Tue·May 7, 2024Tuesday·May 7, 2024

1. 01*

   Lepton-neutron interaction and S-wave low energy parameters

   Jaume Carbonell🇫🇷 · Tobias Frederico🇧🇷

   A lepton-neutron potential in configuration space is obtained. It is based on the Coulomb plus hyperfine interaction Hamiltonian integrated over the neutron charge and magnetic densities. Different parametrisations of the neutron electromagnetic form factors are compared. It is given in the operator form with a central, spin-spin, tensor and spin-orbit terms. The potentials for lowest partial waves states are presented. We compute the lepton-neutron lepton ($ln$) low-energy parameters for the S-waves, estimate the zero-energy cross sections for higher angular momentum states, and point out a possible divergence in the partial wave summation due to the spin-orbit potential.

   hep-phcond-mat.mtrl-scinucl-thphysics.atom-ph+1PRC(2024)·0 citations
2. 02*

   Higgs criticality in and beyond the Standard Model

   Thomas Steingasser🇺🇸

   The properties of the Higgs potential are determined by three parameters: the mass parameter, the quartic self-coupling, and a constant term. Remarkably, all three of these parameters seem subject to a significant amount of fine-tuning. All these tunings can be seen as their corresponding parameters being close to critical values marking quantum phase transitions. While such behavior is surprising from a conventional particle physics perspective, it is a common feature of dynamical systems. This has motivated the conjecture that the values of the Higgs' parameters are the result of some dynamical mechanism. This possibility suggests the construction of mechanisms dynamically choosing sets of Higgs parameters. In these notes, I discuss a complementary approach. Taking seriously that such a mechanism could exist in nature, it is plausible to assume that it also influences Beyond-Standard-Model physics. This suggests considering near-criticality in any model of interest and investigating its consequences more generally, in particular independent of a concrete mechanism responsible for it. I first explain what it means for the parameters of the Higgs potential to be near-critical. This includes a discussion of the recently discovered "metastability bound" on the Higgs mass, which can be understood through a critical point. I then review two concrete examples of mechanisms in which the parameters of the Higgs potential are dynamically driven towards critical values. These mechanisms also serve as an important proof on concept for the feasibility of the assumptions at the foundation of these notes. Using a simple example for concreteness, the final part of these notes then explicitly demonstrates how to approach a given model in the light of the near-criticality conjecture.

   hep-phastro-ph.COhep-thPoS(2024)·12 citations
3. 03*

   Solar Neutrinos in Cryogenic Detectors

   A. Bento🇩🇪 · A. Bertolini🇩🇪 · L. Canonica🇩🇪 · S. Di Lorenzo🇮🇹 · F. Dominsky🇩🇪 · N. Ferreiro Iachellini🇩🇪 · D. Fuchs🇩🇪 · A. Garai🇩🇪 · D. Hauff🇩🇪 · A. Langenkämper🇩🇪 · M. Mancuso🇩🇪 · B. Mauri🇩🇪 and 4 other authors

   Coherent elastic neutrino-nucleus scattering (CE$\nu$NS) poses an irreducible background in the search for dark matter-nucleus elastic scatterings, which is commonly known as the neutrino floor. As direct dark matter search experiments keep improving their sensitivity into so far unexplored regions, they face the challenge of approaching this neutrino floor. A precise description of the CE$\nu$NS signal is therefore crucial for the description of backgrounds for future DM searches. In this work we discuss the scenario of detecting neutrinos in low-threshold, high-exposure cryogenic solid state experiments optimized for the search of low-mass dark matter. The energy range considered is completely dominated by solar neutrinos. In absence of any dark matter events, we treat solar neutrinos as the main signal of interest. We show that sensitivity to the flux of neutrinos from different production mechanisms can be achieved. In particular we investigate the sensitivity to the flux of pp and ${}^7$Be neutrinos, as well as CNO neutrinos. Furthermore, we investigate the sensitivity to dark matter signals in the presence of a solar neutrino background for different experimental scenarios, which are defined by three parameters: the target material, the energy threshold and the exposure. We show that experiments with thresholds of $\mathcal{O}$(eV) and exposures of $\mathcal{O}$(tonne-years), using CaWO${}_4$ or Al${}_2$O${}_3$ targets, have discovery potential for dark matter interaction cross sections in the neutrino floor.

   hep-phastro-ph.COEPJC(2024)·3 citations
4. 04*

   Production of hidden-heavy and double-heavy hadronic molecules at the $Z$ factory of CEPC

   Zhao-Sai Jia🇨🇳 · Gang Li🇨🇳 · Pan-Pan Shi🇪🇸 · Zhen-Hua Zhang🇨🇳

   With a clean environment and high collision energy, the Circular Electron Positron Collider (CEPC) would be an excellent facility for heavy flavor physics. Using the Monte Carlo event generator Pythia, we simulate the production of the charmed (bottom) hadron pairs in the electron-positron collisions at the $Z$ factory of CEPC, and the inclusive production rates for typical candidates of the hidden/double-charm and hidden/double-bottom $S$-wave hadronic molecules are estimated at an order-of-magnitude level with the final state interactions after the hadron pair production. The predicted cross sections for the hidden-charm meson-meson molecules $X(3872)$ and $Z_c(3900)$ are at $\mathrm{pb}$ level, which are about two to three orders of magnitude larger than the production cross sections for the double-charm meson-meson molecules $T_{cc}$ and $T_{cc}^{\ast }$, as the double-charmed ones require the production of two pairs of $c\bar{c}$ from the $Z$ boson decay. The production cross sections for the hidden-charm pentaquark states $P_c$ and $P_{cs}$ as meson-baryon molecules are a few to tens of fb, which are about one magnitude larger than those of the possible hidden-charm baryon-antibaryon and double-charm meson-baryon molecules. In the bottom sector, the production cross sections for the $Z_b$ states as $B^{(\ast )}{\bar{B}}^{\ast }$ molecules are about tens to hundreds of fb, indicating $10^6$ - $10^7$ events from a two-year operation of CEPC, and the expected events from the double-bottom molecules are about 2 - 5 orders of magnitude smaller than the $Z_b$ states. Our results shows great prospects of probing heavy exotic hadrons at CEPC.

   hep-phPRD(2024)·2 citations
5. 05*

   Exploration of the LHCb $P_c$ states and possible resonances in a unitary coupled-channel model

   Chao-Wei Shen🇩🇪 · Deborah Rönchen🇩🇪 · Ulf-G. Meißner🇩🇪 · Bing-Song Zou🇨🇳 · Yu-Fei Wang🇩🇪

