Tue·Oct 10, 2023Tuesday·October 10, 2023

1. 01*

   Decay of the Z' gauge boson with lepton flavor violation

   D. Espinosa-Gomez🇲🇽 · F. Ramirez-Zavaleta🇲🇽 · E. S. Tututi🇲🇽

   The flavor-violating decay of a new neutral massive gauge boson $Z^{\prime }\to \mu e$ is analyzed in the context of extended models, in which this particle emerges. By means of the analysis of the $\mu \to e\gamma$ decay, $\mu -e$ conversion process in nuclei and the $\mu \to e{e}^{+}{e}^{-}$ decay, the strength of the $Z^{\prime }\mu e$ coupling is estimated and used to calculate the branching ratio of the $Z^{\prime }\to \mu e$ decay. This is done for the so-called $Z_S,Z_{LR},Z_{\chi },Z_{\psi }$ and $Z_{\eta }$ bosons. We found that, through the $\mu -e$ conversion process, the most restrictive bound for the coupling is provided by the $Z_{LR}$ boson. Meanwhile, by means of the $\mu \to e{e}^{+}{e}^{-}$ decay, the most restrictive bound for the $Z^{\prime }\mu e$ coupling is provided by the $Z_{\chi }$ boson. However, if we concentrate on the less restrictive prediction for the Br($Z^{\prime }\to \mu e$), this comes from the $Z_{\eta }$ boson and the resulting branching ratio is less than $10^{-4}$. On the other hand, if we consider the most restrictive bound, the branching ratio for the process is below $2\times 10^{-7}$, which results from the $Z_{RL}$ boson, and is obtained through the $\mu -e$ conversion process.

   hep-phEPJC(2023)·3 citations
2. 02*

   Estimating the Uncertainty of Cosmological First Order Phase Transitions with Numerical Simulations of Bubble Nucleation

   Huai-Ke Guo🇨🇳 · Song Li🇨🇳 · Yang Xiao🇨🇳 · Jin Min Yang🇨🇳 · Yang Zhang🇨🇳

   In order to study the validity of analytical formulas used in the calculation of characteristic physical quantities related to vacuum bubbles, we conduct several numerical simulations of bubble kinematics in the context of cosmological first-order phase transitions to determine potentially existing systematic uncertainties. By comparing with the analytical results, we obtain the following observations: (1) The simulated false vacuum fraction will approach the theoretical one with increasing simulated volume. When the side length of the cubic simulation volume becomes larger than 14.5 ${\beta }_{th}^{-1}$ , the simulated results do not change significantly; (2) The theoretical expected total number of bubbles do not agree with the simulated ones, which may be caused by the inconsistent use of the false vacuum fraction formula; (3) The different nucleation rate prefactors do not affect the bubble kinetics much; (4) The lifetime distribution in the sound shell model does not obey an exponential distribution, in such a way as to cause a suppression in the gravitational wave spectra.

   hep-phastro-ph.COPRD(2024)·5 citations
3. 03*

   Mechanical structure of the nucleon and the baryon octet: Twist-2 case

   Ho-Yeon Won🇰🇷 · Hyun-Chul Kim🇰🇷 · June-Young Kim🇺🇸

   We investigate the gravitational form factors (GFFs) of the nucleon and the baryon octet, decomposed into their flavor components, utilizing a pion mean-field approach grounded in the large $N_c$ limit of Quantum Chromodynamics (QCD). Our focus is on the contributions from the twist-2 operators to the flavor-triplet and octet GFFs, and we decompose the mass, angular momentum, and $D$-term form factors of the nucleon into their respective flavors. The strange quark contributions are found to be relatively mild for the mass and angular momentum form factors, while providing significant corrections to the $D$-term form factor. In the course of examining the flavor decomposition of the GFFs, we uncover that the effects of twist-4 operators play a crucial role. While the gluonic contributions are suppressed by the packing fraction of the instanton vacuum in the twist-2 case, contributions from twist-4 operators are of order unity, necessitating its explicit consideration.

   hep-phJHEP(2024)·21 citations
4. 04*

   Superfluidity in neutrino clusters

   Maxim Dvornikov (1 and 2) ((1) IZMIRAN, (2) JINR)🇷🇺

   We study the formation of a superfluid condensate of neutrinos inside a neutrino cluster. The attractive interaction between neutrinos is mediated by a scalar boson which is lighter than a neutrino. We consider the appearance of neutrino bound states consisting of particles with oppositely directed spins. The gap equation for such a system is derived. Based on numerical simulations of the neutrino distribution in a cluster, we find the phase transition temperature and the coherence length inside such a cluster for various parameters of the system. The constraints on the parameters of the Yukawa interaction, resulting in the neutrino superfluidity, are derived. We obtain that the cosmic neutrino background can contribute to the superfluid condensate inside a neutrino cluster having realistic characteristics. The mechanism of the neutrino cluster cooling in the early universe, based on the plasmons Čerenkov radiation, is proposed.

   hep-phcond-mat.supr-conJ.Phys.G(2024)·3 citations
5. 05*

   String-breaking of the triply heavy baryon at finite temperature and chemical potential

