Wed·Mar 6, 2024Wednesday·March 6, 2024

1. 01*

   Impact of New Experimental Data on the C2HDM: the Strong Interdependence between LHC Higgs Data and the Electron EDM

   Thomas Biekötter🇩🇪 · Duarte Fontes🇺🇸 · Margarete Mühlleitner🇩🇪 · Jorge C. Romão🇵🇹 · Rui Santos🇵🇹 · João P. Silva🇵🇹

   The complex two-Higgs doublet model (C2HDM) is one of the simplest extensions of the Standard Model with a source of CP-violation in the scalar sector. It has a ${\mathbb{Z}}_2$ symmetry, softly broken by a complex coefficient. There are four ways to implement this symmetry in the fermion sector, leading to models known as Type-I, Type-II, Lepton-Specific and Flipped. In the latter three models, there is a priori the surprising possibility that the 125 GeV Higgs boson couples mostly as a scalar to top quarks, while it couples mostly as a pseudoscalar to bottom quarks. This ``maximal'' scenario was still possible with the data available in 2017. Since then, there have been more data on the 125 GeV Higgs boson, direct searches for CP-violation in angular correlations of $\tau$-leptons produced in Higgs boson decays, new results on the electron electric dipole moment, new constraints from LHC searches for additional Higgs bosons and new results on $b\to s\gamma$ transitions. Highlighting the crucial importance of the physics results of LHC's Run 2, we combine all these experiments and show that the ``maximal'' scenario is now excluded in all models. Still, one can have a pseudoscalar component in $h\tau \bar{\tau }$ couplings in the Lepton-Specific case as large as $87\%$ of the scalar component for all mass orderings of the neutral scalar bosons.

   hep-phJHEP(2024)·23 citations
2. 02*

   Electroweak metastability and Higgs inflation

   Isabella Masina🇮🇹 · Mariano Quiros🇪🇸

   Extrapolating the Standard Model Higgs potential at high energies, we study the barrier between the electroweak and Planck scale minima. The barrier arises by taking the central values of the relevant experimental inputs, that is the strong coupling constant and the top quark and Higgs masses. We then extend the Standard Model by including a non-minimal coupling to gravity, and explore the phenomenology of the Higgs inflation model. We point out that even configurations that would be metastable in the Standard Model, become viable for inflation if the non-minimal coupling is large enough to flatten the Higgs potential at field values below the barrier; we find that the required value of the non-minimal coupling is smaller than the one needed for the conventional Higgs inflation scenario (which relies on a stable Standard Model Higgs potential, without any barrier); in addition, values of the top mass which are slightly larger than those required in the conventional scenario are allowed.

   hep-phastro-ph.COEPJC(2024)·13 citations
3. 03*

   Thermal effects on sound velocity peak and conformality in isospin QCD

   Ryuji Chiba🇯🇵 · Toru Kojo🇯🇵 · Daiki Suenaga🇯🇵

   We study thermal effects on equations of state (EOS) in isospin QCD, utilizing a quark-meson model coupled to a Polyakov loop. The quark-meson model is analyzed at one-loop that is the minimal order to include quark substructure constraints on pions which condense at finite isospin density. In the previous study we showed that the quark-meson model at zero temperature produces the sound velocity peak and the negative trace anomaly in the domain between the chiral effective theory regime at low density and the perturbative QCD regime at high density, in reasonable agreement with lattice simulations. We now include thermal effects from quarks in the Polyakov loop background and examine EOS, especially the sound velocity and trace anomaly along isentropic trajectories. At large isospin density, there are three temperature windows; (i) the pion condensed region with almost vanishing Polyakov loops, (ii) the pion condensed region with finite Polyakov loops, and (iii) the quark gas without pion condensates. In the domain (i), the gap associated with the pion condensate strongly quenches thermal excitations. As the system approaches the domain (ii), thermal quarks, which behave as non-relativistic particles, add energy density but little pressure, substantially reducing the sound velocity to the value less than the conformal value while increasing the trace anomaly toward the positive value. Approaching the domain (iii), thermal quarks become more relativistic as pion condensates melt, increasing sound velocity toward the conformal limit. Corrections from thermal pions are also briefly discussed.

   hep-phhep-latnucl-thPRD(2024)·15 citations
4. 04*

   Femtoscopy analysis of ultra-soft pion trap at energies available at the CERN Large Hadron Collider