   We extend our previous study of the interactions of ${\bar{D}}^{(\ast )}{\Lambda }_c-{\bar{D}}^{(\ast )}{\Sigma }_c^{(\ast )}$ within an analytic, unitary, coupled-channel approach by including the $J/\psi p$ channel and performing fits to the $J/\psi p$ invariant mass distributions in the ${\Lambda }_b^0\to J/\psi p{K}^{-}$ decay by the LHCb Collaboration. We take into account the contributions of $t$-channel pseudoscalar and vector meson exchanges and $u$-channel baryon exchanges in this work, and a series of bound states and resonances with different spin-parities are dynamically generated. According to the results, four states have a significant impact on the physical observables, with two having a spin-parity of $1/2^{-}$ and the other two having $3/2^{-}$. These states can be associated with the LHCb hidden-charm pentaquarks. We further provide the coupling strength between each pole and different channels, which provides some insights on how to search for them in future experiments. Moreover, we also search for poles in higher partial waves up to $J=7/2$ and find indications for the existence of several states with larger widths.

   hep-phEPJC(2024)·11 citations
6. 06*

   Composite effective field theory signal from anomalous quartic gauge couplings for $ZZ(\to \ell \ell \nu \nu )jj$ and $Z\gamma (\to \nu \nu \gamma )jj$ productions

   Artur E. Semushin🇷🇺 · Evgeny Yu. Soldatov🇷🇺

   Parameterization of heavy effects beyond the Standard Model is available using higher-dimension operators of the effective field theory and their Wilson coefficients, where their values are not known. Experimental sensitivity to the Wilson coefficients can be significantly changed in case of the usage of composite anomalous signal, which contains anomalous contributions from background processes in addition to the conventional ones from the signal process. In this work, this approach is applied to the search for anomalous quartic gauge couplings with seven EFT operators in the electroweak production of $ZZ(\to \ell \ell \nu \nu )jj$ and $Z\gamma (\to \nu \nu \gamma )jj$ in $pp$ collisions. For the majority of coefficients sensitivity in the former channel is smaller than that in the latter one. However, it is shown that composite anomalous signal affects $ZZ(\to \ell \ell \nu \nu )jj$ production stronger than $Z\gamma (\to \nu \nu \gamma )jj$ production, making sensitivities closer. One-dimensional limits on the Wilson coefficients are changed up to 27.3% and 9.7% due to the background anomalous contributions in $ZZ(\to \ell \ell \nu \nu )jj$ and $Z\gamma (\to \nu \nu \gamma )jj$ productions respectively.

   hep-phhep-exLHEP(2024)·1 citation
7. 07*

   Production of meson molecules in ultra-peripheral heavy ion collisons

   F.C. Sobrinho🇧🇷 · L.M. Abreu🇧🇷 · C.A. Bertulani🇺🇸 · F.S. Navarra🇧🇷

   In this work we present a calculation of exotic charmonium production in ultra-peripheral collisions, in which the exotic state is explicitly treated as a meson molecule. Our formalism is general but we focus on the lightest possible exotic charmonium state: a $D^{+}{D}^{-}$ molecular bound state. It was proposed some time ago and it has been object of experimental searches. Here we study the production of the open charm pair in the process $\gamma \gamma \to D^{+}{D}^{-}$. Then we use a prescription to project the free pair $|D^{+}{D}^{-}⟩$ onto a bound state at the amplitude level and compute the cross section of the process $\gamma \gamma \to B$ (where $B$ is the bound state). Finally, we convolute this last cross section with the equivalent photon distributions coming from the projectile and target in an ultra-peripheral collision and find the $AA\to AAB$ cross section, which, for $Pb-Pb$ collisions at $\sqrt{s_{NN}}=5.02$ TeV, is of the order of $3\mu \text{mbox}b$.

   hep-phPRD(2024)·7 citations
8. 08*

   Composite effective field theory signal in case of searching for neutral triple gauge couplings with $ZZ\to \ell \ell \nu \nu$ production

   Artur E. Semushin🇷🇺 · Evgeny Yu. Soldatov🇷🇺

   In this work manifestations of physics beyond the Standard Model are parameterized with higher-dimension operators and Wilson coefficients using effective field theory. In order to set more stringent experimental limits on the Wilson coefficients it is crucial to use new methods of sensitivity increasing that work independently with luminosity growth. Method of composite anomalous signal allows one to set the limits on Wilson coefficients more precisely and stringent by accounting for impact of EFT operators on background processes in addition to the conventional anomalous contribution from the signal process. This work presents aforementioned methodology applied to the $ZZ\to \ell \ell \nu \nu$ production, that is sensitive to the neutral triple couplings of gauge bosons $Z$ and $\gamma$. It is found that the main background BSM contribution comes from $WZ\to \ell \nu \ell \ell$ background. Improvement of the limits on the Wilson coefficients due to this background depends on the coefficient and is up to 57.5% (59.1%) for one- (two-) dimensional limits in linear + quadratic effective field theory model and up to 94.4% for one-dimensional limits in linear effective field theory model.

   hep-phhep-exPhys.Atom.Nucl.(2024)·0 citations
9. 09*

   Prospect study for measurement of $Hb\bar{b}$ coupling at the LHC and FCC-hh

   Zahra Abdy🇵🇱 · Mojtaba Mohammadi Najafabadi🇮🇷

   This paper employs the $H+b+\text{jets}$ signature in proton-proton collisions to explore the structure of the $Hb\bar{b}$ couplings.The focus of the analysis lies in the decay of the Higgs boson into a photon pair, taking into account both reducible and irreducible backgrounds and a realistic simulation of the detector effects. To enhance the discrimination between signal and background, a multivariate analysis is employed to analyse the kinematic variables and optimise the signal-to-background ratio. The results indicate that the $H+b+\text{jets}$ process can significantly contribute to the precise measurement of CP-even and CP-odd couplings between the bottom quark and the Higgs boson at the LHC and FCC-hh. Finally, a novel asymmetry is introduced for the purpose of probing CP violation within the $Hb\bar{b}$ coupling, formulated exclusively based on lab-frame momenta.

   hep-phPRD(2024)·1 citation
10. 10*

    Consequences of the $\mu$-$\tau$ reflection symmetry for leptogenesis in a seesaw model with diagonal Dirac neutrino mass matrix

    Zhen-hua Zhao🇨🇳 · Yan Shao🇨🇳 · Hong-Yu Shi🇨🇳

    In this paper, we have studied the consequences of the $\mu$-$\tau$ reflection symmetry for leptogenesis in the type-I seesaw model with diagonal Dirac neutrino mass matrix. We have first obtained the phenomenologically allowed values of the model parameters, which show that there may exist zero or equal entries in the Majorana mass matrix for the right-handed neutrinos, and then studied their predictions for three right-handed neutrino masses, which show that there may exist two nearly degenerate right-handed neutrinos. Then, we have studied the consequences of the model for leptogenesis. Due to the $\mu$-$\tau$ reflection symmetry, leptogenesis can only work in the two-flavor regime. Furthermore, leptogenesis cannot work for the particular case of $r=1$. Accordingly, for some benchmark values of $r\ne 1$, we have given the constraints of leptogenesis for relevant parameters. Furthermore, we have investigated the possibilities of leptogenesis being induced by the renormalization group evolution effects for two particular scenarios. For the particular case of $r=1$, the renormalization group evolution effects will break the orthogonality relations among different columns of $M_{\mathrm{D}}^{}$ and consequently induce leptogenesis to work. For the low-scale resonant leptogenesis scenario which is realized for nearly degenerate right-handed neutrinos, the renormalization group evolution effects can break the $\mu$-$\tau$ reflection symmetry and consequently induce leptogenesis to work.