   Jia-Jie Jiang🇨🇳 · Xun Chen🇨🇳 · Jiajia Qin🇨🇳 · Miguel Angel Martin Contreras🇨🇳

   In this work, we use gauge/gravity duality to study potential energy and string-breaking of triply heavy baryons at finite temperature and chemical potential. Two different possible configurations of triply heavy baryon are considered. The effect of temperature and chemical potential on string-breaking distance is investigated. With increasing temperature/chemical potential, the sting-breaking distance decreases and then increases in symmetric collinear geometry while steadily increasing in equilateral triangle geometry. Our study provides insights into triply heavy baryon configuration and string-breaking behavior.

   hep-phPRD(2023)·8 citations
6. 06*

   Quantum Gravity Phenomenology and Particle Physics

   Andrea Bevilacqua🇵🇱 · Jerzy Kowalski-Glikman🇵🇱 · Wojciech Wislicki🇵🇱

   Quantum gravity phenomenology has been historically regarded as a difficult endeavour, due to the apparent scarcity of phenomena involving the required scales of length (Planck length $l_P$) and energy (Planck energy $E_P$). It was realized, however, that one can look for cumulative effects of a quantum theory of gravity at energies $E/E_P\ll 1$ if even tiny effects are amplified by the large time of flight or very high energies, common to astrophysical phenomena. In the this work, complementary to the COST action CA18108 White Book, we put forward a proposal that quantum gravity phenomenology can be fruitfully pursued also with the help of terrestrial particles accelerators. We first discuss the theoretical background, and then concentrate on deformed discrete symmetries C,P,T. We investigate possible experimental signatures of CPT deformation, particularly concerning the difference in decay time between particles and antiparticles, and fields interference.

   hep-phhep-th3 citations
7. 07*

   Regge trajectories for the light diquarks

   Jiao-Kai Chen🇨🇳 · Jia-Qi Xie🇨🇳 · Xia Feng🇨🇳 · He Song🇨🇳

   We attempt to present an unified description of the light meson spectra and the light diquark spectra by applying the Regge trajectory approach. However, we find that the direct application of the linear Regge trajectory formula for the light mesons and baryons fails. To address this issue, we fit the experimental data of light meson spectra and the light diquark spectra obtained by other theoretical approaches. By considering the light quark mass and the parameter $C$ in the Cornell potential, we provide a provisional Regge trajectory formula. We also crudely estimate the masses of the light diquarks $(ud)$, $(us)$, and $(ss)$, and find that they agree with other theoretical results. The diquark Regge trajectory not only becomes a new and very simple approach for estimating the spectra of the light diquarks, but also can explicitly show the behavior of the masses with respect to $l$ or $n_r$. Moreover, it is expected that the diquark Regge trajectory can provide a simple method for investigating the $\rho$-mode excitations of baryons, tetraquarks and pentaquarks containing diquarks.

   hep-phEPJC(2023)·13 citations
8. 08*

   Wave function of the sexaquark or compact H-dibaryon

   Glennys R. Farrar🇺🇸 · Nico Wintergerst🇩🇰

   We derive and explicitly display the internal wave function of a color-, flavor- and spin- singlet dibaryon composed of uuddss quarks in a spatially symmetric state, in the approximation of exact SU(3) flavor symmetry. This wavefunction shows that the often-used superposition of Lambda Lambda, N Xi and Sigma Sigma baryons, relevant for di-baryon molecules, accounts for only 1/5 of a spatially symmetric six-quark color-flavor-spin-singlet state, with the remaining 4/5 consisting of products of color-octet baryons. Using the correct wavefunction has important implications for calculations of the mass of the lowest-lying flavor-singlet dibaryon, as we illustrate using the Cornell potential. We also provide a compact representation of the state in terms of creation operators, and comment on the impact of not using the optimal operator in lattice studies of this system.

   hep-phhep-latJHEP(2023)·7 citations
9. 09*

   Féeton ($B-L$ Gauge Boson) Dark Matter for the 511-keV Gamma-Ray Excess and the Prediction of Low-energy Neutrino Flux

   Yu Cheng🇨🇳 · Weikang Lin🇨🇳 · Jie Sheng🇨🇳 · Tsutomu T. Yanagida🇯🇵

   The féeton is the gauge boson of the $U(1{)}_{B-L}$ gauge theory. If the gauge coupling constant is extremely small, it becomes a candidate for dark matter. We show that its decay to a pair of electron and positron explains the observed Galactic 511-keV gamma-ray excess in a consistent manner. This féeton dark matter decays mainly into pairs of neutrino and anti-neutrino. Future low-energy experiments with improved directional capability make it possible to capture those neutrino signals. The seesaw-motivated parameter space predicts a relatively short féeton lifetime comparable to the current cosmological constraint.

   hep-phastro-ph.HECPC(2024)·9 citations
10. 10*

    How much do neutrinos live and weigh?

