Wed·Oct 13, 2021Wednesday·October 13, 2021

1. 01*

   New physics footprints in the angular distribution of $B_s\to D_s^{\ast }(\to D_s\gamma ,D_s\pi )\tau \nu$ decays

   Nilakshi Das🇮🇳 · Rupak Dutta🇮🇳

   Hints of lepton flavor universality violation observed in various flavor ratios such as $R_D$, $R_{D^{\ast }}$, $R_{J/\psi }$, $P_{\tau }^{D^{\ast }}$ and $F_L^{D^{\ast }}$ in $B\to D^{(\ast )}\ell \nu$ and $B_c\to J/\psi \ell \nu$ charge current decays have opened new avenues to search for indirect evidences of beyond the standard model physics. Motivated by these anomalies, we perform a detailed angular analysis of $B_s\to D_s^{\ast }(\to D_s\gamma ,D_s\pi )\ell \nu$ decays that proceed via similar $b\to c\ell \nu$ quark level transition. We use the most general effective Hamiltonian for $b\to cl\nu$ process and give predictions of several $q^2$ and $\cos \theta$ dependent observables for the $B_s\to D_s^{\ast }(\to D_s\gamma ,D_s\pi )\ell \nu$ decays in the standard model and in the presence of various real and complex new physics couplings. The results pertaining to this decay are competent to address the anomalies in the charge current sector.

   hep-phPRD(2022)·12 citations
2. 02*

   Fine Structure of Pentaquark Multiplets in the Dynamical Diquark Model

   Jesse F. Giron🇺🇸 · Richard F. Lebed🇺🇸

   We apply the dynamical diquark model to predict the spectrum of hidden-charm pentaquark states in both unflavored and open-strange sectors. Using only Hamiltonian parameters introduced in the tetraquark $S$- and $P$-wave multiplets, the model naturally produces the level spacing supported by the most recent LHCb results for $P_c$ structures. Furthermore, using model inputs obtained from data of hidden-charm, open-strange tetraquarks ($Z_{cs}$), we predict the spectrum of $P_{cs}$ states, including the recently observed $P_{cs}(4459)$. We find all pentaquark candidates observed to date to belong to the $1P$ multiplet and hence have positive parity.

   hep-phPRD(2021)·41 citations
3. 03*

   Glueball-glueball scattering and the glueballonium

   Francesco Giacosa🇵🇱 · Alessandro Pilloni🇮🇹 · Enrico Trotti🇵🇱

   The scalar glueball $G$ is the lightest particle of the Yang-Mills sector of QCD, with a lattice predicted mass of about $m_G\simeq 1.7$ GeV. It is natural to investigate glueball-glueball scattering and the possible emergence of a bound state, that we call glueballonium. We perform this study in the context of a widely used dilaton potential, that depends on a single dimensionful parameter ${\Lambda }_G$. We consider a unitarization prescription that allows us to predict the lowest partial waves in the elastic window. These quantities can be in principle calculated on the lattice, thus offering possibility for testing the validity of the dilaton potential and an independent determination of its parameter. Moreover, we also show that a stable glueballonium exists if ${\Lambda }_G$ is small enough. In particular, for ${\Lambda }_G$ compatible with the expectations from the gluon condensate, the glueballonium has a mass of about $3.4$ GeV.

   hep-phhep-thEPJC(2022)·15 citations
4. 04*

   Model-independent analysis on $R(K^{(\ast )})$

   Jong-Phil Lee🇰🇷

   We analyze the lepton-universality violating $B\to K^{(\ast )}{\ell }^{+}{\ell }^{-}$ puzzle $R(K^{(\ast )})$ in a model-independent way. The branching ratio $\mathrm{Br}(B_s\to {\mu }^{+}{\mu }^{-})$ is also considered as a main constraint. We show how the branching ratio restricts the allowed region of the parameter space, and investigate new physics effects on the electronic as well as muonic sector in $R(K^{(\ast )})$. Within a reasonable range of parameters we find that the new physics scale goes up to $\sim 5$ TeV, and the new physics effects on the Wilson coefficient is $-1\lesssim C_{9NP}^{\mu }\lesssim 0$.