    hep-phPRD(2024)·2 citations
11. 11*

    Authentic Majorana versus singlet Dirac neutrino contributions to ${\mu }^{+}{\mu }^{+}\to {\ell }^{+}{\ell }^{+}$ $(\ell =e,\tau )$ transitions

    Jorge Luis Gutiérrez Santiago🇲🇽 · G. Hernández-Tomé🇲🇽 · Diego Portillo-Sánchez🇲🇽 · Javier Rendón🇲🇽

    We revisited the computation of the cross section for the ${\mu }^{+}{\mu }^{+}\to {\ell }^{+}{\ell }^{+}$ $({\ell }^{+}={\tau }^{+},e^{+})$ transitions in the presence of new heavy Majorana neutrinos. We focus on scenarios where the masses of the new states are around some few TeV, the so-called low-scale seesaw models. Our analysis is set in a simple model with only two new heavy Majorana neutrinos considering the current limits on the heavy-light mixings. Our results illustrate the difference between the genuine effects of two nondegenerate heavy Majorana states and the degenerate case where they form a Dirac singlet field.

    hep-phPRD(2024)·7 citations
12. 12*

    Dijet invariant mass distribution near threshold

    Chul Kim🇰🇷 · Taehyun Kwon🇰🇷

    In this paper, using soft-collinear effective theory we study the invariant mass distribution for dijet production in $e^{+}{e}^{-}$-annihilation. Near threshold, where the dijet takes most of the energy, there arise the large threshold logarithms, which are sensitive to soft gluon radiations. To systematically resum the logarithms, we factorize the scattering cross section into the hard, the collinear, and the soft parts. And we additionally factorize the original soft part into the global soft function and the two collinear-soft functions, where the latter can be combined with the collinear parts to form the fragmentation functions to jet (FFJs). The factorization theorem derived here can be easily applicable to other processes near threshold. Using the factorized result, we show the resummed result for the dijet invariant mass to the accuracy of next-to-leading logarithms. We have also obtained the result in the case of the heavy quark dijet and compared it with the case of the light quark.

    hep-phJ.Korean Phys.Soc.(2024)·0 citations
13. 13*

    HEP ML Lab: An end-to-end framework for applying machine learning into phenomenology studies

    Jing Li🇨🇳 · Hao Sun🇨🇳

    Recent years have seen the development and growth of machine learning in high energy physics. There will be more effort to continue exploring its full potential. To make it easier for researchers to apply existing algorithms and neural networks and to advance the reproducibility of the analysis, we develop the HEP ML Lab (hml), a Python-based, end-to-end framework for phenomenology studies. It covers the complete workflow from event generation to performance evaluation, and provides a consistent style of use for different approaches. We propose an observable naming convention to streamline the data extraction and conversion processes. In the Keras style, we provide the traditional cut-and-count and boosted decision trees together with neural networks. We take the $W^{+}$ tagging as an example and evaluate all built-in approaches with the metrics of significance and background rejection. With its modular design, HEP ML Lab is easy to extend and customize, and can be used as a tool for both beginners and experienced researchers.

    hep-phCPC(2025)·2 citations
14. 14*

    Superposition of CP-Even and CP-Odd Higgs Resonances: Explaining the 95 GeV Excesses within a Two-Higgs Doublet Model

    Rachid Benbrik (1)🇲🇦 · Mohammed Boukidi (1)🇲🇦 · Stefano Moretti (2) (3) ((1) Polydisciplinary Faculty, Laboratory of Fundamental and Applied Physics, Cadi Ayyad University, Sidi Bouzid, Safi, Morocco, (2) School of Physics and Astronomy, University of Southampton, United Kingdom, (3) Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden)🇬🇧

    We propose an explanation for the observed excesses around 95 GeV in the di-photon and di-tau invariant mass distributions, as reported by the CMS collaboration at the Large Hadron Collider (LHC). These findings are complemented by a long-standing discrepancy in the $b\bar{b}$ invariant mass at the Large Electron-Positron (LEP) Collider. Additionally, the ATLAS collaboration has reported a corroborative excess in the di-photon final state within the same mass range, albeit with slightly lower significance. Our approach involves the superposition of CP-even and CP-odd Higgs bosons within the Type-III Two-Higgs Doublet Model (2HDM) to simultaneously explain these excesses at 1$\sigma$ Confidence Level (C.L.), while remaining consistent with current theoretical and experimental constraints.

    hep-phPRD(2024)·30 citations
15. 15*

    Longitudinal Momentum Spectra of pair created in a pulsed field at finite times: Are Oscillations "Real"

    Deepak Sah🇮🇳 · Manoranjan P. Singh🇮🇳

    We discuss the mechanism of production of electron-positron pairs from the vacuum in a time-varying, spatially uniform pulsed electric field. We analytically compute the probability of $(e^{+}{e}^{-})$pair production in momentum space using the exact solution of the one-particle time-dependent Dirac equation and compare the result with quantum kinetic theory (QKT). Both approaches allow us to study the particle momentum spectrum at any instant in time and can potentially unveil valuable information regarding quantum non-equilibrium physics. We analyze both approaches' momentum spectra of the created particles at any instant. We observe a multi-profile structure in the LMS. This multi-profile structure clearly illustrates the quantum interference effects associated with pair production. It is worth noting that both approaches exhibit quantum interference patterns at finite times, manifested as oscillations observed in the LMS. We highlight that this quantum signature is a universal behavior seen in the momentum spectra at finite times, where the electric field is nearly zero.

    hep-phquant-ph0 citations
16. 16*

    Quantum Corrections to the Decay Law in Flight

    D. F. Ramírez Jiménez🇵🇱 · A. F. Guerrero Parra🇨🇴 · N. G. Kelkar🇨🇴 · M. Nowakowski🇧🇷

    The deviation of the decay law from the exponential is a well known effect of quantum mechanics. Here we analyze the relativistic survival probabilities, $S(t,p)$, where $p$ is the momentum of the decaying particle and provide analytical expressions for $S(t,p)$ in the exponential (E) as well as the nonexponential (NE) regions at small and large times. Under minimal assumptions on the spectral density function, analytical expressions for the critical times of transition from the NE to the E at small times and the E to NE at large times are derived. The dependence of the decay law on the relativistic Lorentz factor, $\gamma =1/\sqrt{1-v^2/c^2}$, reveals several interesting features. In the short time regime of the decay law, the critical time, ${\tau }_{st}$, shows a steady increase with $\gamma$, thus implying a larger NE region for particles decaying in flight. Comparing $S(t,p)$ with the well known time dilation formula, $e^{-\Gamma t/\gamma }$, in the exponential region, an expression for the critical $\gamma$ where $S(t,p)$ deviates most from $e^{-\Gamma t/\gamma }$ is presented. This is a purely quantum correction. Under particular conditions on the resonance parameters, there also exists a critical $\gamma$ at large times which decides if the NE region shifts backward or forward in time as compared to that for a particle at rest. All the above analytical results are supported by calculations involving realistic decays of hadrons and leptons.