    Federica Pompa🇪🇸 · Olga Mena🇪🇸

    The next-generation water Cherenkov Hyper-Kamiokande detector will be able to detect thousands of neutrino events from a galactic Supernova explosion via Inverse Beta Decay processes followed by neutron capture on Gadolinium. This superb statistics provides a unique window to set bounds on neutrino properties, as its mass and lifetime. We shall explore the capabilities of such a future detector, constraining the former two properties via the time delay and the flux suppression induced in the Supernovae neutrino time and energy spectra. Special attention will be devoted to the statistically sub-dominant elastic scattering induced events, normally neglected, which can substantially improve the neutrino mass bound via time delays. When allowing for a invisible decaying scenario, the $95\%$C.L. lower bound on $\tau /m$ is almost one order of magnitude better than the one found with SN1987A neutrino events. Simultaneous limits can be set on both $m_{\nu }$ and ${\tau }_{\nu }$, combining the neutrino flux suppression with the time-delay signature: the best constrained lifetime is that of ${\nu }_1$, which has the richest electronic component. We find ${\tau }_{{\nu }_1}\gtrsim 4\times 10^5$s at $95\%$C.L. The tightest $95\%$C.L. bound on the neutrino mass we find is $0.34$eV, which is not only competitive with the tightest neutrino mass limits nowadays, but also comparable to future laboratory direct mass searches. Both mass and lifetime limits are independent on the mass ordering, which makes our results very robust and relevant.

    hep-phastro-ph.HEhep-exEPJC(2024)·10 citations
11. 11*

    Complete determination of $SU(3{)}_F$ amplitudes and strong phase in ${\Lambda }_c^{+}\to {\Xi }^0{K}^{+}$

    Chao-Qiang Geng🇨🇳 · Xiao-Gang He🇨🇳 · Xiang-Nan Jin🇨🇳 · Chia-Wei Liu🇨🇳 · Chang Yang🇨🇳

    The BESIII collaboration has recently reported the first time measurement of the decay asymmetry $\alpha ({\Lambda }_c^{+}\to {\Xi }^0{K}^{+})=0.01\pm 0.16(stat.)\pm 0.03(syst.)$ and also a sizable phase shift of ${\delta }_P-{\delta }_S=-1.55\pm 0.25$ or $1.59\pm 0.25$ between S- and P-wave amplitudes. This implies significant strong phase shifts in the decay amplitudes. The strong phases indicate the existence of rescattering or loop effects, which are challenging to calculate due to non-perturbative effects. By employing the flavor $SU(3{)}_F$ symmetry and applying the Körner-Pati-Woo theorem to reduce the number of parameters, we find that the current data already allow us to obtain, for the first time, model-independent decay amplitudes and their strong phases. The establishment of the existence of sizable strong phases opens a window for future investigations into CP violation. In our fit, a notable discrepancy emerges in the branching ratio of ${\Xi }_c^0\to {\Xi }^{-}{\pi }^{+}$. The direct relationship between $\Gamma ({\Lambda }_c^{+}\to \Lambda e^{+}{\nu }_e)$ and $\Gamma ({\Xi }_c^0\to {\Xi }^{-}{e}^{+}{\nu }_e)$, along with newly discovered $SU(3{)}_F$ relations, collectively suggests an underestimation of $\mathcal{B}({\Xi }_c^0\to {\Xi }^{-}{\pi }^{+})$ in experimental findings.

    hep-phhep-exPRD(2024)·32 citations
12. 12*

    $B$ anomalies in the post $R_{K^{(\ast )}}$ era

    T. Hurth🇩🇪 · F. Mahmoudi🇫🇷 · S. Neshatpour🇫🇷

    We discuss the status of $b\to s{\ell }^{+}{\ell }^{-}$ decays in the post-$R_{K^{(\ast )}}$ era. The recent LHCb update of $R_K$ and $R_{K^{\ast }}$ measurements which are now compatible with the Standard Model, constrain new physics contributions to be lepton flavor universal, allowing only small deviations from this limit. Besides the latest LHCb measurements of $R_K$ and $R_{K^{\ast }}$, we also include the recent CMS measurements of $R_K$ and of the branching ratio of $B^{+}\to K^{+}{\mu }^{+}{\mu }^{-}$. We present a model-independent analysis of the $b\to s{\ell }^{+}{\ell }^{-}$ data and investigate the implications of the different sets of observables. In addition, we consider multi-dimensional fits and discuss the significance of more complex new physics scenarios compared to one- and two-dimensional scenarios.

    hep-phPRD(2023)·62 citations
13. 13*

    Normal mode analysis within a mutilated relaxation time approximation

    Jin Hu🇨🇳

    In this paper, we present a detailed analysis of normal modes based on the Boltzmann equation within the mutilated relaxation time approximation (RTA). Using this linearized effective kinetic description, our analysis encompasses a complete order calculation in wavenumber k, extending the conventional hydrodynamic mode analysis to intermediate and short-wavelength regions. Furthermore, our linear mode analysis can provide a natural classification of kinetic modes into collective modes and non-collective single-particle excitations. In the case of an energy-independent relaxation time, the behavior of hydrodynamic onset transitions is recovered (Romatschke in Eur Phys J C 76:352, 2016). However, for the case with an energy-dependent relaxation time, the distinct classification becomes less clear, as the location of hydrodynamic modes is not well separated from non-hydrodynamic modes.