   W. Rzesa🇵🇱 · G. Kornakov🇵🇱 · A.R. Kisiel🇵🇱 · Yu.M. Sinyukov🇺🇦 · V.M. Shapoval🇺🇦

   Femtoscopy studies of pion radiation in heavy-ion collisions have been conducted extensively at all available collider energies, both theoretically and experimentally. In all these studies a special interest is given to $m_T$ dependency of pion femtoscopy radii, usually approximated by a power-law function at transverse momenta above 200 MeV/$c$. However, the radii behaviour has been much less explored for the ultra-soft pions, possessing the transverse momentum comparable to or lower than the pion mass. For many experimental setups this region is difficult to measure. In this work we present theoretical calculations of pion emission in the ultra-soft region in the two hybrid models -- iHKM and LHYQUID+THERMINATOR2. Along with the particle transverse momentum spectra, we present the calculated femtoscopy radii, both in one-dimensional and three-dimensional representations. We investigate the radii dependence on pair $m_T$ and observe, in particular, a departure from the power-law behaviour at ultra-soft momenta, potentially reflecting a decoupling of such slow pions from the rest of collectively expanding system. We provide the theoretical interpretation of this result and discuss its significance, in particular, for the ongoing non-identical particle femtoscopy analysis for pairs consisting of a pion and a baryon (or of a pion and a charmed meson).

   hep-phPRC(2024)·3 citations
5. 05*

   Limits on scalar dark matter interactions with particles other than the photon via loop corrections to the scalar-photon coupling

   V. V. Flambaum🇦🇺 · I. B. Samsonov🇦🇺

   There is limited information about the interaction strength of a scalar dark matter candidate with hadrons and leptons for a scalar particle mass exceeding $10^{-3}$ eV while its interaction with photon is well studied. The scalar-photon coupling constant receives quantum corrections from one-loop Feynman diagrams which involve the scalar-lepton, scalar-quark, and scalar-W boson vertices. We calculate these one-loop quantum corrections and find new limits on the scalar particle interactions with electron, muon, tau, quarks, nucleons, gluons, Higgs, and W bosons by re-purposing the results of experiments measuring the scalar-photon interaction. Limits on interactions of heavy leptons and quarks have been obtained for the first time, and limits on other interactions in certain mass intervals are 2 to 15 orders of magnitude stronger than those presented in previous publications and exclude the resolution of the muon $g-2$ anomaly with scalar particle.

   hep-phastro-ph.COphysics.atom-phPRD(2024)·6 citations
6. 06*

   Light Thermal Dark Matter Beyond $p$-Wave Annihilation in Minimal Higgs Portal Model

   Yu-Tong Chen🇨🇳 · Shigeki Matsumoto🇯🇵 · Tian-Peng Tang🇨🇳 · Yue-Lin Sming Tsai🇨🇳 · Lei Wu🇨🇳

   This study explores a minimal renormalizable dark matter (DM) model, incorporating a sub-GeV Majorana DM and a singlet scalar particle $\varphi$. Using scalar and pseudo-scalar interactions (couplings $c_s$ and $c_p$), we investigate implications for DM detection, considering $s$-wave, $p$-wave, and combined ($s$+$p$ wave) contributions in DM annihilation cross-section, as well as loop-correction contributions to DM-nucleon elastic scattering. Identifying a broad parameter space ($10\mathrm{MeV}<{\mathrm{m}}_{\chi }\lesssim {\mathrm{m}}_{\varphi }$) within the $2\sigma$ allowed region, we explore scenarios ($\left|c_s\right|\gg \left|c_p\right|$, $\left|c_s\right|\ll \left|c_p\right|$, and $\left|c_s\right|\approx \left|c_p\right|$). We find that (i) a non-zero pseudo-scalar coupling alleviates direct detection constraints as a comparison with the previous pure scalar coupling case; (ii) CMB observations set stringent limits on pseudo-scalar interaction dominant cases, making $s$-wave annihilation viable only for $m_{\chi }>1\mathrm{GeV}$; (iii) the preferred $\varphi$-resonance region can be tested in the future indirect detection experiments, such as e-ASTROGAM.

   hep-phastro-ph.HEJHEP(2024)·17 citations
7. 07*

   Attempt at Constructing a Model of Grand Gauge-Higgs Unification with Family Unification

   Nobuhito Maru🇯🇵 · Ryujiro Nago🇯🇵

   We discuss a possibility whether a model of grand gauge-Higgs unification incorporating family unification in higher dimensions can be constructed. We first extend a five dimensional $SU(6)$ grand gauge-Higgs unification model to a five dimensional $SU(7)$ grand gauge-Higgs unification model compactified on an orbifold $S^1/Z_2$ to obtain three generations of quarks and leptons after symmetrybreaking of the larger family unified gauge group. A prescription of constructing a six dimensional $SU(N)$ grand gauge-Higgs unification model including a five dimensional $SU(7)$ grand gauge-Higgs unification after compactifying the sixth dimension on an orbifold $S^1/Z_2$ is given. We find a six dimensional $SU(14)$ grand gauge-Higgs unification model with a set of representations containing three generations of quarks and leptons.

   hep-phPRD(2024)·5 citations
8. 08*

   On instabilities of perturbations in some homogeneous color-electric and -magnetic backgrounds in SU(2) gauge theory

