Wed·Sep 1, 2021Wednesday·September 1, 2021

1. 01*

   Non-minimally Coupled Vector Boson Dark Matter

   Basabendu Barman🇨🇴 · Nicolás Bernal🇨🇴 · Ashmita Das🇮🇳 · Rishav Roshan🇮🇳

   We consider a simple abelian vector dark matter (DM) model, where {\it only} the DM $({\tilde{X}}_{\mu })$ couples non-minimally to the scalar curvature $(\tilde{R})$ of the background spacetime via an operator of the form $\sim {\tilde{X}}_{\mu }{\tilde{X}}^{\mu }\tilde{R}$. By considering the standard freeze-out scenario, we show, it is possible to probe such a non-minimally coupled DM in direct detection experiments for a coupling strength $\xi \sim \mathcal{O}\left(10^{30}\right)$ and DM mass $m_X\lesssim 55$ TeV, satisfying Planck observed relic abundance and perturbative unitarity. We also discuss DM production via freeze-in, governed by the non-minimal coupling, that requires $\xi \lesssim 10^{-5}$ to produce the observed DM abundance over a large range of DM mass depending on the choice of the reheating temperature. We further show, even in the absence of the non-minimal coupling, it is possible to produce the whole observed DM abundance via 2-to-2 scattering of the bath particles mediated by massless gravitons.

   hep-phgr-qchep-thJCAP(2022)·30 citations
2. 02*

   High-dimensional Anomaly Detection with Radiative Return in $e^{+}{e}^{-}$ Collisions

   Julia Gonski🇺🇸 · Jerry Lai🇺🇸 · Benjamin Nachman🇺🇸 · Inês Ochoa🇵🇹

   Experiments at a future $e^{+}{e}^{-}$ collider will be able to search for new particles with masses below the nominal centre-of-mass energy by analyzing collisions with initial-state radiation (radiative return). We show that machine learning methods that use imperfect or missing training labels can achieve sensitivity to generic new particle production in radiative return events. In addition to presenting an application of the classification without labels (CWoLa) search method in $e^{+}{e}^{-}$ collisions, our study combines weak supervision with variable-dimensional information by deploying a deep sets neural network architecture. We have also investigated some of the experimental aspects of anomaly detection in radiative return events and discuss these in the context of future detector design.

   hep-phJHEP(2022)·12 citations
3. 03*

   $a_1$ meson-nucleon coupling constant at finite temperature from the soft-wall AdS/QCD model

   Shahin Mamedov🇦🇿 · Shahnaz Taghiyeva🇦🇿

   We study the temperature dependence of the $a_1$ meson-nucleon coupling constant in the framework of the soft-wall AdS/QCD model with thermal dilaton field. Profile functions for the axial-vector and fermion fields in the AdS-Schwarzschild metric are presented. It is constructed an interaction Lagrangian for the fermion-axial-vector-thermal dilaton fields system in the bulk of space-time. From this Lagrangian integral representation for the $g_{a_{1}NN}$ coupling constant is derived. The temperature dependence of this coupling constant is numerically analyzed.

   hep-phhep-thEPJC(2021)·9 citations
4. 04*

   Matching of Fracture Functions for SIDIS in Target Fragmentation Region

   K.B. Chen🇨🇳 · J.P. Ma🇨🇳 · X.B. Tong🇨🇳

   In the target fragmentation region of Semi-Inclusive Deep Inelastic Scattering, the diffractively produced hadron has small transverse momentum. If it is at order of ${\Lambda }_{QCD}$, it prevents to make predictions with the standard collinear factorization. However, in this case, differential cross-sections can be predicted by the factorization with fracture functions, diffractive parton distributions. If the transverse momentum is much larger than ${\Lambda }_{QCD}$ but much smaller than $Q$ which is the virtuality of the virtual photon, both factorizations apply. In this case, fracture functions can be factorized with collinear parton distributions and fragmentation functions. We study the factorization up to twist-3 level and obtain gauge invariant results. They will be helpful for modeling fracture functions and useful for resummation of large logarithm of the transverse momentum appearing in collinear factorization.