    hep-phAnnals Phys.(2024)·0 citations
17. 17*

    $H\to Z\gamma$ decay and $CP$ violation

    A. I. Hernández-Juárez🇲🇽 · R. Gaitán🇲🇽 · R. Martinez🇨🇴

    This study examines the impact of $CP$-violation on the signal strength ${\mu }^{Z\gamma }$, which was reported as $2.2\pm 0.7$ by the LHC. We obtain constraints on the real and absorptive parts of the $CP$-violating form factor $h_3^{Z\gamma }$ and find that they are less than 1.15 GeV. Additionally, we revisit the leading order Standard Model contributions to the $H\to Z\gamma$ decay and calculate contributions to $h_3^{Z\gamma }$ from FCNC complex couplings mediated by the $Z$ and $H$ bosons. By using the current bounds on such couplings, we find that the FCNC contribution to $h_3^{Z\gamma }$ with top and charm quarks in the loop is of order $10^{-5}$ GeV. While in a model with new quarks that preserves the SM predictions on Higgs decays, the $CP$-violating form factor $h_3^{Z\gamma }$ can be of order $10^{-1}$ GeV and could explain the excess on the signal strength ${\mu }^{Z\gamma }$.

    hep-phPRD(2025)·12 citations
18. 18*

    When The Standard Model Higgs Meets Its Lighter 95 GeV Twin

    Abdesslam Arhrib🇲🇦 · Khiem Hong Phan🇻🇳 · Van Que Tran🇨🇳 · Tzu-Chiang Yuan🇹🇼

    Recent reports from the Large Hadron Collider indicate two excesses: one in the lighter Higgs mass region around 95 GeV, and another in the rare $Z\gamma$ final state of the Standard Model (SM) 125 GeV Higgs decay. These anomalies are analyzed within the minimal gauged two-Higgs-doublet model (G2HDM). A viable parameter space in G2HDM is identified that can account for both excesses. Within the viable parameter space, we find a strong correlation between the signal strengths of the SM 125 GeV Higgs decays into $\gamma \gamma$ and $Z\gamma$ modes. However, this correlation does not extend to the lighter 95 GeV Higgs.

    hep-phNPB(2025)·24 citations
19. 19*

    Beam energy dependence of transverse momentum distribution and elliptic flow in Au-Au collisions using HYDJET++ model

    Satya Ranjan Nayak🇮🇳 · Saraswati Pandey🇮🇳 · B. K. Singh🇮🇳

    In this work, we present the particle ratios, transverse momentum spectra, and elliptic flow ($v_2$) of ${\pi }^{\pm },k^{\pm },$ $p$, and $\bar{p}$ in Au-Au collisions at $\sqrt{s_{NN}}=$ 62.4, 39.0, 27.0, 19.6 and 11.5 GeV using HYDJET++ model. The particle ratios match the experimental data that validates the Cleymans-Reidlich parameterization of freeze-out parameters at lower beam energies under the HYDJET++ framework. The lower collision energies produce a system of high baryon chemical potential (${\mu }_B$) and have a lower inelastic cross section. The interplay between these effects affects the overall shape of the $p_T$ spectra. The HYDJET++ model calculations for $p_T$ spectra agree well with the available experimental data. The invariant yield ratio of central and peripheral collisions is independent of beam energy. The elliptic flow is calculated based on the scaling between initial and final azimuthal spatial anisotropy ($k$). This interpretation of $v_2$ successfully describes the experimental data for all the collision energies studied in this work. The positive correlation of $k$ with beam energy leads to a small $v_2$ at lower collision energies. The hadrons containing strange quarks tend to have smaller values of $k$ than the non-strange hadrons.

    hep-phEur.Phys.J.Plus(2025)·6 citations
20. 20*

    Probing flavor violation and baryogenesis via primordial gravitational waves

    Zafri A. Borboruah🇮🇳 · Anish Ghoshal🇵🇱 · Seyda Ipek🇨🇦

    We show that observations of primordial gravitational waves of inflationary origin can shed light into the scale of flavor violation in a flavon model which also explains the mass hierarchy of fermions. The energy density stored in oscillations of the flavon field around the minimum of its potential redshifts as matter and is expected to dominate over radiation in the early universe. At the same time, the evolution of primordial gravitational waves acts as bookkeeping to understand the expansion history of the universe. Importantly, the gravitational wave spectrum is different if there is an early flavon dominated era compared to radiation domination expected from a standard cosmological model and this spectrum gets damped by the entropy released in flavon decays, determined by the mass of the flavon field $m_S$ and new scale of flavor violation ${\Lambda }_{\mathrm{FV}}$. We derive analytical expressions of the frequency above which the spectrum is damped, as-well-as the amount of damping, in terms of $m_S$ and ${\Lambda }_{\mathrm{FV}}$. We show that the damping of the gravitational wave spectrum would be detectable at BBO, DECIGO, U-DECIGO, $\mu -$ARES, LISA, CE and ET detectors for ${\Lambda }_{\mathrm{FV}}=10^{5-10}$ GeV and $m_S=\mathcal{O}(\mathrm{TeV})$. Furthermore, the flavon decays can source the baryon asymmetry of the universe. We identify the $m_S-{\Lambda }_{\mathrm{FV}}$ parameter space where the observed baryon asymmetry $\eta \sim 10^{-10}$ is produced and can be tested by gravitational wave detectors like LISA and ET. We also discuss our results in the context of the recently measured stochastic gravitational background signals by NANOGrav.

    hep-phastro-ph.COgr-qcJHEP(2024)·11 citations
21. 21*

    Generalized thermodynamic relations for perfect spin hydrodynamics

    Wojciech Florkowski🇵🇱 · Mykhailo Hontarenko🇵🇱

    Generalized thermodynamic relations are introduced into the framework of a relativistic perfect spin hydrodynamics. They allow for consistent treatment of spin degrees of freedom, including the use of spin tensors whose structure follows from microscopic calculations. The obtained results are important for establishing consistency between different formulations of spin hydrodynamics and form the basis for introducing dissipative corrections.

    hep-phnucl-thPRL(2025)·30 citations
22. 22*

    Ladder top-quark condensation imprints in supercooled electroweak phase transition