   Divyarani C. Geetha🇳🇴 · Anders Tranberg🇳🇴

   We consider the instabilities of field perturbations around a homogeneous background color-electric and/or -magnetic field in SU(2) pure gauge theory. We investigate a number of distinct cases of background magnetic and electric fields, and compute the dispersion relations in the linearised theory, identifying stable and unstable momentum modes. In the case of a net homogeneous non-abelian B-field, we compute the non-linear (quadratic and cubic) corrections to the equation of motion, and quantify to what extent the instabilities are tempered by these non-linearities.

   hep-phPRD(2024)·0 citations
9. 09*

   Rare $B$ and $K$ decays in a scotogenic model

   Chuan-Hung Chen🇹🇼 · Cheng-Wei Chiang🇹🇼

   A scotogenic model can radiatively generate the observed neutrino mass, provide a dark matter candidate, and lead to rare lepton flavor-violating processes. We aim to extend the model to establish a potential connection to the quark flavor-related processes within the framework of scotogenesis, enhancing the unexpectedly large branching ratio (BR) of $B^{+}\to K^{+}\nu \bar{\nu }$, observed by Belle II Collaboration. Meanwhile, the model can address tensions between some experimental measurements and standard model (SM) predictions in flavor physics, such as the muon $g-2$ excess and the higher BR of $B_s\to {\mu }^{-}{\mu }^{+}$. We introduce in the model the following dark particles: a neutral singlet Dirac-type lepton ($N$); two inert Higgs doublets (${\eta }_{1,2}$), with one of which carrying a lepton number; a charged singlet dark scalar $({\chi }^{+})$, and a singlet vector-like up-type dark quark ($T$). The first two entities are responsible for the radiative neutrino mass, and ${\chi }^{+}$ couples to right-handed quarks and leptons and can resolve the tensions existing in muon $g-2$ and $B_s\to {\mu }^{-}{\mu }^{+}$. Furthermore, the BR of $B^{+}\to K^{+}\nu \bar{\nu }$ can be enhanced up to a factor of 2 compared to the SM prediction through the mediations of the dark $T$ and the charged scalars. In addition, we also study the impacts on the $K\to \pi \nu \bar{\nu }$ decays.

   hep-phhep-exPRD(2024)·19 citations
10. 10*

    Microscopic parametrization of the near threshold oscillations of the nucleon time-like effective electromagnetic form factors

    Francesco Rosini🇮🇹 · Simone Pacetti🇮🇹 · Olga Shekhovtsova🇮🇹 · Egle Tomasi-Gustafsson🇫🇷

    We present an analysis of the recent near threshold BESIII data for the nucleon time-like effective form factors. The damped oscillation emerging from the subtraction of the dipole formula is treated in non-perturbative-QCD, making use of the light cone distribution amplitudes expansion. Non-perturbative effects are accounted for by considering Q2-dependent coefficients in such expansions, whose free parameters are determined by fitting to the proton and neutron data. Possible implications and future analysis have been discussed.

    hep-phhep-exnucl-thEPJA(2024)·3 citations
11. 11*

    Higgs couplings in SMEFT via Zh production at the HL-LHC

    Subhaditya Bhattacharya🇮🇳 · Sanjoy Biswas🇮🇳 · Abhik Sarkar🇮🇳

    We study the Higgs couplings involved in the $Zh$ associated production mode at the Large Hadron Collider (LHC) in presence of Higgs-gauge boson coupling modifiers via $\kappa$ framework, and dimension 6 Standard Model Effective Theory (SMEFT) operators. The analysis is performed mainly in context of the HL-LHC (with $\sqrt{s}=$14 TeV and luminosity 3000 $f{b}^{-1}$) setup using cut based as well as machine learning techniques. The analysis shows significant betterment in the signal significance by using the machine learning technique. We also do a ${\chi }^2$ analysis, which reveals an appreciable change in the sensitivity of the coupling modifiers due to the presence of effective operators, in particular due to the $qqZh$ Higgs-current interactions. The dipole operators concerning the same vertex, combine quarks of different chiralities and does not interfere with the SM diagrams, hence contributing only at $\mathcal{O}({\Lambda }^{-4})$. In order to observe better sensitivity for this class of operators, we need to move to higher center-of-mass energy, where the effects of both Higgs-current and dipole 4-point interactions are more prominent.

    hep-phPRD(2025)·4 citations
12. 12*

    $N$-jettiness soft function at next-to-next-to-leading order in perturbative QCD

    Prem Agarwal🇩🇪 · Kirill Melnikov🇩🇪 · Ivan Pedron🇩🇪

    We derive a compact representation of the renormalized $N$-jettiness soft function that is free of infrared and collinear divergences through next-to-next-to-leading order in perturbative QCD. The number of hard partons $N$ is a parameter in the formula for the finite remainder. Cancellation of all infrared and collinear singularities between the bare soft function and its renormalization matrix in color space is demonstrated analytically.