   hep-phJHEP(2021)·15 citations
5. 05*

   Heavy-quark effects on cold quark matter and self-bound stars

   José C. Jiménez🇧🇷 · Eduardo S. Fraga🇧🇷

   Heavy-quark effects on the equation of state for cold and dense quark matter are obtained from perturbative QCD, yielding observables parametrized only by the renormalization scale. In particular, we investigate the thermodynamics of charm quark matter under the constraints of $\beta$ equilibrium and electric charge neutrality in a region of densities where perturbative QCD is, in principle, much more reliable. Finally, we analyze the stability of charm stars, a possible new branch of ultradense, self-bound compact stars, and find that they are unstable under radial oscillations.

   hep-phastro-ph.HEnucl-thEPJ Web Conf.(2022)·0 citations
6. 06*

   Observable signatures of enhanced axion emission from protoneutron stars

   Tobias Fischer🇵🇱 · Pierluca Carenza🇮🇹 · Bryce Fore🇺🇸 · Maurizio Giannotti🇺🇸 · Alessandro Mirizzi🇮🇹 · Sanjay Reddy🇺🇸

   We perform general relativistic one-dimensional supernova (SN) simulations to identify observable signatures of enhanced axion emission from the pion-induced reaction ${\pi }^{-}+p\to n+a$ inside a newly born protoneutron star (PNS).We focus on the early evolution after the onset of the supernova explosion to predict the temporal and spectral features of the neutrino and axion emission during the first 10 s. Pions are included as explicit new degrees of freedom in hot and dense matter. Their thermal population and their role in axion production are both determined consistently to include effects due to their interactions with nucleons. For a wide range of ambient conditions encountered inside a PNS, we find that the pion-induced axion production dominates over nucleon-nucleon bremsstrahlung processes. By consistently including the role of pions on the dense matter equation of state and on the energy loss, our simulations predict robust discernible features of neutrino and axion emission from a galactic supernova that can be observed in terrestrial detectors. For axion couplings that are compatible with current bounds, we find a significant suppression with time of the neutrino luminosity during the first 10 s. This suggests that current bounds derived from the neutrino signal from SN 1987A can be improved and that future galactic supernovae may provide significantly more stringent constraints.

   hep-phastro-ph.HEPRD(2021)·93 citations
7. 07*

   Pionic depth of the hadron gas after a heavy-ion collision

   Guillermo Gómez Fonfría🇪🇸 · Felipe J. Llanes-Estrada🇪🇸 · Javier Suárez Sucunza🇪🇸 · Juan M. Torres-Rincon🇩🇪

   The final stage of a relativistic heavy-ion collision is a hadron gas. Final-state interactions therein distort the $p_T$ spectrum of particles coming from the phase transition upon cooling the quark-gluon plasma. Using recent state-of-the-art parametrizations of pion interactions we provide theoretical computations of the pionic depth of the gas: how likely is it that a given pion rescatters in it (we find a high probability around $p_T=0.5$ GeV at midrapidity, corresponding to the formation of the $\rho$ resonance), a comparison of the collision and Bjorken expansion rates, and how many pions make it through without interacting as a function of $p_T$. This is in the range 10-24$\%$ and shown in this plot, the main result of the contribution.

   hep-phnucl-thPoS(2022)·1 citation
8. 08*

   Could $M_{T2}$ be a singularity variable?

   Chan Beom Park🇰🇷

   The algebraic singularity method is a framework for analyzing collider events with missing energy. It provides a way to draw out a set of singularity variables that can catch singular features originating from the projection of full phase space onto the observable phase space of measured particle momenta. It is a promising approach applicable to various physics processes with missing energy but still requires more studies for use in practice. Meanwhile, in the double-sided decay topology with an invisible particle on each side, the $M_{T2}$ variable has been known to be a useful collider observable for measuring particle masses from missing energy events or setting signal regions of collider searches. We investigate the relation between the two different types of kinematic variables in double-sided decay topology. We find that the singularity variables contain the $M_{T2}$ variable in many cases, although the former is not a strict superset of the latter.

   hep-phhep-exJHEP(2021)·4 citations
9. 09*

   Cross-fertilising extra gauge boson searches at the LHC

   Jack Y. Araz🇬🇧 · Mariana Frank🇨🇦 · Benjamin Fuks🇫🇷 · Stefano Moretti🇬🇧 · Özer Özdal🇨🇦