    Yuepeng Guan🇨🇳 · Shinya Matsuzaki🇨🇳

    The electroweak (EW) phase transition in the early Universe might be supercooled due to the presence of the classical scale invariance involving Beyond the Standard Model (BSM) sectors and the supercooling could persist down till a later epoch around which the QCD chiral phase transition is supposed to take place. Since this supercooling period keeps masslessness for all the six SM quarks, it has simply been argued that the QCD phase transition is the first order, and so is the EW one. However, not only the QCD coupling but also the top Yukawa and the Higgs quartic couplings get strong at around the QCD scale due to the renormalization group running, hence this scenario is potentially subject to a rigorous nonperturbative analysis. In this work, we employ the ladder Schwinger-Dyson (LSD) analysis based on the Cornwall-Jackiw-Tomboulis formalism at the two-loop level in such a gauge-Higgs-Yukawa system. We show that the chiral broken QCD vacuum emerges with the nonperturbative top condensate and the lightness of all six quarks is guaranteed due to the accidental U(1) axial symmetry presented in the top-Higgs sector. We employ a quark-meson model-like description in the mean field approximation to address the impact on the EW phase transition arising due to the top quark condensation at the QCD phase transition epoch. In the model, the LSD results are encoded to constrain the model parameter space. We then observe the cosmological phase transition of the first-order type and discuss the induced gravitational wave (GW) productions. We find that in addition to the conventional GW signals sourced from an expected BSM at around or over the TeV scale, the dynamical topponium-Higgs system can yield another power spectrum sensitive to the BBO, LISA, and DECIGO, etc.

    hep-phJHEP(2024)·9 citations
23. 23*

    Study of quantum decoherence at Protvino to ORCA experiment

    Chinmay Bera🇮🇳 · K. N. Deepthi🇮🇳

    Protvino to ORCA (Oscillation Research with Cosmics in the Abyss) (P2O) is an upcoming neutrino oscillation experiment with a very long baseline of 2595 km. Due to the substantial baseline, this experiment provides a unique opportunity to study the earth matter effects over very large distances. This makes it a suitable experiment to investigate the environmental decoherence in neutrino oscillations, where the neutrino system could interact with a stochastic environment and lead to a loss in the coherence of neutrino states. In this work, we consider an open quantum system framework to simulate the neutrino oscillations in P2O experiment and obtain bounds on the decoherence parameters in different phenomenological models. We assume that the decoherence parameter $\Gamma$ depends on neutrino energy $E_{\nu }$ as ${\Gamma }_{ij}(E_{\nu })={\Gamma }_0(\frac{E_{\nu }}{E_0}{)}^n$. Further, we use these bounds to study the effect on the neutrino mass ordering sensitivity and CP violation sensitivity of P2O experiment.

    hep-phPRD(2024)·7 citations
24. 24*

    Numerical optimization of quantum vacuum signals

    Maksim Valialshchikov🇩🇪 · Felix Karbstein🇩🇪 · Daniel Seipt🇩🇪 · Matt Zepf🇩🇪

    The identification of prospective scenarios for observing quantum vacuum signals in high-intensity laser experiments requires both accurate theoretical predictions and the exploration of high-dimensional parameter spaces. Numerical simulations address the first requirement, while optimization provides an efficient solution for the second one. In the present work, we demonstrate the potential of Bayesian optimization in maximizing photonic quantum vacuum signals on the example of two-beam collisions. This allows us to find the optimal waist sizes for beams with elliptic cross sections, and to identify the specific physical process leading to a discernible signal in a coherent harmonic focusing configuration scenario.

    hep-phphysics.opticsPRD(2024)·3 citations
25. 25*

    Dark matter models with suppressed dark matter nuclei elastic cross section

    N.V.Krasnikov🇷🇺

    We propose two generalizations of the dark photon model which predict the suppressed elastic dark matter nuclei cross section in comparison with the corresponding prediction of the dark photon model. In the first model the main difference from dark photon model is that the mixing parameter $ϵ$ is nonlocal formfactor $ϵ(q^2)=\frac{q^2}{{\Lambda }^2}V(\frac{q^2}{{\Lambda }^2})$ depending on the square of the momentum transfer $q^2$. Here $V(\frac{q^2}{{\Lambda }^2})$ is an entire function of the growth $\rho \ge \frac{1}{2}$ and $\Lambda$ is nonlocal scale. In this model our world and dark world are described by renormalizable field theories while the communication between them is performed by nonlocal interaction. The second model is renormalizable model where besides dark photon field $A^{\prime }$ additional vector boson $Z^{\prime }$ interacts with $B-L$ current. The communication between our world and dark world is performed due to nonzero kinetic mixing between $Z^{\prime }$ and $A^{\prime }$ fields. The predictions of the models for the search for dark matter at the accelerators don't contain additional suppression factors.

    hep-phPLB(2024)·2 citations
26. 26*

    Collision geometry in UPC dijet production

    Kari J. Eskola🇫🇮 · Vadim Guzey🇫🇮 · Ilkka Helenius🇫🇮 · Petja Paakkinen🇫🇮 · Hannu Paukkunen🇫🇮

    We present a comprehensive NLO pQCD study on inclusive dijet photoproduction in ultraperipheral nucleus-nucleus collisions (UPCs). Our analysis takes into account the finite size of both the photon-emitting and the target nucleus, estimated using the Wood-Saxon nuclear density profile. We show that a significant part of the measured dijets at large $z_{\gamma }$ in UPC Pb+Pb collisions at 5.02 TeV come from events with relatively small impact parameters of the order of a few nuclear radii, and the cross section predictions thus become sensitive to the modelling of the collision geometry and photon flux near the source nucleus. In addition, we include the modelling of electromagnetic breakup survival factor needed for a direct comparison with the experimental data and study the resolution power of this process in terms of the impact-parameter dependent nuclear parton distribution functions.

    hep-phPhys.Proc.UPC(2024)·1 citation
27. 27*

    Consistent Electroweak Phenomenology of a Nearly Degenerate $Z^{\prime }$ Boson

    Prisco Lo Chiatto🇩🇪 · Felix Yu🇩🇪

    Extracting constraints on kinetic mixing between a new $U(1{)}^{\prime }$ gauge boson hiding under the Standard Model $Z$ boson resonance requires the formalism of non-Hermitian two-point correlation functions at 1-loop order. We derive self-consistent collider constraints on $Z^{\prime }$ bosons with kinetic mixing in a narrow mass window around the $Z$ boson, considering both model-independent and model-dependent bounds. Our treatment elucidates the importance of both avoided level crossing and width suppression due to the quantum Zeno effect in interpreting the existing constraints. We also discuss the implications for future measurements on the $Z$-pole.

    hep-phPRD(2025)·14 citations
28. 28*

    Higher-order NLO initial state QED radiative corrections to $e^{+}{e}^{-}$ annihilation revisited

    A.B. Arbuzov🇷🇺 · U.E. Voznaya🇷🇺

    Radiative corrections due to initial state radiation in electron-positron annihilation are calculated within the QED structure function approach. Results are shown in the next-to-leading logarithmic approximation up to $O({\alpha }^4{L}^3)$ order, where $L=\ln (s/m_e^2)$ is the large logarithm. Several mistakes in previous calculations are corrected. The results are relevant for future high-precision experiments at $e^{+}{e}^{-}$ colliders.