    hep-phnucl-thEPJC(2025)·4 citations
14. 14*

    $t\bar{t}H$ production in NNLO QCD

    Simone Devoto🇮🇹

    In this contribution we present our recent computation of the NNLO QCD corrections to the production of a Higgs boson associated with a top-antitop quark pair. This process is of great importance since it allows for a direct measurement of the top-quark Yukawa coupling, and the inclusion of NNLO corrections is crucial in order to provide theory predictions with an uncertainty competitive with the projected accuracy of the experimental measurements at the end of the high-luminosity phase of the LHC.

    hep-ph0 citations
15. 15*

    Light Thermal Self-Interacting Dark Matter in the Shadow of Non-Standard Cosmology

    Shu-Yu Ho🇰🇷 · Pyungwon Ko🇰🇷 · Dibyendu Nanda🇰🇷

    In this paper, we construct a viable model for a GeV scale self-interacting dark matter (DM), where the DM was thermally produced in the early universe. Here, a new vector-like fermion with a dark charge under the $U(1{)}_D$ gauge symmetry serves as a secluded WIMP DM and it can dominantly annihilate into the light dark gauge boson and singlet scalar through the dark gauge interaction. Also, the self-interaction of DM is induced by the light dark gauge boson via the same gauge interaction. In addition to these particles, we further introduce two Weyl fermions and a doublet scalar, by which the dark gauge boson produced from s-wave DM annihilations can mostly decay into active neutrinos after the dark symmetry breaking such that the CMB bound on the DM with low masses can be eluded. In order to have a common parameter region to explain the observed relic abundance and self-interaction of DM, we also study this model in a non-standard cosmological evolution, where the cosmic expansion driven by a new field species is faster than the standard radiation-dominated universe during the frozen time of DM. Reversely, one can also use the self-interacting nature of light thermal DM to examine the non-standard cosmological history of the universe.

    hep-phastro-ph.COJCAP(2024)·2 citations
16. 16*

    Migdal effect of Phonon-mediated neutrino nucleus scattering in semiconductor detectors

    Yu-Feng Li🇨🇳 · Shuo-yu Xia🇨🇳

    In this work, we introduce the theoretical framework of the phonon-mediated Migdal effect for neutrino-nucleus scattering in semiconductors, considering both the Standard Model and the presence of the neutrino magnetic moment. We calculate the rate of electron excitation resulting from the Migdal effect and observe a substantial coherent enhancement compared to ordinary neutrino-electron scattering. Furthermore, we provide numerical sensitivities for detecting the Migdal effect and constraints on the neutrino magnetic moment, utilizing an experimental setup with reactor neutrinos.

    hep-phNPB(2024)·6 citations
17. 17*

    Two-loop coefficient functions in deeply virtual Compton scattering: flavor-singlet axial-vector and transversity case

    Yao Ji🇩🇪 · Jakob Schoenleber🇩🇪

    We calculate the two-loop flavor-singlet axial-vector and gluon transversity coefficient functions for deeply virtual Compton scattering in QCD. We observe interesting properties regarding the transcendentality of the transversity coefficient function. Our results complete the calculation of the full next-to-next-to-leading order coefficient function in deeply virtual Compton scattering. Numerically, the two-loop corrections in the axial-vector and transversity channel are comparable to their vector counterpart at moderate skewness parameter {\xi} and hence indispensable for analyzing the upcoming high-precision data from the Electron-Ion Collider.

    hep-phJHEP(2024)·17 citations
18. 18*

    Additional moments and x-space approximations of four-loop splitting functions in QCD

    S. Moch (Hamburg U., Inst. Theor. Phys. II)🇩🇪 · B. Ruijl (ETH, Zurich)🇨🇭 · T. Ueda (Juntendo U.)🇯🇵 · J. Vermaseren (Nikhef, Amsterdam)🇳🇱 · A. Vogt (Liverpool U., Dept. Math.)🇬🇧

    We have extended our previous computations of the even-N moments of the flavour-singlet four-loop splitting functions to N = 12 for the pure-singlet quark case and N = 10 for all other cases. These results, obtained using physical quantities in inclusive deep-inelastic scattering, have been and will be used to validate conceptionally much more challenging determinations of these splitting functions from off-shell operator matrix elements (OMEs). For the quark-gluon and gluon-gluon splitting functions, which have yet to be computed to higher N using OMEs, we construct approximations based on our moments and endpoint constraints, where we present new large-x results for the gluon-gluon case. These approximations facilitate an approximate N^3LO evolution of parton distributions which are sufficiently accurate outside the region of small momentum fractions x.

    hep-phPLB(2024)·56 citations
19. 19*

    A new approach to the 3-momentum regularization of the in-medium one and two fermion line integrals with applications to cross sections in the Nambu--Jona-Lasinio model

    Renan Câmara Pereira🇵🇹 · João Moreira🇵🇹 · Pedro Costa🇵🇹 · Constança Providência🇵🇹