   For the purpose of cross-fertilising currently separate experimental approaches, we connect results of LHC analyses attempting to access the properties of additional $W^{\prime }$ and $Z^{\prime }$ bosons from Drell-Yan processes. Under theoretical assumptions linking the two new gauge bosons, we take into account that such possible states of nature are wide enough (in relation to the leptonic mass resolution) for the corresponding signals be significantly affected by interference effects with the background from the Standard Model. The shape of the differential cross section may then no longer be a standard Breit-Wigner distribution, and asymmetry observables would become useful for characterisation (and, possibly, discovery) purposes. Under such conditions we concentrate our analysis on specific widely-studied models: the Sequential Standard Model, a model with an additional $SU(2{)}_L$ gauge symmetry, as well as standard and alternative realisations of the Left-Right Symmetric Model. We show how information gathered in $Z^{\prime }$ boson searches in terms of cross section and/or asymmetry distributions can be used to improve $W^{\prime }$ boson searches in terms of the LHC sensitivity, and {\it vice versa}.

   hep-phJHEP(2021)·7 citations
10. 10*

    The physics of adiabatic particle number in the Schwinger effect

    Anton Ilderton🇬🇧

    The production of electron-positron pairs from light is a famous prediction of quantum electrodynamics. Yet it is often emphasised that the number of produced pairs has no physical meaning until the driving electromagnetic fields are switched off, as otherwise its definition is basis-dependent. The common adiabatic definition, in particular, can predict the `creation' of a number of pairs orders of magnitude larger than the final yield. We show here, by clarifying exactly what is being counted, that the adiabatic number of pairs has an unambiguous and physical interpretation. As a result, and perhaps contrary to expectation, the large numbers of pairs seen at non-asymptotic times become, in principle, physically accessible.

    hep-phhep-thPRD(2022)·49 citations
11. 11*

    Scanning the landscape of axion dark matter detectors: applying gradient descent to experimental design

    J. I. McDonald🇧🇪

    The hunt for dark matter remains one of the principal objectives of modern physics and cosmology. Searches for dark matter in the form of axions are proposed or underway across a range of experimental collaborations. As we look to the next generation of detectors, a natural question to ask is whether there are new experimental designs waiting to be discovered and how we might find them. Here we take a new approach to the experimental design procedure by using gradient descent techniques to search for optimal detector designs. We provide a proof of principle for this technique by searching 1D detectors varying the bulk properties of the detector until the optimal detector design is obtained. Remarkably, we find the detector is capable of out-performing a human designed experiment on which the search was initiated. This opens the door to further gradient descent searches of more complex 2D and 3D designs across a wider variety of materials and boundary geometries of the detector. There is also an opportunity to use more sophisticated gradient descent algorithms to complete a more exhaustive scan of the landscape of designs.

    hep-phhep-exPRD(2022)·6 citations
12. 12*

    Quantifying the Underlying Event: Investigating Angular Dependence of Multiplicity Classes and Transverse-momentum Spectra in High-energy pp Collisions at LHC Energies

    Aditya Nath Mishra🇭🇺 · Gergely Gábor Barnaföldi🇭🇺 · Guy Paić🇲🇽

    We present a study of the transverse momentum spectra and their evolution in function of the position of the azimuthal of the particles associated to the leading particle. Additionally, the behavior of the spherocity distribution in the same azimuthal bins is reported. The studies were made using proton-proton collisions at $\sqrt{s}$ = 13 TeV using PYTHIA8 Monte Carlo event generator. The Multiplicity and midrapidity transverse momentum spectra of charged hadrons have been analyzed in the non-extensive statistical framework. The results on the findings corresponding to the Underlying Event are reported.

    hep-phJ.Phys.G(2023)·6 citations
13. 13*

    $P_{\gamma h}^{\alpha }$: a new variable for $\gamma /\mathrm{h}$ discrimination in large gamma-ray ground arrays

