and the anomaly imposes a constraint that spin-$1/2$ fermions should not contribute to the chiral gravitational anomaly.

    ↳ hep-thgr-qchep-phPRD(2024)·18 citations
24. 24*

    Neural Network Emulation of Flow in Heavy-Ion Collisions at Intermediate Energies

    Nicholas Cox🇺🇸 · Xavier Grundler🇺🇸 · Bao-An Li🇺🇸

    Applications of new techniques in machine learning are speeding up progress in research in various fields. In this work, we construct and evaluate a deep neural network (DNN) to be used within a Bayesian statistical framework as a faster and more reliable alternative to the Gaussian Process (GP) emulator of an isospin-dependent Boltzmann-Uehling-Uhlenbeck (IBUU) transport model simulator of heavy-ion reactions at intermediate beam energies. We found strong evidence of DNN being able to emulate the IBUU simulator's prediction on the strengths of protons' directed and elliptical flow very efficiently even with small training datasets and with accuracy about ten times higher than the GP. Limitations of our present work and future improvements are also discussed.

    ↳ nucl-thhep-phnucl-exPRC(2024)·6 citations
25. 25*

    Upper Bounds on the Mass of Fundamental Fields from Primordial Universe

    Hassan Firouzjahi🇮🇷

    We study the fluctuations in the vacuum zero point energy associated to quantum fields and their statistical distributions during inflation. It is shown that the perturbations in the vacuum zero point energy have large amplitudes which are highly non-Gaussian. The effects of vacuum zero point fluctuations can be interpreted as the loop corrections in primordial power spectrum and bispectrum. Requiring that the primordial curvature perturbation to remain nearly Gaussian and the loop corrections to be under perturbative control impose strong upper bounds on the mass of fundamental fields during inflation. These bounds depend on the hierarchy of the masses in the theory such as whether or not the masses are at the similar orders. While the mass of the heaviest field in the hierarchy may not be constrained but it is shown that a combination of the masses of the fields can not be much heavier than the Hubble scale during inflation, otherwise their vacuum zero point fluctuations induce large non-Gaussianities in primordial perturbations. Considering the observational upper bound on tensor to scalar ratio, we conclude that this combined mass scale is lighter than $10^{14}$ GeV.

    ↳ astro-ph.COgr-qchep-phhep-thApJ(2025)·1 citation
26. 26*

    ${\Lambda }_{\mathrm{s}}$CDM cosmology: Alleviating major cosmological tensions by predicting standard neutrino properties

    Anita Yadav🇮🇳 · Suresh Kumar🇮🇳 · Cihad Kibris🇹🇷 · Ozgur Akarsu🇹🇷

    We investigate a two-parameter extension of the ${\Lambda }_{\mathrm{s}}$CDM model by allowing variations in the effective number of neutrino species $N_{\mathrm{eff}}$ and their total mass $\sum m_{\nu }$. Our motivation is twofold: (i) to examine whether ${\Lambda }_{\mathrm{s}}$CDM retains its success in fitting the data and addressing major cosmological tensions, without suggesting a need for a deviation from the standard model of particle physics, and (ii) to determine whether the data indicate new physics that could potentially address cosmological tensions, either in the post-recombination universe through the late-time mirror AdS-dS transition, or in the pre-recombination universe through modifications in the standard values of $N_{\mathrm{eff}}$ and $\sum m_{\nu }$, or both. Within the extended ${\Lambda }_{\mathrm{s}}$CDM model, referred to as ${\Lambda }_{\mathrm{s}}$CDM+$N_{\mathrm{eff}}$+$\sum m_{\nu }$, we find no significant tension when considering the Planck-alone analysis. We observe that incorporating BAO data limits the further success of the ${\Lambda }_{\mathrm{s}}$CDM extension. However, the weakly model-dependent BAOtr data, along with Planck and Planck+PP\&SH0ES, favor $H_0\sim 73\mathrm{km}{\mathrm{s}}^{-1}\mathrm{Mp}{\mathrm{c}}^{-1}$. In cases where BAOtr dataset is used, the mirror AdS-dS transition is very effective in providing enhanced $H_0$ values, and thus the model requires no significant deviation from the standard value of $N_{\mathrm{eff}}=3.044$. Both the $H_0$ and $S_8$ tensions are effectively addressed, with some compromise in the case of the Planck+BAO dataset. Finally, the upper bounds obtained on $\sum m_{\nu }\lesssim 0.5$~eV are fully compatible with neutrino oscillation experiments. Our findings provide evidence that late-time physics beyond $\Lambda$CDM, such as ${\Lambda }_{\mathrm{s}}$CDM, without altering the standard pre-recombination universe, can suffice to alleviate the major cosmological tensions.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2025)·53 citations
27. 27*

    Electrical conductivity of the Quark-Gluon Plasma in the presence of strong magnetic fields

    Giorgio Almirante🇫🇷 · Nikita Astrakhantsev🇨🇭 · V. V. Braguta🇷🇺 · Massimo D'Elia🇮🇹 · Lorenzo Maio🇮🇹 · Manuel Naviglio🇮🇹 · Francesco Sanfilippo🇮🇹 · Anton Trunin🇮🇹

    We compute the electrical conductivity of the strongly interacting medium in the presence of strong magnetic background fields, $eB=4,9Ge{V}^2$, and for different values of the temperature, both in the confined and in the deconfined Quark-Gluon Plasma (QGP) phase. The conductivity is obtained from the Euclidean lattice time correlator of the electrical current, computed on gauge configurations sampled from Monte-Carlo simulations of an improved staggered discretization of $N_f=2+1$ QCD. We perform the inverse Laplace transform of the correlator adopting a recently-proposed version of the standard Backus--Gilbert procedure for the inversion. The results obtained in the QGP phase show a sizable enhancement of the conductivity in the direction parallel to the magnetic field, as well as a suppression in the direction orthogonal to it. Such enhancement could be attributed to the manifestation of the Chiral Magnetic Effect (CME): following this guess, we extract the behaviour of the relaxation time of this process, extrapolate it to the continuum limit and compare it to previous results, finding it lower than expected in the explored range of temperatures.

    ↳ hep-lathep-phPRD(2025)·19 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.