   hep-phJ.Korean Phys.Soc.(2022)·8 citations
5. 05*

   Flavored Gauge-Mediated Supersymmetry Breaking Models with Discrete Non-Abelian Symmetries

   Shu Tian Eu🇺🇸 · Lisa L. Everett🇺🇸 · Todd Garon🇺🇸 · Neil Leonard🇺🇸

   We investigate flavored gauge mediation models in which the Higgs and messenger doublets are embedded in multiplets of the discrete non-Abelian symmetry S3. In these theories, the S3 symmetry correlates the flavor structure of the quark and lepton Yukawa couplings with the structure of the messenger Yukawa couplings that contribute to the soft supersymmetry breaking mass parameters. We provide a systematic exploration of possible scenarios within this framework that can accommodate hierarchical quark and charged lepton masses, and examine the resulting phenomenological implications in each case. We find a heavier spectrum for the superpartner masses compared to flavored gauge mediation models controlled by Abelian symmetries, which can be directly traced back to the need in our scenarios for two vectorlike pairs of messenger fields for viable electroweak symmetry breaking.

   hep-phPRD(2022)·3 citations
6. 06*

   PNJL model at zero temperature: three-flavor case

   O. A. Mattos🇧🇷 · T. Frederico🇧🇷 · C. H. Lenzi🇧🇷 · M. Dutra🇧🇷 · O. Lourenço🇧🇷

   We propose a three-flavor version of the Polyakov-Nambu-Jona-Lasino (PNJL) model at zero temperature regime, by implementing a traced Polyakov loop ($\Phi$) dependence in the scalar, vector and 't Hooft channel strengths. We study the thermodynamics of this model, named as PNJL0, with special attention for the first order confinement/deconfinement phase transition for which $\Phi$ is the order parameter. For the symmetric quark matter case, an interesting feature observed is a strong reduction of the constituent strange quark mass ($M_s$) at the chemical potential related to point where deconfinement takes place. The emergence of $\Phi$ favors the restoration of chiral symmetry even for the strange quark. We also investigate the charge neutral system of quarks and leptons in weak equilibrium. As an application, we construct a hadron-quark phase transition with a density dependent hadronic model coupled to the SU(3) PNJL0 model. In this case, the quark side is composed by deconfined particles. This approach is used to determine mass-radius profiles compatible with recent data from the Neutron Star Interior Composition Explorer (NICER) mission.

   hep-phPRD(2021)·14 citations
7. 07*

   Evaporating Primordial Black Holes in Gamma Ray and Neutrino Telescopes

   Antonio Capanema🇧🇷 · AmirFarzan Esmaeili🇧🇷 · Arman Esmaili🇧🇷

   A primordial black hole in the last stages of evaporation and located in the local neighborhood can produce a detectable signal in gamma ray and neutrino telescopes. We re-evaluate the expected gamma ray and neutrino fluxes from these transient point events and discuss the consequences for existing constraints. For gamma rays we improve the current bounds by a factor of few, while for neutrinos we obtain significantly different results than the existing literature. The capability and advantages of neutrino telescopes in the search for primordial black holes is discussed thoroughly. The correlations of gamma ray and neutrino energy and time profiles will be promoted as a powerful tool in identifying the primordial black holes, in case of detection.

   hep-phastro-ph.HEJCAP(2021)·31 citations
8. 08*

   Updated sensitivity of DUNE in 3+1 scenario with far and near detectors

   Monojit Ghosh🇮🇳 · Rukmani Mohanta🇮🇳

   In this paper we present the updated physics sensitivity of DUNE in presence of a light sterile neutrino with both far and near detectors. In the previous studies, the sensitivities were obtained using the configuration of DUNE as described in the conceptual design report (CDR). In this article, we consider the configuration of DUNE as given in the technical design report (TDR) and study the capability of this experiment to constrain the sterile mixing parameters as well as its capability to measure the standard oscillation parameters in 3+1 scenario. Our results show that in 3+1 scenario, the sensitivity of DUNE to measure the mass hierarchy, octant and CP violation deteriorates if we only consider the far detector. However, a combined analysis of far and near detector improves the sensitivity.