    We propose the 3-momentum sphere intersection regularization applied to the one and two fermion line integrals at finite temperature and chemical potential. The quark-antiquark polarization function in this new regularization approach is equivalent to the usual 3-momentum regularization, when the absolute value of the external 3-momentum of the polarization is zero. Additionally, it respects the particle-antiparticle symmetry of meson states in the Nambu$-$Jona-Lasinio (NJL) model for all values of temperature and chemical potential. Without this symmetry, in-medium cross sections calculated in the 3-momentum regularized NJL model are not consistent. In order to demonstrate the difference between the usual 3-momentum regularization with the one proposed in this work, we study the quark-quark and quark-antiquark cross sections in both regularization schemes. To this end we use the standard $SU(3)$ NJL model, with four and six quark interactions. We observe major quantitative and qualitative differences when comparing quark-quark cross sections in both schemes. The quark-antiquark cross sections, on the other hand, are very similar in both regularizations, owning to the equivalence between the regularizations when the absolute value of the external 3-momentum is zero.

    hep-phnucl-thPRC(2024)·1 citation
20. 20*

    Collective modes of a massive fermion in a magnetized medium with finite anomalous magnetic moment

    Nilanjan Chaudhuri🇮🇳 · Snigdha Ghosh🇮🇳 · Pradip Roy🇮🇳 · Sourav Sarkar🇮🇳

    We calculate, in a systematic way, the general structure of the self-energy of light massive fermions and the effective propagator in a thermomagnetic medium with the inclusion of anomalous magnetic moment (AMM) of the fermion in the weak field approximation. It is found that the self-energy of a massive fermion in this case consists of five non-trivial structure factors in contrast to the massless case where the self-energy contains only four. We employ the real time formalism (RTF) of thermal field theory within the ambit of hard thermal loop (HTL) approximation in the evaluation of the structure factors. The collective modes are obtained from the poles of the effective propagator of the fermion. The investigation of the dispersion relations for non-degenerate ground state shows that the effect of the magnetic field is more for up quark than the down quark because of the larger charge of the former. The important observation is that in the first excited state the degeneracy, which exists for non-zero magnetic field is lifted due to the inclusion of the AMM. It is also observed that the first excited state becomes less dispersive compared to the case when AMM is not considered, whereas the second excited state becomes more dispersive when both the magnetic field and the AMM are non-zero in comparison to the case with vanishing AMM. These effects are observed in both particle and hole-like excitations. Qualitatively similar behaviour is also seen in the case of down quarks.

    hep-phnucl-thPRD(2023)·9 citations
21. 21*

    Triple-collinear splittings with massive particles

    Prasanna K. Dhani🇪🇸 · Germán Rodrigo🇪🇸 · German F. R. Sborlini🇪🇸

    We analyze in detail the most singular behaviour of processes involving triple-collinear splittings with massive particles in the quasi-collinear limit, and present compact expressions for the splitting amplitudes and the corresponding splitting kernels at the squared-amplitude level. Our expressions fully agree with well-known triple-collinear splittings in the massless limit, which are used as a guide to achieve the final expressions. These results are important to quantify dominant mass effects in many observables, and constitute an essential ingredient of current high-precision computational frameworks for collider phenomenology.

    hep-phJHEP(2023)·22 citations
22. 22*

    A Leptonic ALP Portal to the Dark Sector

    Giovanni Armando🇮🇹 · Paolo Panci🇮🇹 · Joachim Weiss🇩🇪 · Robert Ziegler🇩🇪

    We discuss the leptonic ALP portal as a simple scenario that connects observed discrepancies in anomalous magnetic moments to the Dark Matter relic abundance. In this framework an axion-like particle in the multi-MeV range couples to SM leptons and a DM fermion, with mass above the ALP mass but below a GeV. The ALP contributes to $(g-2{)}_{\mu }$ and $(g-2{)}_e$ dominantly through 2-loop Barr-Zee diagrams, while the DM abundance is generated by $p$-wave annihilation to ALP pairs. Constraints from beam-dump experiments, colliders and CMB probes are very stringent, and restrict the viable parameter space to a rather narrow region that will be tested in the near future.

    hep-phastro-ph.COPRD(2024)·35 citations
23. 23*

    Riding the dark matter wave: Novel limits on general dark photons from LISA Pathfinder

    Jonas Frerick🇩🇪 · Joerg Jaeckel🇩🇪 · Felix Kahlhoefer🇩🇪 · Kai Schmidt-Hoberg🇩🇪

    We note the possibility to perform a parametrically improved search for gauged baryon ($B$) and baryon minus lepton ($B-L$) Dark Photon Dark Matter (DPDM) using auxiliary channel data from LISA Pathfinder. In particular we use the measurement of the differential movement between the test masses (TMs) and the space craft (SC) which is nearly as sensitive as the tracking between the two TMs. TMs and SC are made from different materials and therefore have different charge-to-mass ratios for both $B-L$ and $B$. Thus, the surrounding DPDM field induces a relative acceleration of nearly constant frequency. For the case of $B-L$, we find that LISA Pathfinder can constrain previously unexplored parameter space, providing the world leading limits in the mass range $4\cdot 10^{-19}\text{eV}<m<3\cdot 10^{-17}\text{eV}$. This limit can easily be recast also for dark photons that arise from gauging other global symmetries of the SM.