    hep-phJHEP(2024)·15 citations
13. 13*

    Probing Light Inelastic Dark Matter from Direct Detection

    Hong-Jian He🇨🇳 · Yu-Chen Wang🇨🇳 · Jiaming Zheng🇨🇳

    For dark matter (DM) direct detections, the kinematic effects such as those of the inelastic scattering can play important role in light DM searches. The light DM detection is generally difficult because of its small recoil energy. But the recoil energy of the exothermic inelastic DM scattering could exceed the detection threshold due to the contribution from the DM mass-splitting, making the direct detection of sub-GeV DM feasible. In this work, we systematically study signatures of the light exothermic inelastic DM from the recoil spectra including both the DM-electron scattering and Migdal effect. Such inelastic DM has mass around (sub-)GeV scale with DM mass-splitting of $O(1-10^2)$keV. We analyze the direct detection sensitivities to such light inelastic DM. For different inelastic DM masses and mass-splittings, we find that the DM-electron recoil and Migdal effect can contribute significantly and differently to the direct detection signatures. The DM-lepton and/or DM-quark interactions may vary for different DM models, and their interplay leads to a diversity in the recoil spectra. Hence, it is important to perform a combined analysis to include both the DM-electron recoil and Migdal effect. We further demonstrate that this analysis has strong impacts on the cosmological and laboratory bounds for the inelastic DM.

    hep-phastro-ph.COhep-exPhys.Dark Univ.(2024)·9 citations
14. 14*

    The Density of Relic Neutrinos Near the Surface of Earth

    Andrei Gruzinov🇺🇸 · Mehrdad Mirbabayi🇮🇹

    It has been claimed that matter effects cause an asymmetry in the density of relic neutrinos versus antineutrinos near the surface of Earth, of order $O(G_F^{1/2})\sim 10^{-4}$, with the vertical extent $\sim 10$m. We argue that the effect is of order $O(G_F)\sim 10^{-8}$, with the vertical extent $\sim 1$mm.

    hep-phastro-ph.CO8 citations
15. 15*

    Nonthermal Heavy Dark Matter from a First-Order Phase Transition

    Gian F. Giudice🇨🇭 · Hyun Min Lee🇰🇷 · Alex Pomarol🇪🇸 · Bibhushan Shakya🇩🇪

    We study nonthermal production of heavy dark matter from the dynamics of the background scalar field during a first-order phase transition, predominantly from bubble collisions. In scenarios where bubble walls achieve runaway behavior and get boosted to very high energies, we find that it is possible to produce dark matter with mass several orders of magnitude above the symmetry breaking scale or the highest temperature ever reached by the thermal plasma. We also demonstrate that the existing formalism for calculating particle production from bubble dynamics in a first-order phase transition is not gauge invariant, and can lead to spurious results. While a rigorous and complete resolution of this problem is still lacking, we provide a practical prescription for the computation that avoids unphysical contributions and should provide reliable order-of-magnitude estimates of this effect. Furthermore, we point out the importance of three-body decays of the background field excitations into scalars and gauge bosons, which provide the dominant contributions at energy scales above the scale of symmetry breaking. Using our improved results, we find that scalar, fermion, and vector dark matter are all viable across a large range of mass scales, from O(10) TeV to a few orders of magnitude below the Planck scale, and the corresponding phase transitions can be probed with current and future gravitational wave experiments.

    hep-phastro-ph.COJHEP(2024)·50 citations
16. 16*

    Signatures of ultralight bosons in the orbital eccentricity of binary black holes

    Mateja Bošković🇩🇪 · Matthias Koschnitzke🇩🇪 · Rafael A. Porto🇩🇪

    We show that the existence of clouds of ultralight particles surrounding black holes during their cosmological history as members of a binary system can leave a measurable imprint on the distribution of masses and orbital eccentricities observable with future gravitational-wave detectors. Notably, we find that for nonprecessing binaries with chirp masses $\mathcal{M}\lesssim 10M_{\odot }$, formed exclusively in isolation, larger-than-expected values of the eccentricity, i.e. $e\gtrsim 10^{-2}$ at gravitational-wave frequencies $f_{\mathrm{GW}}\simeq 10^{-2}$Hz, would provide tantalizing evidence for a new particle of mass between $[0.5,2.5]\times 10^{-12}$eV in nature. The predicted evolution of the eccentricity can also drastically affect the in-band phase evolution and peak frequency. These results constitute unique signatures of boson clouds of ultralight particles in the dynamics of binary black holes, which will be readily accessible with the Laser Interferometer Space Antenna, as well as future mid-band and Deci-hertz detectors.