   hep-phhep-exEur.Phys.J.ST(2022)·3 citations
9. 09*

   Free Streaming Length of Axion-Like Particle After Oscillon/ I-ball Decays

   Kaname Imagawa🇯🇵 · Masahiro Kawasaki🇯🇵 · Kai Murai🇯🇵 · Hiromasa Nakatsuka🇯🇵 · Eisuke Sonomoto🇯🇵

   Axion-like particles (ALPs) are pseudoscalar bosons predicted by string theory. The ALPs have a shallower potential than a quadratic one, which induces the instability and can form the solitonic object called oscillon/I-ball. Although the lifetime of oscillons can be very long for some type of potentials, they finally decay until the present. We perform the numerical lattice simulations to investigate the decay process of oscillons and evaluate the averaged momentum of ALPs emitted from the oscillon decay. It is found that, if oscillons decay in the early universe, the free-streaming length of ALPs becomes too long to explain the small-scale observations of the matter power spectrum. We show that oscillons with long lifetimes can change the density fluctuations on small scales, which leads to stringent constraints on the ALP mass and the oscillon lifetime.

   hep-phastro-ph.COJCAP(2023)·6 citations
10. 10*

    Light-cone distribution amplitudes of the nucleon and $\Delta$ baryon

    June-Young Kim🇩🇪 · Hyun-Chul Kim🇰🇷 · Maxim V. Polyakov🇩🇪

    We investigate the light-cone wave functions and leading-twist distribution amplitudes for the nucleon and $\Delta$ baryon within the framework of the chiral quark-soliton model. The baryon wave function consists of the valence quark and vacuum wave functions. The vacuum wave functions generate all possible higher Fock states by expanding them. We find that it is essential to consider the five-quark component and relativistic corrections to evaluate the distribution amplitudes of the nucleon and $\Delta$ isobar. Having taken into account them, we derive the distribution amplitudes. The results are in good agreement with the lattice data.

    hep-phhep-latJHEP(2021)·12 citations
11. 11*

    Searching for hidden matter with long-range angular correlations at $e^{+}{e}^{-}$ colliders

    Redamy Pérez-Ramos🇫🇷 · Miguel-Angel Sanchis-Lozano🇪🇸 · Edward K. Sarkisyan-Grinbaum🇨🇭

    The analysis of azimuthal correlations in multiparticle production can be useful to uncover the existence of new physics beyond the Standard Model, e.g., Hidden Valley, in $e^{+}{e}^{-}$ annihilation at high energies. In this paper, based on previous theoretical studies and using PYTHIA8 event generator, it is found that both azimuthal and rapidity long-range correlations are enhanced due to the presence of a new stage of matter on top of the QCD partonic cascade. Ridge structures, similar to those observed at the LHC, show up providing a possible signature of new physics at future $e^{+}{e}^{-}$ colliders.

    hep-phhep-exhep-thPRD(2022)·5 citations
12. 12*

    BSM Developments and Tools

    Tomás E. Gonzalo🇩🇪

    In this conference paper I introduce a selection of BSM tools and describe their most recent developments. I choose to focus on tools for the reinterpretation of LHC searches, tools that compute dark matter constraints, beyond-the-Standard-Model (BSM) inference tools, and tools that calculate amplitudes and cross sections directly from the Lagrangian.

    hep-phPoS(2021)·1 citation
13. 13*

    QSNET, a network of clocks for measuring the stability of fundamental constants

    G. Barontini🇬🇧 · V. Boyer🇬🇧 · X. Calmet🇬🇧 · N. J. Fitch🇬🇧 · E. M. Forgan🇬🇧 · R. M. Godun🇬🇧 · J. Goldwin🇬🇧 · V. Guarrera🇬🇧 · I. R. Hill🇬🇧 · M. Jeong🇬🇧 · M. Keller🇬🇧 · F. Kuipers🇬🇧 and 10 other authors

    The QSNET consortium is building a UK network of next-generation atomic and molecular clocks that will achieve unprecedented sensitivity in testing variations of the fine structure constant, $\alpha$, and the electron-to-proton mass ratio, $\mu$. This in turn will provide more stringent constraints on a wide range of fundamental and phenomenological theories beyond the Standard Model and on dark matter models.

    hep-phastro-ph.COgr-qchep-ex+1Proc.SPIE Int.Soc.Opt.Eng.(2021)·7 citations
14. 14*