    hep-phastro-ph.COgr-qcPLB(2024)·23 citations
24. 24*

    Rescuing Gravitational-Reheating in Chaotic Inflation

    Basabendu Barman🇮🇳 · Nicolás Bernal🇦🇪 · Javier Rubio🇪🇸

    We show, within the single-field inflationary paradigm, that a linear non-minimal interaction $\xi M_P\varphi R$ between the inflaton field $\varphi$ and the Ricci scalar $R$ can result in successful inflation that concludes with an efficient heating of the Universe via perturbative decays of the inflaton, aided entirely by gravity. Considering the inflaton field to oscillate in a quadratic potential, we find that $\mathcal{O}(10^{-1})\lesssim \xi \lesssim \mathcal{O}(10^2)$ is required to satisfy the observational bounds from Cosmic Microwave Background (CMB) and Big Bang Nucleosynthesis (BBN). Interestingly, the upper bound on the non-minimal coupling guarantees a tensor-to-scalar ratio $r\gtrsim 10^{-4}$, within the range of current and future planned experiments. We also discuss implications of dark matter production, along with the potential generation of the matter-antimatter asymmetry resulting from inflaton decay, through the same gravity portal.

    hep-phastro-ph.COJCAP(2024)·24 citations
25. 25*

    Effects of Annihilation with Low-Energy Neutrinos on High-Energy Neutrinos from Binary Neutron Star Mergers and Rare Core-Collapse Supernovae

    Gang Guo🇨🇳 · Yong-Zhong Qian🇺🇸 · Meng-Ru Wu🇹🇼

    We explore the possibility that high-energy (HE) neutrinos produced from choked jets can be annihilated with low-energy (LE) neutrinos emitted from the accretion disk around a black hole in binary neutron star mergers and rare core-collapse supernovae. For HE neutrinos produced close to the stellar center ($\lesssim 10^9-10^{12}$ cm), we find that the emerging all-flavor spectrum for neutrinos of $E\gtrsim 0.1-1$ PeV could be modified by a factor $E^{-n}$ with $n\gtrsim 0.4-0.5$ under realistic conditions. Flavor evolution of LE neutrinos does not affect this result but can change the emerging flavor composition of HE neutrinos. As a consequence, the above annihilation effect may need to be considered for HE neutrinos produced from choked jets at small radii. We briefly discuss the annihilation effects for different HE neutrino production models and point out that such effects could be tested through precise measurements of the diffuse neutrino spectrum and flavor composition.

    ↳ astro-ph.HEastro-ph.SRhep-phPRD(2024)·3 citations
26. 26*

    Inflationary models constrained by reheating

    Gabriel German🇲🇽 · Juan Carlos Hidalgo🇲🇽 · Luis E. Padilla🇲🇽

    The study of reheating in inflationary models is crucial for understanding the early universe and gaining insights into inflationary dynamics and parameters. The reheating temperature $T_{re}$ and the duration of the reheating phase, quantified by the number of $e$-folds $N_{re}$, have significant implications for particle production, thermalization, and the primordial power spectrum. The duration of reheating affects particle abundance, including dark matter, and shapes the primordial power spectrum and cosmic microwave background anisotropies. By combining cosmological observations and theoretical considerations, we can constrain both $T_{re}$ and $N_{re}$, which in turn constrain the spectral index $n_s$, tensor-to-scalar ratio $r$, and inflation model parameters. Utilizing consistency relations among observables, such as $n_s$ and $r$, provides additional constraints on inflationary models and determines bounds for other observables like the running of the scalar spectral index. These bounds are valuable for assessing the viability of models and can serve to specify priors in Bayesian analyses of specific models. As an example of how to proceed, we study in detail a particular case of a generalized $\alpha$-attractor model that accurately reproduces observed quantities. We present equations for the conditions of instantaneous reheating, establish consistency relations, and explore the generalized $\alpha$-attractor model using cosmological data.

    ↳ astro-ph.COgr-qchep-phEur.Phys.J.Plus(2024)·15 citations
27. 27*

    Recent Progress in Leptonic and Semileptonic Decays of Charmed Hadrons

    Bai-Cian Ke🇨🇳 · Jonna Koponen🇩🇪 · Hai-Bo Li🇨🇳 · Yangheng Zheng🇨🇳

    We present a comprehensive review of purely leptonic and semileptonic decays of $D^{0(+)}$, $D_s^{+}$, and charmed baryons (including ${\Lambda }_c^{+}$, ${\Xi }_c$ and ${\Omega }_c$). The precise studies of these decays help deepen our understanding and knowledge of quantum chromodynamics via measuring decay constants and form factors, and test the Standard Model through examining the unitarity of Cabibbo-Kobayashi-Maskawa matrix and lepton flavor universality. We give an overview of the theoretical and experimental tools before discussing the recent progress. The data sets collected by BESIII near the production thresholds of $D\bar{D}$, $D_s^{(\ast )+}{D}_s^{(\ast )-}$ and ${\Lambda }_c^{+}{\bar{\Lambda }}_c^{-}$ offer important opportunities for studies of charm physics.