    hep-phPRD(2024)·8 citations
29. 29*

    Next-to-leading-order electroweak correction to $H\to Z^0\gamma$

    Wen-Long Sang🇨🇳 · Feng Feng🇨🇳 · Yu Jia🇨🇳

    Inspired by the recent observation of the Higgs boson radiative decay into $Z^0$ by {\tt ATLAS} and {\tt CMS} Collaborations, we investigate the next-to-leading-order (NLO) electroweak correction to this rare decay process in Standard Model (SM). Implementing the on-shell renormalization scheme, we find that the magnitude of the NLO electroweak correction may reach $7\%$ of the leading order (LO) prediction, much more significant than that of the NLO QCD correction, which is merely about $0.3\%$. After incorporating the $\mathcal{O}(\alpha )$ correction, the predicted partial width from various $\alpha$ schemes tend to converge to each other. Including both NLO electroweak and QCD corrections, the SM prediction for the branching fraction shifts from the LO value of $(1.40-1.71)\times 10^{-3}$ to $(1.55\pm 0.06)\times 10^{-3}$, considerably lower than the measured value ${\mathcal{B}}_{\exp }[H\to Z^0\gamma ]=(3.4\pm 1.1)\times 10^{-3}$. Resolving this alarming discrepancy clearly calls for further theoretical investigations, and, more importantly, experimental efforts from {\tt HL-LHC} and the prospective Higgs factories such as {\tt CEPC} and {\tt FCC-ee}.

    hep-phPRD(2024)·21 citations
30. 30*

    A Model of the Response of Surface Detectors to Extensive Air Showers Based on Shower Universality

    Maximilian Stadelmaier🇩🇪 · Ralph Engel🇩🇪 · Markus Roth🇩🇪 · David Schmidt🇩🇪 · Darko Veberic🇩🇪

    We present a full model of surface-detector responses to extensive air showers. The model is motivated by the principles of air-shower universality and can be applied to different types of surface detectors. Here we describe a parametrization for both water-Cerenkov detectors and scintillator surface detectors, as for instance employed by the upgraded detector array of the Pierre Auger Observatory. Using surface detector data, the model can be used to reconstruct with reasonable precision shower observables such as the depth of the shower maximum $X_{\text{max}}$ and the number of muons $R_{\mu }$.

    hep-phastro-ph.HEastro-ph.IMhep-exPRD(2024)·12 citations
31. 31*

    Opening a meV mass window for Axion-like particles with a microwave-laser-mixed stimulated resonant photon collider

    Kensuke Homma🇯🇵 · Yuri Kirita🇯🇵 · Takafumi Miyamaru🇯🇵 · Takumi Hasada🇯🇵 · Airi Kodama🇯🇵

    We propose a microwave-laser-mixed three-beam stimulated resonant photon collider, which enables access to axion-like particles in the meV mass range. Collisions between a focused pulse laser beam and a focused microwave pulse beam directly produce axion-like particles (ALPs) and another focused pulse laser beam stimulates their decay. The expected sensitivity in the meV mass range has been evaluated. The result shows that the sensitivity can reach the ALP-photon coupling down to $O(10^{-13})$ GeV${}^{-1}$ with $10^6$ shots if 10 -100 TW class high-intensity lasers are properly combined with a conventional 100 MW class S-band klystron. This proposal paves the way for identifying the nature of ALPs as candidates for dark matter, independent of any cosmological and astrophysical models.

    hep-phhep-exPRD(2024)·4 citations
32. 32*

    $D^0$ meson production in $pp$ collisions at large $Q_s^2$

    Yuri N. Lima🇧🇷 · André V. Giannini🇧🇷 · Victor P. Goncalves🇧🇷

    The impact of the non-linear effects in the QCD dynamics on the observables is directly related to the magnitude of the saturation scale $Q_s$, which is predicted to increase with the energy, rapidity and multiplicity. In this paper, we investigate the $D^0$ meson production in $pp$ collisions at forward rapidities and/or high multiplicities considering the Color Glass Condensate (CGC) formalism and the solutions of the running coupling Balitsky - Kovchegov (BK) equation. The contributions of gluon - and charm - initiated processes are taken into account, and a comparison with the current LHCb data is performed. The impact of an intrinsic charm component in the proton's wave function is also estimated. Predictions for the self-normalized yields of $D^0$ mesons as a function of the multiplicity of coproduced charged hadrons are presented, considering $pp$ collisions at $\sqrt{s}=13$ TeV and different values of the meson rapidity. A comparison with the predictions for the kaon and isolated photon production is performed. Our results indicate that a future experimental analysis of the $D^0$ meson production at forward rapidities and high multiplicities can be useful to probe the CGC formalism and to disentangle the contribution of initial - and final - state effects.

    hep-phhep-exPRD(2024)·5 citations
33. 33*

    Searching for the two poles of the $\Xi (1820)$ in the $\psi (3686)\to {\bar{\Xi }}^{+}{\bar{K}}^0{\Sigma }^{\ast -}({\pi }^{-}\Lambda )$ decay

    Man-Yu Duan🇨🇳 · Jing Song🇨🇳 · Wei-Hong Liang🇨🇳 · E. Oset🇪🇸

    We propose the reaction $\psi (3686)\to {\bar{\Xi }}^{+}{\bar{K}}^0{\Sigma }^{\ast -}$, with the ${\Sigma }^{\ast -}$ decaying to ${\pi }^{-}\Lambda$ in order to show evidence for the existence of two $\Xi (1820)$ states, one around $1824$ MeV and narrow, and another one around $1875$ MeV and wide. The phase space for ${\bar{K}}^0{\Sigma }^{\ast -}$ production reduces the effect of the lower mass resonance, magnifying the effect of the higher mass resonance that shows clearly over the phase space. The estimated rate of the production is bigger than the one of the $\psi (3686)\to {\bar{\Xi }}^{+}{K}^{-}\Lambda$ reaction, where a clear peak for $\Xi (1820)$ was observed by the BESIII collaboration, what makes the Beijing facility ideal to carry out the reaction proposed.

    hep-phhep-thEPJC(2024)·6 citations
34. 34*

    Probing SUSY at Gravitational Wave Observatories

    Stefan Antusch🇨🇭 · Kevin Hinze🇨🇭 · Shaikh Saad🇨🇭 · Jonathan Steiner🇩🇪

    Under the assumption that the recent pulsar timing array evidence for a stochastic gravitational wave (GW) background at nanohertz frequencies is generated by metastable cosmic strings, we analyze the potential of present and future GW observatories for probing the change of particle degrees of freedom caused, e.g., by a supersymmetric (SUSY) extension of the Standard Model (SM). We find that signs of the characteristic doubling of degrees of freedom predicted by SUSY could be detected at Einstein Telescope and Cosmic Explorer even if the masses of the SUSY partner particles are as high as about $10^4$ TeV, far above the reach of any currently envisioned particle collider. We also discuss the detection prospects for the case that some entropy production, e.g. from a late decaying modulus field inducing a temporary matter domination phase in the evolution of the universe, somewhat dilutes the GW spectrum, delaying discovery of the stochastic GW background at LIGO-Virgo-KAGRA. In our analysis we focus on SUSY, but any theory beyond the SM predicting a significant increase of particle degrees of freedom could be probed this way.