    Scalar resonances in the hadronic light-by-light contribution to the muon $(g-2)$

    Luigi Cappiello🇮🇹 · Oscar Catà🇩🇪 · Giancarlo D'Ambrosio🇮🇹

    We evaluate the contribution of scalar mesons to the hadronic light-by-light piece of the muon anomalous magnetic moment, using a warped five-dimensional model and holographic methods. We assess the contribution of the lightest, sub-GeV scalars $\sigma (500)$, $a_0(980)$ and $f_0(980)$ together with their associated towers of excited states, which the model generates automatically. Our results point at a clearly negative contribution, overwhelmingly dominated by the $\sigma (500)$ meson, that we estimate at $a_{\mu }^{\mathrm{HLbL},\mathrm{S}}=-9(2)\cdot 10^{-11}$. This number is in very good agreement with the most recent determinations from dispersive analyses.

    hep-phPRD(2022)·23 citations
15. 15*

    Disentangling soft and collinear effects in QCD parton showers

    Leif Gellersen🇸🇪 · Stefan Höche🇺🇸 · Stefan Prestel🇸🇪

    We introduce a method for the separation of soft and collinear logarithms in QCD parton evolution at $\mathcal{O}({\alpha }_s^2)$ and at leading color. Using an implementation of the technique in the Dire parton shower, we analyze the numerical impact of genuine triple-collinear corrections from quark pair emission in $e^{+}{e}^{-}\to$ hadrons.

    hep-phPRD(2022)·43 citations
16. 16*

    Searching for Dark Matter with circularly polarised photons from the Galactic Centre

    Marina Cermeño🇧🇪 · Céline Degrande🇧🇪 · Luca Mantani🇧🇪

    Conventional indirect dark matter (DM) searches look for an excess in the electromagnetic emission from the sky that cannot be attributed to known astrophysical sources, but its polarisation has not been explored to date. In this proceeding, we argue that photon polarisation is an important feature to understand new physics interactions. In particular, circular polarisation can be generated from Beyond the Standard Model interactions if they violate parity and there is an asymmetry in the number density of the initial state particles which participate in the interaction. We consider a simplified model for fermionic (Majorana) DM and study the circularly polarised gamma rays below 10 GeV from DM cosmic ray electron interactions. We study the differential flux of positive and negative polarised photons from the Galactic Centre and show that the degree of circular polarization can reach up to 90%. Finally, we discuss the detection prospects of this signal in future experiments.

    hep-phPoS(2022)·1 citation
17. 17*

    Pion GPDs: A path toward phenomenology

    José Manuel Morgado Chavez🇪🇸 · Valerio Bertone🇫🇷 · Feliciano De Soto Borrero🇪🇸 · Maxime Defurne🇫🇷 · Cédric Mezrag🇫🇷 · Hervé Moutarde🇫🇷 · José Rodríguez-Quintero🇪🇸 · Jorge Segovia🇪🇸

    We introduce a new family of Generalised Parton Distribution models able to fulfil by construction all the theoretical properties imposed by QCD. These models are built on standard Parton Distribution Functions and extended to off-forward kinematics through a well-defined procedure. We apply this strategy on the pion, first handling a simple but insightful algebraic model, and then exploiting state-of-the-art computations obtained in continuum QCD. We compare these models with a more standard one relying on an xFitter extraction of the pion Parton Distribution Functions. The results for both quark and gluon Generalised Parton Distributions are presented and exploited for calculation of Electromagnetic, Gravitational and Compton Form Factors. Results on the latter highlight the relevance of next-to-leading order corrections, even in the so-called valence region.

    hep-phnucl-thPRD(2022)·59 citations
18. 18*

    X17 discovery potential in the $\gamma N\to e^{+}{e}^{-}N$ process at electron scattering facilities

    Johannes Backens🇩🇪 · Marc Vanderhaeghen🇩🇪

    We propose a direct search for the X17 particle, which was conjectured to explain the ATOMKI ${}^8$Be and ${}^4$He anomalies, through the dilepton photoproduction process on a nucleon in the photon energy range below or around the pion production threshold. For the scenarios of either pseudoscalar, vector, or axial-vector quantum numbers of the conjectured X17, we use existing constraints to estimate the X17 signal process. For dilepton resolutions which have been achieved in previous experiments, a signal-to-background ratio of up to an order of magnitude is found for a neutron target, and in particular for the pseudoscalar and vector X17 scenarios.