    R. Conceição🇵🇹 · B. S. González🇵🇹 · M. Pimenta🇵🇹 · B. Tomé🇵🇹

    In this letter, a new strategy to enhance the discrimination of high energy gamma rays from the huge charged cosmic rays background in large cosmic rays ground arrays is presented. This strategy is based on the introduction of a new simple variable, $P_{\gamma h}^{\alpha }$, which combines the probability of tagging muons and/or very energetic particles in each single array station. The discrimination power of this new variable, particularly important for and above multi-TeV energies, is illustrated for a few specific examples in the case of a hypothetical water Cherenkov detector cosmic ray array, both in the case of low and high particle stations occupancy. The results are very encouraging and hopefully will be demonstrated in the present and future gamma-ray Observatories.

    hep-phastro-ph.HEhep-exPLB(2022)·7 citations
14. 14*

    Lepton pair production from a hot and dense QCD medium in the presence of an arbitrary magnetic field

    Aritra Das🇮🇳 · Aritra Bandyopadhyay🇨🇳 · Chowdhury Aminul Islam🇨🇳

    In this article, we have explored the very important quantity of lepton pair production from a hot and dense QCD medium in presence of an arbitrary external magnetic field for simultaneous nonzero values of both the parallel (along the direction of the external field) and perpendicular (lying on the transverse plane to the external field) components of the dilepton momentum. As opposed to the zero magnetic field case (the so-called Born rate) or the lowest Landau level approximated rate, where only the annihilation process contributes, here we observe contributions also arising out of the quark and antiquark decay processes. We found the encouraging result of considerable enhancement of lepton pair production in presence of an arbitrary magnetic field. We decompose the total rate into different physical processes and discuss their behaviors for both zero and nonzero baryon density. The whole analysis is then subjected to an effective model treatment, where we have incorporated the magnetic field induced novel effects of magnetic catalysis (MC) and inverse MC (IMC) through a medium dependent scalar coupling, which leads to some further interesting observations.

    hep-phnucl-thPRD(2022)·29 citations
15. 15*

    Charm and beauty in the deconfined plasma from quenched lattice QCD

    Heng-Tong Ding🇨🇳 · Olaf Kaczmarek🇩🇪 · Anna-Lena Lorenz🇩🇪 · Hiroshi Ohno🇯🇵 · Hauke Sandmeyer🇩🇪 · Hai-Tao Shu🇩🇪

    We present continuum extrapolated results of charmonium and bottomonium correlators in the vector channel at several temperatures below and above $T_c$. The continuum extrapolation jointly performed with the interpolations to have physical values of $J/\psi$ and ${\rm Y}$ masses in the confined phase is based on calculations on several large quenched isotropic lattices using clover-improved Wilson valence fermions carrying different quark masses. The extrapolated lattice correlators are confronted with perturbation theory results incorporating resummed thermal effects around the threshold from pNRQCD and vacuum asymptotics above the threshold. An additional transport peak is modelled below the threshold allowing for an estimate of the diffusion coefficients for charm and bottom quarks. We find that charmonium correlators in the vector channel can be well reproduced by perturbative spectral functions above $T_c$ where no resonance peaks for $J/\psi$ are needed at and above 1.1 $T_c$, while for bottomonium correlators a resonance peak for ${\rm Y}$ is still needed up to 1.5 $T_c$. By analyzing the transport contribution to the correlators we find that the drag coefficient of a charm quark is larger than that of a bottom quark.

    ↳ hep-lathep-phnucl-exnucl-thPRD(2021)·16 citations
16. 16*

    The BEST framework for the search for the QCD critical point and the chiral magnetic effect

    Xin An🇺🇸 · Marcus Bluhm🇫🇷 · Lipei Du🇺🇸 · Gerald V. Dunne🇺🇸 · Hannah Elfner🇩🇪 · Charles Gale🇨🇦 · Joaquin Grefa🇺🇸 · Ulrich Heinz🇺🇸 · Anping Huang🇺🇸 · Jamie M. Karthein🇺🇸 · Dmitri E. Kharzeev🇺🇸 · Volker Koch🇺🇸 and 31 other authors

    The Beam Energy Scan Theory (BEST) Collaboration was formed with the goal of providing a theoretical framework for analyzing data from the Beam Energy Scan (BES) program at the relativistic heavy ion collider (RHIC) at Brookhaven National Laboratory. The physics goal of the BES program is the search for a conjectured QCD critical point as well as for manifestations of the chiral magnetic effect. We describe progress that has been made over the previous five years. This includes studies of the equation of state and equilibrium susceptibilities, the development of suitable initial state models, progress in constructing a hydrodynamic framework that includes fluctuations and anomalous transport effects, as well as the development of freezeout prescriptions and hadronic transport models. Finally, we address the challenge of integrating these components into a complete analysis framework. This document describes the collective effort of the BEST Collaboration and its collaborators around the world.