    hep-phastro-ph.COhep-thPLB(2024)·14 citations
35. 35*

    Dark Matter from Anomaly Cancellation at the LHC

    Jon Butterworth🇬🇧 · Hridoy Debnath🇺🇸 · Pavel Fileviez Perez🇺🇸 · Yoran Yeh🇬🇧

    We discuss a class of theories that predict a fermionic dark matter candidate from gauge anomaly cancellation. As an explicit example, we study the predictions in theories where the global symmetry associated with baryon number is promoted to a local gauge symmetry. In this context the symmetry-breaking scale has to be below the multi-TeV scale in order to be in agreement with the cosmological constraints on the dark matter relic density. The new physical "Cucuyo" Higgs boson in the theory has very interesting properties, decaying mainly into two photons in the low mass region, and mainly into dark matter in the intermediate mass region. We study the most important signatures at the Large Hadron Collider, evaluating the experimental bounds. We discuss the correlation between the dark matter relic density, direct detection and collider constraints. We find that these theories are still viable, and are susceptible to being probed in current, and future high-luminosity, running.

    hep-phastro-ph.COhep-exPRD(2024)·13 citations
36. 36*

    Electroweak results in two-photon collisions at the LHC

    Cecile Caillol (on behalf of the ATLAS and CMS Collaborations)🇨🇭

    The LHC is also a high-energy photon collider. The ATLAS and CMS experiments are exploring a wide diphoton energy range with various approaches in heavy-ion and proton collisions to precisely measure quantum electrodynamics processes and constrain the existence of physics beyond the standard model.

    hep-phhep-ex1 citation
37. 37*

    External magnetic field induced paramagnetic squeezing effect in heavy-ion collisions at the LHC

    Ze-Fang Jiang🇨🇳 · Zi-Han Zhang🇨🇳 · Xue-Fei Yuan🇨🇳 · Ben-Wei Zhang🇨🇳

    In non-central heavy-ion collisions, the quark-gluon plasma (QGP) encounters the most intense magnetic field ever produced in nature, with a strength of approximately 10${}^{19-20}$ Gauss. Recent lattice-QCD calculations reveal that the QGP exhibits paramagnetic properties at high temperatures. When an external strong magnetic field is applied, it generates an anisotropic squeezing force density that competes with pressure gradients resulting from the purely QGP geometric expansion. In this study, we employ (3+1)-dimensional ideal hydrodynamics simulations to estimate the paramagnetic squeezing effect of this force density on the anisotropic expansion of QGP in non-central Pb+Pb collisions at the Large Hadron Collider (LHC). We consider both up-to-date magnetic susceptibility and various magnetic field profiles in this work. We find that the impact of rapidly decaying magnetic fields is insignificant, while enduring magnetic fields produce a strong force density that diminishes the momentum anisotropy of the QGP by up to 10% at the intial stage, leaving a visible imprint on the elliptic flow $v_2$ of final charged particles. Our results provide insights into the interplay between magnetic fields and the dynamics of QGP expansion in non-central heavy-ion collisions.

    ↳ nucl-thhep-phPRC(2024)·7 citations
38. 38*

    An emergent cosmological model from running Newton constant

    Aknur Zholdasbek🇰🇿 · Hrishikesh Chakrabarty🇰🇿 · Daniele Malafarina🇰🇿 · Alfio Bonanno🇮🇹

    We propose an emergent cosmological model rooted in the Asymptotically Safe antiscreening behavior of the Newton constant at Planckian energies. Distinguishing itself from prior approaches, our model encapsulates the variable nature of $G$ through a multiplicative coupling within the matter Lagrangian, characterized by a conserved energy-momentum tensor. The universe emerges from a quasi-de Sitter phase, transitioning to standard cosmological evolution post-Planck Era. Our analysis demonstrates the feasibility of constraining the transition scale to nearly classical cosmology using Cosmic Microwave Background (CMB) data and the potential to empirically probe the antiscreening trait of Newton's constant, as predicted by Asymptotic Safety.

    ↳ gr-qcastro-ph.COhep-phPRD(2025)·9 citations
39. 39*

    Extended NJL model for baryonic matter and quark matter

    Cheng-Jun Xia🇨🇳

    By considering baryons as clusters of three quarks, we extend the Nambu-Jona-Lasinio (NJL) model to describe baryonic matter, quark matter, and their transitions in a unified manner, where the Dirac sea and spontaneous chiral symmetry breaking are considered. In particular, a density-dependent structural function ${\alpha }_S$ is introduced to modulate the four(six)-point interaction strengths to reproduce the baryon masses in vacuum and medium. Vector interactions are considered with the exchange of $\omega$ and $\rho$ mesons, where the density-dependent coupling constants are fixed by reproducing nuclear matter properties as well as the $\Lambda$-hyperon potential depth in nuclear medium. As density increases, quarks will emerge as quasi-free particles and coexist with baryons. This phase is interpreted as quarkyonic matter, where quarks are restricted to the lowest energy states in the presence of baryons, i.e., quarks are still confined. Similar to the treatment of $\alpha$ clustering in nuclear medium, a Pauli blocking term is added to baryon masses so that baryons eventually become unbound in the presence of a quark Fermi Sea. Then at large enough densities baryons vanish and a Mott transition takes place, we consider such a transition as deconfinement phase transition. Depending on the strengths of Pauli blocking term and quark-vector meson couplings, both first-order and continues phase transitions are observed for quarkyonic, chiral, and deconfinement phase transitions. The corresponding compact star structures are then investigated and confronted with various astrophysical constraints.

    ↳ nucl-thhep-phPRD(2024)·14 citations
40. 40*

    Silk Damping in Scalar-Induced Gravitational Waves: A Novel Probe for New Physics

    Yan-Heng Yu🇨🇳 · Sai Wang🇨🇳

    Silk damping is well known in the study of cosmic microwave background (CMB) and accounts for suppression of the angular power spectrum of CMB on large angular multipoles. In this Letter, we study the effect of Silk damping on the scalar-induced gravitational waves (SIGWs). Resulting from the dissipation of cosmic fluid, the Silk damping notably suppresses the energy-density spectrum of SIGWs on scales comparable to a diffusion scale at the decoupling time of feebly-interacting particles. The effect offers a novel observable for probing the underlying particle interaction, especially for those mediated by heavy gauge bosons beyond the standard model of particles. We anticipate that pulsar timing arrays are sensitive to gauge bosons with mass $\sim 10^3-10^4\mathrm{GeV}$, while space- and ground-based interferometers to those with mass $\sim 10^7-10^{12}\mathrm{GeV}$, leading to essential complements to on-going and future experiments of high-energy physics.