    ↳ gr-qcastro-ph.COastro-ph.HEhep-ph+1PRL(2024)·56 citations
17. 17*

    ACE Science Workshop Report

    Stefania Gori🇺🇸 · Nhan Tran🇺🇸 · Karri DiPetrillo🇺🇸 · Bertrand Echenard🇺🇸 · Jeffrey Eldred🇺🇸 · Roni Harnik🇺🇸 · Pedro Machado🇺🇸 · Matthew Toups🇺🇸 · Robert Bernstein🇺🇸 · Innes Bigaran🇺🇸 · Cari Cesarotti🇺🇸 · Bhaskar Dutta🇺🇸 and 11 other authors

    We summarize the Fermilab Accelerator Complex Evolution (ACE) Science Workshop, held on June 14-15, 2023. The workshop presented the strategy for the ACE program in two phases: ACE Main Injector Ramp and Target (MIRT) upgrade and ACE Booster Replacement (BR) upgrade. Four plenary sessions covered the primary experimental physics thrusts: Muon Collider, Neutrinos, Charged Lepton Flavor Violation, and Dark Sectors. Additional physics and technology ideas were presented from the community that could expand or augment the ACE science program. Given the physics framing, a parallel session at the workshop was dedicated to discussing priorities for accelerator R\&D. Finally, physics discussion sessions concluded the workshop where experts from the different experimental physics thrusts were brought together to begin understanding the synergies between the different physics drivers and technologies. In December of 2023, the P5 report was released setting the physics priorities for the field in the next decade and beyond, and identified ACE as an important component of the future US accelerator-based program. Given the presentations and discussions at the ACE Science Workshop and the findings of the P5 report, we lay out the topics for study to determine the physics priorities and design goals of the Fermilab ACE project in the near-term.

    ↳ hep-exhep-ph7 citations
18. 18*

    The quest to discover supersymmetry at the ATLAS experiment

    ATLAS Collaboration

    The search for supersymmetry with the ATLAS experiment at the CERN Large Hadron Collider intensified after the discovery of the Higgs boson in 2012. The search programme expanded in both breadth and depth, profiting from the increased integrated luminosity and higher centre-of-mass energy of Run 2, and gaining new sensitivity to unexplored areas of supersymmetry parameter space through the use of new experimental signatures and innovative analysis techniques. This report summarises the supersymmetry searches at ATLAS using up to 140 fb${}^{-1}$ of $pp$ collisions at $\sqrt{s}=13$ TeV, including the limits set on the production of gluinos, squarks, and electroweakinos for scenarios either with or without R-parity conservation, and including models where some of the supersymmetric particles are long-lived.

    ↳ hep-exhep-phPhys.Rept.(2025)·90 citations
19. 19*

    Macroscopic neutrinoless double beta decay: long range quantum coherence

    Gordon Baym🇺🇸 · Jen-Chieh Peng🇺🇸

    We re-introduce, in light of our modern understanding of neutrinos, the concept of ``macroscopic neutrinoless double beta decay" (MDBD) for Majorana neutrinos. In this process an antineutrino produced by a nucleus undergoing beta decay, $X\to Y+e^{-}+{\bar{\nu }}_e$, is absorbed as a neutrino by another identical $X$ nucleus via the inverse beta decay reaction, ${\nu }_e+X\to e^{-}+Y$. The distinct signature of MDBD is that the total kinetic energy of the two electrons equals twice the endpoint energy of single beta decay. The amplitude for MDBD, a coherent sum over the contribution of different mass states of the intermediate neutrinos, reflects quantum coherence over macroscopic distances, and is a new macroscopic quantum effect. We evaluate the rate of MDBD for a macroscopic sample of ``$X$" material, e.g., tritium, acting both as the source and the target. The accidental background for MDBD originating from two separate single beta decays, which contains two final state neutrinos, can be readily rejected by measuring the energy of the detected two electrons. We discuss the similarities and differences between the MDBD and conventional neutrinoless double beta decay.

    ↳ nucl-thhep-exhep-phnucl-exNPB(2025)·1 citation
20. 20*

    Double Deeply Virtual Compton Scattering at Jefferson Lab Hall A

    Marie Boër🇺🇸 · Debaditya Biswas🇺🇸

    This paper presents our project and perspectives to measure for the first time beam spin asymmetries from Double Deeply Virtual Compton Scattering in the $eP\to e^{\prime }{P}^{\prime }{\mu }^{+}{\mu }^{-}$ reaction at Jefferson Lab. Our goal is to constrain the so-called Generalized Parton Distribution (GPDs) in a kinematic region that isn't accessible from other reactions, such as Deeply Virtual Compton Scattering, to allow for their extrapolation to "zero skewness", i.e. at a specific kinematic point enabling for tomographic interpretations of the nucleon's partonic structure. We are discussing DDVCS phenomenology and our approach, as well as our experimental project aimed at complementing the SoLID experiment at JLab Hall A with a new muon detector.