    ↳ hep-exhep-lathep-phAnn.Rev.Nucl.Part.Sci.(2023)·85 citations
28. 28*

    On the Axion Electrodynamics in a two-dimensional slab and the Casimir effect

    Iver Brevik🇳🇴 · Masud Chaichian🇫🇮 · Amedeo M. Favitta🇮🇹

    We analyze the Axion Electrodynamics in a two-dimensional slab of finite width $L$ containing a homogeneous and isotropic dielectric medium with constant permittivity and permeability. We start from the known decomposition of modes in the nonaxion case and then solve perturbatively the governing equations for the electromagnetic fields to which the axions are also coupled. This is a natural approach, since the finiteness of $L$ destroys the spatial invariance of the theory in the $z$ direction normal to the plates. In this way we derive the value of the axion-generated rotation angle of the electric and magnetic fields after their passage through the slab, and use the obtained results to calculate the Casimir force between the two conducting plates. Our calculations make use of the same method as previously outlined in \cite{hoye20} for the case of Casimir calculations in chiral media and extend former results on the Casimir force in the Axion Electrodynamics.

    ↳ hep-thhep-phInt.J.Mod.Phys.A(2024)·4 citations
29. 29*

    Higher logarithms and $\epsilon$-poles for the MS-like renormalization prescriptions

    Nikolai Meshcheriakov🇷🇺 · Victoria Shatalova🇷🇺 · Konstantin Stepanyantz🇷🇺

    We consider a version of dimensional regularization (reduction) in which the dimensionful regularization parameter $\Lambda$ is in general different from the renormalization scale $\mu$. Then in the scheme analogous to the minimal subtraction the renormalization constants contain $\epsilon$-poles, powers of $\ln \Lambda /\mu$, and mixed terms of the structure ${\epsilon }^{-q}{\ln }^p\Lambda /\mu$. For the MS-like schemes we present explicit expressions for the coefficients at all these structures which relate them to the coefficients in the renormalization group functions, namely in the $\beta$-function and in the anomalous dimension. In particular, for the pure $\epsilon$-poles we present explicit solutions of the 't~Hooft pole equations. Also we construct simple all-loop expressions for the renormalization constants (also written in terms of the renormalization group functions) which produce all $\epsilon$-poles and logarithms and establish a number of relations between various coefficients at $\epsilon$-poles and logarithms. The results are illustrated by some examples.

    ↳ hep-thhep-phJHEP(2023)·8 citations
30. 30*

    Trans-Planckian censorship constraints on properties and cosmological applications of axion-like fields

    David Shlivko🇺🇸

    We use the Trans-Planckian Censorship Conjecture (TCC) to constrain the decay constants $f$ characterizing a set of N identical axion-like fields with cosine potentials, improving upon the precision of other Swampland conjectures and existing string-theoretic arguments. We find that consistency with the TCC requires any such set of axion-like fields to satisfy $f\sqrt{N}\lesssim 0.6M_{pl}$, where $M_{pl}$ is the reduced Planck mass. We show that this bound makes models of axion-driven inflation incapable of simultaneously producing the required number of e-foldings and the observed scalar spectral tilt. In contrast, we find that models of axion quintessence can be simultaneously compatible with the TCC and observational data, provided that the axions' initial field values are set near the maxima of their potentials to within roughly $\pm \frac{\pi }{5}f$.

    ↳ hep-thastro-ph.COgr-qchep-phPLB(2023)·5 citations
31. 31*

    Exploring Axions through the Photon Ring of a Spherically Symmetric Black Hole

    Sourov Roy🇮🇳 · Pratick Sarkar🇮🇳 · Subhadip Sau🇮🇳 · Soumitra SenGupta🇮🇳

    In this study, we examine the phenomenon of photon axion conversion occurring in the spacetime surrounding a black hole. Specifically, we focus on the potential existence of a magnetic field around the supermassive black hole M87*, which could facilitate the conversion of photons into axions in close proximity to the photon sphere. While photons traverse through the curved spacetime, they spend time near the photon sphere, where conversion of these photons into axions takes place. Consequently, this process leads to a decrease in the intensity of the black hole's photon ring. To explore the possibilities of detecting these hypothetical axion particles, we propose observing the photon sphere using higher resolution telescopes. By doing so, we can gain valuable insights into the conversion mechanism as well as the nature of the spherically symmetric black hole geometry. Moreover, we also investigate how the photon ring luminosities are affected if the black hole possesses a charge parameter. For instance apart from U(1) electric charge, the presence of extra dimension may induce a {\em tidal charge} with a characteristic signature. It is important to note that the success of the conversion mechanism relies on the axion-photon coupling and mass. As a result, the modified luminosity of the black hole's photon ring offers a valuable means of constraining the axion's mass and coupling parameter within a certain range. Thus our findings contribute to a better understanding of photon axion conversion in the environment of a black hole spacetime and helps us explore the possible existence of extra spatial dimension.