    ↳ astro-ph.COgr-qchep-phSCPMA(2025)·17 citations
41. 41*

    Thermodynamic stability in relativistic viscous and spin hydrodynamics

    Xiang Ren🇨🇳 · Chen Yang🇨🇳 · Dong-Lin Wang🇨🇳 · Shi Pu🇨🇳

    We have applied thermodynamic stability analysis to derive the stability and causality conditions for conventional relativistic viscous hydrodynamics and spin hydrodynamics. We obtain the thermodynamic stability conditions for second-order relativistic hydrodynamics with shear and bulk viscous tensors, finding them identical to those derived from linear mode analysis. We then derive the thermodynamic stability conditions for minimal causal extended second-order spin hydrodynamics in canonical form, both with and without viscous tensors. Without viscous tensors, the constraints from thermodynamic stability exactly match those from linear mode analysis. In the presence of viscous tensors, the thermodynamic stability imposes more stringent constraints than those obtained from linear mode analysis. Our results suggest that conditions derived from thermodynamic stability analysis can guarantee both causality and stability in linear mode analysis.

    ↳ nucl-thhep-phhep-thPRD(2024)·26 citations
42. 42*

    Updating neutrino mass constraints with Background measurements

    Deng Wang🇪🇸 · Olga Mena🇪🇸 · Eleonora Di Valentino🇬🇧 · Stefano Gariazzo🇮🇹

    Low-redshift probes, such as Baryon Acoustic Oscillations (BAO) and Supernovae Ia luminosity distances, have been shown to be crucial for improving the bounds on the total neutrino mass from cosmological observations, due to their ability to break degeneracies among the different parameters. Here, we expand background observations to include $H(z)$ measurements from cosmic chronometers, distance moduli from Gamma Ray Bursts (GRBs), and angular diameter distances from galaxy clusters. For the very first time, we find neutrino mass limits below the minimal expectations from neutrino oscillation probes, suggesting non-standard neutrino and/or cosmological scenarios. The tightening of the neutrino mass bound is due to the slightly higher value of the Hubble constant $H_0$ preferred by the former three background probes, and also due to the improved errors on $H_0$ and the matter mass-energy density ${\Omega }_{\mathrm{m}}$. All values of $H_0$ are however in agreement at the $1-2\sigma$ level. Interestingly, it is not only the combination of the three background probes that is responsible for the $\sum m_{\nu }<0.06$~eV limits, but also each of them independently. The tightest bound we find here is $\sum m_{\nu }<0.043$~eV at $2\sigma$ after combining Cosmic Microwave Background Planck data with DESI BAO, Supernovae Ia, GRBs, cosmic chronometers, and galaxy clusters, showing a clear tension between neutrino oscillation results and cosmological analyses. In general, removing either one of the two background probes still provides a limit $\sum m_{\nu }\lesssim 0.06$~eV, reassuring the enormous potential of these low-redshift observations in constraining the neutrino mass.

    ↳ astro-ph.COhep-phPRD(2024)·56 citations
43. 43*

    Revisiting the spatially inhomogeneous condensates in the $(1+1)$-dimensional chiral Gross-Neveu model via the bosonic two-point function in the infinite-$N$ limit

    Adrian Koenigstein🇩🇪 · Marc Winstel🇩🇪

    This work shows that the known phase boundary between the phase with chiral symmetry and the phase of spatially inhomogeneous chiral symmetry breaking in the phase diagram of the $(1+1)$-dimensional chiral Gross-Neveu model can be detected from the bosonic two-point function alone and thereby confirms and extends previous results arXiv:hep-th/0008175, arXiv:0807.2571, arXiv:0909.3714, arXiv:1810.03921, arXiv:2203.08503. The analysis is referred to as the stability analysis of the symmetric phase and does not require knowledge about spatial modulations of condensates. We perform this analysis in the infinite-$N$ limit at nonzero temperature and nonzero quark and chiral chemical potentials also inside the inhomogeneous phase. Thereby we observe an interesting relation between the bosonic $1$-particle irreducible two-point vertex function of the chiral Gross-Neveu model and the spinodal line of the Gross-Neveu model.

    ↳ hep-thcond-mat.str-elhep-phJ.Phys.A(2024)·9 citations
44. 44*

    Percolating Cosmic String loops from evaporating primordial black holes

    Ajit M. Srivastava🇮🇳

    The Pulsar timing data from NANOGrav Collaboration has regenerated interest in the possibility of observing stochastic gravitational wave background arising from cosmic strings. In the standard theory, the cosmic string network forms during spontaneous symmetry breaking (SSB) phase transition in the whole universe via the so called Kibble mechanism. This scenario would not be possible, e.g., in models of low energy inflation, where the reheat temperature is much lower than the energy scale of cosmic strings. We point out a very different possibility, where a network of even high energy scale cosmic strings can form when the temperature of the Universe is much lower. We consider local heating of plasma in the early universe by evaporating primordial black holes (PBHs). It is known that for suitable masses of PBHs, their Hawking radiation may re-heat the surrounding plasma to high temperatures, restoring certain symmetries {\it locally} which are broken at the ambient temperature at that stage. Expansion of the hot plasma cools it so that the {\it locally restored symmetry} is spontaneously broken again. If this SSB supports formation of cosmic strings, then string loops will form in this region around the PBH. Further, resulting temperature gradients lead to pressure gradients such that plasma develops radial flow with the string loops getting stretched as they get dragged by the flow. For a finite density of PBHs of suitable masses, one will get local hot spots, each one contributing to expanding cosmic string loops. For suitable PBH density, the loops from different regions may intersect. Intercommutation of strings can then lead to percolation, leading to the possibility of formation of infinite string network, even when the entire universe never goes through the respective SSB phase transition.

    ↳ gr-qcastro-ph.COhep-phhep-thPLB(2024)·3 citations
45. 45*

    Too Hot to Handle: Searching for Inflationary Particle Production in Planck Data

    Oliver H. E. Philcox🇺🇸 · Soubhik Kumar🇺🇸 · J. Colin Hill🇺🇸

    Non-adiabatic production of massive particles is a generic feature of many inflationary mechanisms. If sufficiently massive, these particles can leave features in the cosmic microwave background (CMB) that are not well-captured by traditional correlation function analyses. We consider a scenario in which particle production occurs only in a narrow time-interval during inflation, eventually leading to CMB hot- or coldspots with characteristic shapes and sizes. Searching for such features in CMB data is analogous to searching for late-Universe hot- or coldspots, such as those due to the thermal Sunyaev-Zel'dovich (tSZ) effect. Exploiting this data-analysis parallel, we perform a search for particle-production hotspots in the Planck PR4 temperature dataset, which we implement via a matched-filter analysis. Our pipeline is validated on synthetic observations and found to yield unbiased constraints on sufficiently large hotspots across $\approx 60\%$ of the sky. After removing point sources and tSZ clusters, we find no evidence for new physics and place novel bounds on the coupling between the inflaton and massive particles. These bounds are strongest for larger hotspots, produced early in inflation, whilst sensitivity to smaller hotspots is limited by noise and beam effects. Through such methods we can constrain particles with masses $\mathcal{O}(100)$ times larger than the inflationary Hubble scale, which represents possibly the highest energies ever directly probed with observational data.

    ↳ astro-ph.COgr-qchep-exhep-ph+1PRD(2025)·17 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.