    ↳ nucl-exhep-phPoS(2024)·1 citation
21. 21*

    The Mass Gap of the Space-time and its Shape

    Ahmed Farag Ali🇺🇸

    Snyder's quantum space-time which is Lorentz invariant is investigated. It is found that the quanta of space-time have a positive mass that is interpreted as a positive real mass gap of space-time. This mass gap is related to the minimal length of measurement which is provided by Snyder's algebra. Several reasons to consider the space-time quanta as a 24-cell are discussed. Geometric reasons include its self-duality property and its 24 vertices that may represent the standard model of elementary particles. The 24-cell symmetry group is the Weyl/Coxeter group of the $F_4$ group which was found recently to generate the gauge group of the standard model. It is found that 24-cell may provide a geometric interpretation of the mass generation, Avogadro number, color confinement, and the flatness of the observable universe. The phenomenology and consistency with measurements is discussed.

    ↳ hep-thgr-qchep-phFortsch.Phys.·4 citations
22. 22*

    Impact of (magneto-)thermoelectric effect on diffusion of conserved charges in hot and dense hadronic matter

    He-Xia Zhang🇨🇳 · Ke-Ming Shen🇨🇳 · Yu-Xin Xiao🇨🇳 · Ben-Wei Zhang🇨🇳

    We investigate the thermoelectric effect, which describes the generation of an electric field induced by temperature and conserved charge chemical potential gradients, in the hot and dense hadronic matter created in heavy-ion collisions. Utilizing the Boltzmann kinetic theory within the repulsive mean-field hadron resonance gas model, we evaluate both the diffusion thermopower matrix and diffusion coefficient matrix for the baryon number ($B$), electric charge ($Q$), and strangeness ($S$). The Landau-Lifshitz choice for the rest frame of the fluid is enforced in the derivation. We find that the thermoelectric effect hinders the diffusion processes of multiple conserved charges, particularly reducing the coupling between electric charge and baryon number (strangeness) in baryon (strangeness) diffusion. Given that the repulsive mean-field interactions between hadrons have a significant effect on the diffusion thermopower matrix and diffusion coefficient matrix in the baryon-rich region, we extend the investigation to include the impact of magnetic fields, analyzing the magneto-thermoelectric effect on both the diffusion coefficient matrix and the Hall-like diffusion coefficient matrix. The sensitivities of the magnetic field-dependent diffusion thermopower matrix and magneto-thermoelectric modified diffusion coefficient matrix to the choices of various transverse conditions are also studied.

    ↳ nucl-thhep-phhep-thPRD(2024)·4 citations
23. 23*

    Nuclear medium effects on the properties of $\Lambda (1405)$

    J. Y. Süngü🇹🇷 · N. Er🇹🇷

    We study the $\Lambda (1405)$ resonance with $I(J^P)=0(1/2^{-})$ in the context of the pentaquark hypothesis in the nuclear medium. For the investigation of the influence of the nuclear medium on the physical parameters of $\Lambda (1405)$, we propose a molecular-type structure involving $K^{-}p$ and ${\bar{K}}^{0}n$ admixtures, correlated with the nuclear matter density. Our analysis reveals a substantial shift in both mass and residue, approximately $20\%$ and $38\%$, respectively. These findings have significant implications for experimental researchers aimed at identifying in-medium characteristics of hyperon resonances.

    ↳ nucl-thhep-phJ.Phys.G(2024)·4 citations
24. 24*

    Kinetic temperature and radial flow velocity estimation using identified hadrons and light (anti-)nuclei produced in relativistic heavy-ion collisions at RHIC and LHC

    Junaid Tariq🇵🇰 · M. U. Ashraf🇧🇪 · Grigory Nigmatkulov🇺🇸

    We report the investigation of the kinetic freeze-out properties of identified hadrons (${\pi }^{\pm }$, $K^{\pm }$ and $p(\bar{p})$) along with light (anti-)nuclei $d(\bar{d})$, $t(\bar{t})$ and ${}^{3}He$ in relativistic heavy-ion collisions at RHIC and LHC energies. A simultaneous fit is performed with the Blast-Wave (BW) model to the transverse momentum ({\ppt}) spectra of identified hadrons together with light (anti-)nuclei produced in $Au+Au$ collisions at {\sqrtsNN} = 7.7 -- 200 GeV at the RHIC and in $Pb+Pb$ collisions at $\sqrt{{\mathrm{s}}_{{}_{\mathrm{NN}}}}$ = 2.76 TeV at the LHC. The energy and centrality dependence of freeze-out parameters, i.e., kinetic freeze-out temperature ($T_{kin}$) and collective flow velocity $⟨\beta ⟩$ has been studied. It is observed that light (anti-)nuclei also participate in the collective expansion of the medium created in the collision when included in a common fit with the light hadrons. We observe a marginal rise in $T_{kin}$ and a slight decrease in $⟨\beta ⟩$ when compared to the values obtained from the fit to light hadrons. A similar $⟨\beta ⟩$ and significantly larger $T_{kin}$ is observed when a fit is performed to only protons and light (anti-)nuclei. Both, $T_{kin}$ and $⟨\beta ⟩$ show a weak energy dependence at most collision energies.