    hep-phnucl-thPRL(2022)·12 citations
19. 19*

    Elucidating the internal structure of hadrons through direct photon production

    David F. Rentería-Estrada🇲🇽 · Roger J. Hernández-Pinto🇲🇽 · German F. R. Sborlini🇩🇪

    The accurate description of the internal structure of hadrons is a very challenging task. In order to compare the predictions with the highly-accurate experimental data, it is necessary to control any possible source of theoretical uncertainties. Thus, we can use the information extracted from final state measurement to constrain our knowledge about the internal structure of hadrons. In this work, we describe how direct photon production can be exploited to unveil details about the partonic distributions inside protons. Also, we explain how to describe QCD-QED corrections to hadron plus photon production at colliders, focusing on the accurate reconstruction of the partonic momentum fractions from experimentally accessible observables.

    hep-phPoS(2022)·0 citations
20. 20*

    Padé approximants to $B\to \pi \ell {\nu }_{\ell }$ and $B_s\to K\ell {\nu }_{\ell }$ and determination of $|V_{ub}|$

    Sergi Gonzàlez-Solís🇺🇸 · Pere Masjuan🇪🇸 · Camilo Rojas🇪🇸

    In light of the first observation of the semileptonic decay $B_s^0\to K^{-}{\mu }^{+}{\nu }_{\mu }$ by the LHCb collaboration, we revisit the determination of the CKM parameter $|V_{ub}|$ from exclusive semileptonic $B$-meson decays. A controlled theoretical input on the Standard Model $B\to \pi$ and $B_s\to K$ vector and scalar form factors from Lattice QCD in the large $q^2$ region, in combination with experimental measurements of the differential $B\to \pi \ell {\nu }_{\ell }$ and $B_s^0\to K^{-}{\mu }^{+}{\nu }_{\mu }$ branching ratio distributions, has allowed us determine $|V_{ub}|=3.86(11)\times 10^{-3}$ and $|V_{ub}|=3.58(9)\times 10^{-3}$ from the analyses of the individual decay channels, respectively, and $|V_{ub}|=3.68(5)\times 10^{-3}$ from a simultaneous analysis of both decays, which is only a $1.4\%$ error and differs by $1.8\sigma$ with respect to the value from inclusive determinations $|V_{ub}|=4.25(12{)}_{-14}^{+15}(23)\times 10^{-3}$. Our results are based on the use of Padé approximants to the participating form factors, highlight the importance of the decay $B_s\to K\mu {\nu }_{\mu }$ in complementing the traditional $B\to \pi \ell {\nu }_{\ell }$ one in the exclusive determination of $|V_{ub}|$, and allow obtain, to the best of our knowledge, the first correlated results for the $B\to \pi$ and $B_s\to K$ vector and scalar form factors. We hope that our study strengthens the case for precise measurements of the differential $B_s\to K\ell {\nu }_{\ell }$ decay rate with a finer resolution of the $q^2$ bins, as it would definitely allow achieving more conclusive results for $|V_{ub}|$.

    hep-phhep-exhep-latPRD(2021)·20 citations
21. 21*

    Evidence for the maximally entangled low $x$ proton in Deep Inelastic Scattering from H1 data

    Martin Hentschinski🇲🇽 · Krzysztof Kutak🇵🇱

    We investigate the proposal by Kharzeev and Levin of a maximally entangled proton wave function in Deep Inelastic Scattering at low $x$ and the proposed relation between parton number and final state hadron multiplicity. Contrary to the original formulation we determine partonic entropy from the sum of gluon and quark distribution functions at low $x$, which we obtain from an unintegrated gluon distribution subject to next-to-leading order Balitsky-Fadin-Kuraev-Lipatov evolution. We find for this framework very good agreement with H1 data. We furthermore provide a comparison based on NNPDF parton distribution functions at both next-to-next-to-leading order and next-to-next-to-leading with small $x$ resummation, where the latter provides an acceptable description of data.