    ↳ gr-qchep-phhep-thJCAP(2023)·10 citations
32. 32*

    Waiting for Inflation: A New Initial State for the Universe

    Brandon Melcher🇺🇸 · Arnab Pradhan🇺🇸 · Scott Watson🇺🇸

    We propose a cosmological lingering phase for the initial state prior to inflation which would help address the singularity problem of inflation. The universe begins with a constant (Hagedorn) temperature and then transitions into an inflationary universe while preserving the Null Energy Condition (NEC). In such a universe time is presumably emergent, calling the age of the universe into question. We first consider the phase space of positive spatial curvature models within General Relativity and with matter sources that respect the NEC. Depending on the duration of the post-lingering inflation these models can produce a small amount of observable spatial curvature in the Cosmic Microwave Background. We also discuss how lingering can arise with or without spatial curvature in theories of quantum gravity when considering the thermodynamic scaling of particles and its impact on the early universe. The string theory dilaton is essential to the dynamics. There are many open questions that remain.

    ↳ hep-thastro-ph.COhep-phPRD(2024)·6 citations
33. 33*

    Dynamical tidal Love numbers of Kerr-like compact objects

    Sumanta Chakraborty🇮🇳 · Elisa Maggio🇩🇪 · Michela Silvestrini🇮🇹 · Paolo Pani🇮🇹

    We develop a framework to compute the tidal response of a Kerr-like compact object in terms of its reflectivity, compactness, and spin, both in the static and the frequency-dependent case. Here we focus on the low-frequency regime, which can be solved fully analytically. We highlight some remarkable novel features, in particular: i) Even in the zero-frequency limit, the tidal Love numbers (TLNs) depend on the linear-in-frequency dependence of the object's reflectivity in a nontrivial way. ii) Intriguingly, the static limit of the frequency-dependent TLNs is discontinuous, therefore the static TLNs differ from the static limit of the (phenomenologically more interesting) frequency-dependent TLNs. This shows that earlier findings regarding the static TLNs of ultracompact objects correspond to a measure-zero region in the parameter space, though the logarithmic behavior of the TLNs in the black hole limit is retained. iii) In the non-rotating case, the TLNs generically vanish in the zero-frequency limit (just like for a black hole), except when the reflectivity is $\mathcal{R}=1+\mathcal{O}(M\omega )$, in which case they vanish with a model-dependent scaling, which is generically logarithmic, in the black-hole limit. The TLNs initially grow with frequency, for any nonzero reflectivity, and then display oscillations and resonances tied up with the quasi-normal modes of the object. iv) For rotating compact objects, the TLNs decrease when the reflectivity decreases or the rotation parameter increases. Our results lay the theoretical groundwork to develop model-independent tests of the nature of compact objects using tidal effects in gravitational-wave signals.

    ↳ gr-qcastro-ph.HEhep-phhep-thPRD(2024)·58 citations
34. 34*

    Aspects of Thermal QCD Phenomenology at Intermediate Gauge/'t Hooft Coupling from String/M-Theory, (HD) Gravity Islands, and Multiverse

    Gopal Yadav🇮🇳

    As applications of arXiv:2004.07259, the first part of the thesis is based on (i) arXiv:2011.04660 wherein we computed the low energy coupling constants of SU(3) chiral perturbation theory at NLO in the chiral expansion in the chiral limit, from the type IIA string dual inclusive of $\mathcal{O}(R^4)$ corrections and found a novel HD-large-$N$ connection; (ii) arXiv:2108.05372, arXiv:2203.11959 wherein we discussed confinement-deconfinement phase transition in thermal QCD-like theories at intermediate coupling in the absence/presence of rotation and observed (a) a novel "UV-IR" mixing, (b) "Flavor Memory" effect, (c) M$\chi$PT compatibility,(d) non-renormalization of deconfinement temperature $T_c$ beyond one loop in the zero instanton sector, and (e) found that the $T_c$ of rotating QGP decreases when angular velocity of rotating cylindrical black hole increases and vice-versa. In the second part of thesis, we obtained Page curves of Reissner-Nordström black holes in the presence of $\mathcal{O}(R^2)$ terms and black holes with multiple horizons in arXiv:2204.11882 and arXiv:2210.00331 respectively. In arXiv:2207.04048, we constructed a doubly holographic setup for a non-conformal bath (thermal QCD) in $\mathcal{M}$-theory background with the inclusion of $\mathcal{O}(R^4)$ terms and obtained the Page curve of an eternal neutral black hole for massless graviton localized on an ETW-"brane"/(Fluxed) hypersurface. Multiverse is described as the setup of 2n anti de-Sitter (AdS) or de-Sitter branes embedded in the corresponding bulk (arXiv:2301.06151). Since all the universes can communicate with each other due to transparent boundary conditions at the defect, therefore one could exchange information between any universes. This setup is also used to obtain the Page curve of the Schwarzschild de-Sitter black hole, which has two horizons.

    ↳ hep-thgr-qchep-ph4 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.