    ↳ nucl-thhep-phPRC(2024)·4 citations
25. 25*

    Examination of STAR fixed-target data on directed flow at $\sqrt{s_{NN}}=$ 3 and 4.5 GeV

    Yu. B. Ivanov🇷🇺 · M. Kozhevnikova🇷🇺

    We present results of simulations of directed flow of various hadrons in Au+Au collisions at collision energies of $\sqrt{s_{NN}}=$ 3 and 4.5 GeV. Simulations are performed within the model three-fluid dynamics (3FD) and the event simulator based on it (THESEUS). The results are compared with recent STAR data. The directed flows of various particles provide information on dynamics in various parts and at various stages of the colliding system depending on the particle. However, the information on the equation of state is not always directly accessible because of strong influence of the afterburner stage or insufficient equilibration of the matter. It is found that the crossover scenario gives the best overall description of the data. This crossover EoS is soft in the hadronic phase. The transition into QGP in Au+Au collisions occurs at collision energies between 3 and 4.5 GeV, at baryon densities $n_B\ge 4n_0$ and temperatures $\approx 150$ MeV. In-medium effects in the directed flow of (anti)kaons are discussed.

    ↳ nucl-thhep-phnucl-exPRC(2024)·6 citations
26. 26*

    The Future of Primordial Black Holes: Open Questions and Roadmap

    Antonio Riotto🇨🇭 · Joe Silk🇫🇷

    We discuss some of the the open questions and the roadmap in the physics of primordial black holes. Black holes are the only dark matter candidate that is known to actually exit. Their conjectured primordial role is admittedly based on hypothesis rather than fact, most straightforwardly as a simple extension to the standard models of inflation, or even, in homage to quantum physics, more controversially via a slowing-down of Hawking evaporation. Regardless of one's stance on the theoretical basis for their existence, the possibility of primordial black holes playing a novel role in dark matter physics and gravitational wave astronomy opens up a rich astrophysical phenomenology that we lay out in this brief overview.

    ↳ astro-ph.COgr-qchep-ph21 citations
27. 27*

    Fermionic Fixed-Point Structure of Asymptotically Safe QED with a Pauli Term

    Holger Gies🇩🇪 · Kevin K. K. Tam🇩🇪

    We test the physical viability of a recent proposal for an asymptotically safe modification of quantum electrodynamics (QED), whose ultraviolet physics is dominated by a non-perturbative Pauli spin-field coupling. We focus in particular on its compatibility with the absence of dynamical generation of fermion mass in QED. Studying the renormalization group flow of chiral four-fermion operators and their fixed points, we discover a distinct class of behavior compared to the standard picture of fixed-point annihilation at large gauge couplings and the ensuing formation of chiral condensates. Instead, transcritical bifurcations, where the fixed points merely exchange infrared stability, are observed. Provided that non-chiral operators remain irrelevant, our theory accommodates a universality class of light fermions for $N_{\text{f}}>1$ irreducible Dirac flavors. On the contrary, in the special case of $N_{\text{f}}=1$ flavor, this comes only at the expense of introducing one additional relevant parameter.

    ↳ hep-thcond-mat.str-elhep-phEPJC(2024)·3 citations
28. 28*

    Ultralight vector dark matter search using data from the KAGRA O3GK run

    The LIGO Scientific Collaboration · the Virgo Collaboration · the KAGRA Collaboration: A. G. Abac · R. Abbott · H. Abe · I. Abouelfettouh · F. Acernese · K. Ackley · C. Adamcewicz · S. Adhicary · N. Adhikari · R. X. Adhikari and 1790 other authors

    Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for $U(1{)}_{B-L}$ gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the $U(1{)}_{B-L}$ gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM.

    ↳ astro-ph.COgr-qchep-phPRD(2024)·39 citations
29. 29*

    Understanding gravitationally induced decoherence parameters in neutrino oscillations using a microscopic quantum mechanical model

    Alba Domi🇩🇪 · Thomas Eberl🇩🇪 · Max Joseph Fahn🇩🇪 · Kristina Giesel🇩🇪 · Lukas Hennig🇩🇪 · Ulrich Katz🇩🇪 · Roman Kemper🇩🇪 · Michael Kobler🇩🇪

    In this work, a microscopic quantum mechanical model for gravitationally induced decoherence introduced by Blencowe and Xu is investigated in the context of neutrino oscillations. The focus is on the comparison with existing phenomenological models and the physical interpretation of the decoherence parameters in such models. The results show that for neutrino oscillations in vacuum gravitationally induced decoherence can be matched with phenomenological models with decoherence parameters of the form ${\Gamma }_{ij}\sim \Delta m_{ij}^4{E}^{-2}$. When matter effects are included, the decoherence parameters exhibit a dependence on the varying matter density across the Earth layers. This behavior can be explained by the nature of the coupling between neutrinos and the gravitational wave environment, as suggested by linearised gravity. On a theoretical level, these different models can be characterised by a different choice of Lindblad operators, with the model with decoherence parameters that do not include matter effects being less suitable from the point of view of linearised gravity. Consequently, in the case of neutrino oscillations in matter, the microscopic model does not agree with many existing phenomenological models that assume constant decoherence parameters in matter. Nonetheless, we identify the KamLAND experimental setup as particularly well-suited to establish the first experimental constraints on the model parameters, namely the neutrino coupling to the gravitational wave environment and its temperature, based on a prior analysis using the phenomenological model.