    hep-phhep-exquant-phEPJC(2022)·57 citations
22. 22*

    Low-Energy Signals from the Formation of Dark Matter-Nuclear Bound States

    Asher Berlin🇺🇸 · Hongwan Liu🇺🇸 · Maxim Pospelov🇺🇸 · Harikrishnan Ramani🇺🇸

    Dark matter particles may bind with nuclei if there exists an attractive force of sufficient strength. We show that a dark photon mediator of mass $\sim (10-100)$ MeV that kinetically mixes with Standard Model electromagnetism at the level of $\sim 10^{-3}$ generates keV-scale binding energies between dark matter and heavy elements, while forbidding the ability to bind with light elements. In underground direct detection experiments, the formation of such bound states liberates keV-scale energy in the form of electrons and photons, giving rise to mono-energetic electronic signals with a time-structure that may contain daily and seasonal modulations. We show that data from liquid-xenon detectors provides exquisite sensitivity to this scenario, constraining the galactic abundance of such dark particles to be at most $\sim 10^{-18}-10^{-12}$ of the galactic dark matter density for masses spanning $\sim (1-10^5)$ GeV. However, an exponentially small fractional abundance of these dark particles is enough to explain the observed electron recoil excess at XENON1T.

    hep-phastro-ph.COhep-exPRD(2022)·11 citations
23. 23*

    Can the GW190814 secondary component be a bosonic dark matter admixed compact star?

    Billy K. K. Lee🇨🇳 · Ming-chung Chu🇨🇳 · Lap-Ming Lin🇨🇳

    We investigate whether the recently observed 2.6 $M_{\odot }$ compact object in the gravitational-wave event GW190814 can be a bosonic dark matter admixed compact star. By considering the three constraints in mass, radius and stability of such an object, we find that if the dark matter is made of QCD axions, their particle mass $m$ is constrained to a range that has already been ruled out by the independent constraint imposed by the stellar-mass black hole superradiance process. The 2.6 $M_{\odot }$ object can still be a neutron star admixed with at least 2.0 $M_{\odot }$ of dark matter made of axion-like particles (or even a pure axion-like particle star) if $2\times 10^{-11}$ eV $\le m\le 2.4\times 10^{-11}$ eV ($2.9\times 10^{-11}$ eV $\le m\le 3.2\times 10^{-11}$ eV) and with decay constant $f\ge 8\times 10^{17}$ GeV.

    ↳ astro-ph.HEgr-qchep-phApJ(2021)·34 citations
24. 24*

    On the AdS/CFT correspondence and quantum entanglement

    Badis Ydri🇩🇿

    String theory provides one of the most deepest insights into quantum gravity. Its single most central and profound result is the gauge/gravity duality, i.e. the emergence of gravity from gauge theory. The two examples of M(atrix)-theory and the AdS/CFT correspondence, together with the fundamental phenomena of quantum entanglement, are of paramount importance to many fundamental problems including the physics of black holes (in particular to the information loss paradox), the emergence of spacetime geometry and to the problem of the reconciliation of general relativity and quantum mechanics. In this article an account of the AdS/CFT correspondence and the role of quantum entanglement in the emergence of spacetime geometry using strictly the language of quantum field theory is put forward.

    ↳ hep-thhep-exhep-lathep-ph3 citations
25. 25*

    New generalization of the simplest $\alpha$-attractor $T$ model

    Gabriel German

    The simplest $\alpha$-attractor $T$ model is given by the potential $V=V_0{\tanh }^2(\lambda \varphi /M_{pl})$. However its generalization to the class of models of the type $V=V_0{\tanh }^p(\lambda \varphi /M_{pl})$ is difficult to interpret as a model of inflation for most values of $p$. Keeping the basic model, we propose a new generalization, where the final potential is of the form $V=V_0(1-{\text{sech}}^p(\lambda \varphi /M_{pl}))$, which does not present any of the problems that plague the original generalization, allowing a successful interpretation as a model of inflation for any value of $p$ and, at the same time, providing the potential with a region where reheating can occur for any $p$ (including odd and fractional values) without difficulty. In the cases $p=1,2,4$ we obtain the solutions $r(n_s,N_{ke})$ where $r$ is the tensor-to-scalar ratio, $n_s$ the spectral index and $N_{ke}$ the number of $e$-folds during inflation. We also show how these solutions connect to the ${\varphi }^2$ monomial.