    ↳ gr-qchep-phJCAP(2024)·19 citations
30. 30*

    Resonant history of gravitational atoms in black hole binaries

    Giovanni Maria Tomaselli🇳🇱 · Thomas F.M. Spieksma🇩🇰 · Gianfranco Bertone🇳🇱

    Rotating black holes can produce superradiant clouds of ultralight bosons. When the black hole is part of a binary system, its cloud can undergo resonances and ionization. These processes leave a distinct signature on the gravitational waveform that depends on the cloud's properties. To determine the state of the cloud by the time the system enters the band of future millihertz detectors, we study the chronological sequence of resonances encountered during the inspiral. For the first time, we consistently take into account the nonlinearities induced by the orbital backreaction and we allow the orbit to have generic eccentricity and inclination. We find that the resonance phenomenology exhibits striking new features. Resonances can "start" or "break" above critical thresholds of the parameters, which we compute analytically, and induce dramatic changes in eccentricity and inclination. Applying these results to realistic systems, we find two possible outcomes. If the binary and the cloud are sufficiently close to counter-rotating, the cloud survives in its original state until the system enters in band; otherwise, the cloud is destroyed during a resonance at large separations, but leaves an imprint on the eccentricity and inclination. In both scenarios, we characterize the observational signatures, with particular focus on future gravitational wave detectors.

    ↳ gr-qchep-phhep-thPRD(2024)·63 citations
31. 31*

    Constraining the equation of state in neutron-star cores via the long-ringdown signal

    Christian Ecker🇩🇪 · Tyler Gorda🇩🇪 · Aleksi Kurkela🇳🇴 · Luciano Rezzolla🇩🇪

    Multimessenger signals from binary neutron star (BNS) mergers are promising tools to infer the largely unknown properties of nuclear matter at densities that are presently inaccessible to laboratory experiments. The gravitational waves (GWs) emitted by BNS merger remnants, in particular, have the potential of setting tight constraints on the neutron-star equation of state (EOS) that would complement those coming from the late inspiral, direct mass-radius measurements, or ab-initio dense-matter calculations. To explore this possibility, we perform a representative series of general-relativistic simulations of BNS systems with EOSs carefully constructed so as to cover comprehensively the high-density regime of the EOS space. From these simulations, we identify a novel and tight correlation between the ratio of the energy and angular-momentum losses in the late-time portion of the post-merger signal, i.e., the ``long ringdown'', and the properties of the EOS at the highest pressures and densities in neutron-star cores. When applying this correlation to post-merger GW signals, we find a significant reduction of the EOS uncertainty at densities several times the nuclear saturation density, where no direct constraints are currently available. Hence, the long ringdown has the potential of providing new and stringent constraints on the state of matter in neutron stars in general and, in particular, in their cores.

    ↳ astro-ph.HEgr-qchep-phnucl-thNature Commun.(2025)·32 citations
32. 32*

    QCD critical point and hydrodynamic fluctuations in relativistic fluids

    Mikhail Stephanov🇺🇸

    These lecture notes consist of two major connected parts. The first part (Sections 1, 2), after a brief historical introduction, deals with the physics of critical points in thermodynamic equilibrium. The features of the fluctuations relevant for the QCD critical point search are highlighted. The second part (Sections 3, 4) focuses on the recent developments in the description of the fluctuation dynamics especially relevant for the QCD critical point search in heavy-ion collisions.

    ↳ nucl-thcond-mat.stat-mechhep-phActa Phys.Polon.B(2024)·5 citations
33. 33*

    Impossible Symmetries and Conformal Gravity

    Kurt Hinterbichler🇺🇸 · Austin Joyce🇺🇸 · Grégoire Mathys🇺🇸

    We explore the physics of relativistic gapless phases defined by a mixed anomaly between two generalized conserved currents. The gapless modes can be understood as Goldstone modes arising from the nonlinear realization of (generically higher-form) symmetries arising from these currents. In some cases, the anomaly cannot be reproduced by any local and unitary theory, indicating that the corresponding symmetries are impossible, in the sense that they cannot appear in a Lorentzian physical system. We consider many examples of the general construction. Most notably, we study conformal gravity from this perspective, describing the higher-form symmetries of the linear theory and showing how it can be understood in terms of anomalies. Along the way we clarify some aspects of electric-magnetic duality in linear conformal gravity.

    ↳ hep-thhep-phPRD(2024)·11 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.