    ↳ astro-ph.COgr-qchep-phhep-thPhys. Rev. D 104, 083015, (2021)
26. 26*

    Hydrodynamic analyses of nuclear collisions in Landau and Eckart frames

    Akihiko Monnai🇯🇵

    Relativistic dissipative hydrodynamic model at finite density is a promising tool for analyzing the dense QCD matter created in the beam energy scan experiments. The hydrodynamic frame can be chosen in the direction of energy flow, which is called the Landau frame, or conserved charge flow, which is called the Eckart frame. In this study, I investigate the stability and causality of full second-order relativistic hydrodynamic equations in the two frames. Then the effects of frame choice on hydrodynamic variables and experimental observables are estimated numerically and are found to be visible on the flow but limited on the rapidity distributions.

    ↳ nucl-thhep-phnucl-exPoS(2022)·0 citations
27. 27*

    Connection between cosmological time and the constants of Nature

    Joao Magueijo🇬🇧

    We examine in greater detail the proposal that time is the conjugate of the constants of nature. Fundamentally distinct times are associated with different constants, a situation often found in "relational time" settings. We show in detail how in regions dominated by a single constant the Hamiltonian constraint can be reframed as a Schrodinger equation in the corresponding time, solved in the connection representation by outgoing-only monochromatic plane waves moving in a "space" that generalizes the Chern-Simons functional. We pay special attention to the issues of unitarity and the measure employed for the inner product. Normalizable superpositions can be built, including solitons, "light-rays" and coherent/squeezed states saturating a Heisenberg uncertainty relation between constants and their times. A healthy classical limit is obtained for factorizable coherent states, both in mono-fluid and multi-fluid situations. For the latter, we show how to deal with transition regions, where one is passing on the baton from one time to to another, and investigate the fate of the subdominant clock. For this purpose minisuperspace is best seen as a dispersive medium, with packets moving with a group speed distinct from the phase speed. We show that the motion of the packets' peaks reproduces the classical limit even during the transition periods, and for subdominant clocks once the transition is over. Deviations from the coherent/semi-classical limit are expected in these cases, however. The fact that we have recently transitioned from a decelerating to an accelerating Universe renders this proposal potentially testable, as explored elsewhere.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2022)·30 citations
28. 28*

    Primordial black hole formation for an anisotropic perfect fluid: Initial conditions and estimation of the threshold

    Ilia Musco🇮🇹 · Theodoros Papanikolaou🇫🇷

    This work investigates the formation of primordial black holes within a radiation fluid with an anisotropic pressure. We focus our attention on the initial conditions describing cosmological perturbations in the super horizon regime, using a covariant form of the equation of state in terms of pressure and energy density gradients. The effect of the anisotropy is to modify the initial shape of the cosmological perturbations with respect to the isotropic case. Using the dependence of the threshold ${\delta }_{\mathrm{c}}$ for primordial black holes with respect to the shape of cosmological perturbations, we estimate here how the threshold is varying with respect to the amplitude of the anisotropy. If this variation is large enough it could lead to a significant variation of the abundance of PBHs.

    ↳ gr-qcastro-ph.COhep-phPRD(2022)·34 citations
29. 29*

    Non-Gaussianities in the Extended EFT of Inflation

    Amjad Ashoorioon🇮🇷 · Ghazal Geshnizjani🇨🇦 · Hyung J. Kim🇨🇦

    In earlier works, we studied the validity of Extended Effective Field Theory of Inflation (EEFToI) in the regime where initial conditions are set with dispersion relations ${\omega }^2\propto k^6$. We had also evaluated and examined the power spectrum for some interesting corners of the parameter space. In this paper, we compute the bispectrum in the EEFToI, take a closer look at the strong coupling constraints and calculate the size of the non-Gaussianities in those regions of parameter space. We also investigate the shape of triangles that contribute to the enhancement of non-Gaussianities in this regime. We find that there are allowed parts of parameter spaces where EEFToI description with initial conditions set with ${\omega }^2\propto k^6$ is sensible and interesting.

    ↳ hep-thastro-ph.COgr-qchep-phJCAP(2022)·4 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.