    ↳ nucl-thhep-lathep-phnucl-exNPA(2022)·153 citations
17. 17*

    Stellar Structure and Stability of Charged Interacting Quark Stars and Their Scaling Behaviour

    Chen Zhang🇨🇦 · Michael Gammon🇨🇦 · Robert B. Mann🇨🇦

    We explore the stellar structure and radial stability of charged quark stars composed of interacting quark matter (IQM) in three classes of commonly used charge models. We adopt a general parametrization of IQM equation of state that includes the corrections from perturbative QCD, color superconductivity, and the strange quark mass into one parameter $\lambda$, or one dimensionless parameter $\bar{\lambda }={\lambda }^2/(4B_{\mathrm{eff}})$ after being rescaled with the effective bag constant $B_{\mathrm{eff}}$. We find that increasing charge tends to increase the mass and radius profiles, and enlarges the separation size in mass between the maximum mass point and the point where zero eigenfrequencies ${\omega }_0^2=0$ of the fundamental radial oscillation mode occur. The sign of the separation in central density depends on the charge model; this separation also has a dependence on $\lambda$ such that increasing $\lambda$ (which can occur for either large color superconductivity or small strange quark mass) tends to decrease this separation size for the first and third classes of charge models monotonically. Moreover, for the second and third classes of charge models, we manage to numerically and analytically identify a new kind of stellar structure with a zero central pressure but a finite radius and mass. All the calculations and analysis are performed in a general dimensionless rescaling approach so that the results are independent of explicit values of dimensional parameters.

    ↳ astro-ph.HEgr-qchep-phnucl-thPRD(2021)·21 citations
18. 18*

    Anatomy of Einstein Manifolds

    Jongmin Park🇰🇷 · Jaewon Shin🇰🇷 · Hyun Seok Yang🇰🇷

    An Einstein manifold in four dimensions has some configuration of $SU(2{)}_{+}$ Yang-Mills instantons and $SU(2{)}_{-}$ anti-instantons associated with it. This fact is based on the fundamental theorems that the four-dimensional Lorentz group $Spin(4)$ is a direct product of two groups $SU(2{)}_{\pm }$ and the vector space of two-forms decomposes into the space of self-dual and anti-self-dual two-forms. It explains why the four-dimensional spacetime is special for the stability of Einstein manifolds. We now consider whether such a stability of four-dimensional Einstein manifolds can be lifted to a five-dimensional Einstein manifold. The higher-dimensional embedding of four-manifolds from the viewpoint of gauge theory is similar to the grand unification of Standard Model since the group $SO(4)\cong Spin(4)/{\mathbb{Z}}_2=SU(2{)}_{+}\otimes SU(2{)}_{-}/{\mathbb{Z}}_2$ must be embedded into the simple group $SO(5)=Sp(2)/{\mathbb{Z}}_2$. Our group-theoretic approach reveals the anatomy of Riemannian manifolds quite similar to the quark model of hadrons in which two independent Yang-Mills instantons represent a substructure of Einstein manifolds.

    ↳ hep-thgr-qchep-phmath-ph+1PRD(2022)·7 citations
19. 19*

    Vacuum instability due to the creation of neutral Fermion with anomalous magnetic moment by magnetic-field inhomogeneities

    T. C. Adorno🇨🇳 · Zi-Wang He🇨🇳 · S. P. Gavrilov🇷🇺 · D. M. Gitman🇷🇺

    We study neutral Fermions pair creation with anomalous magnetic moment from the vacuum by time-independent magnetic-field inhomogeneity as an external background. We show that the problem is technically reduced to the problem of charged-particle creation by an electric step, for which the nonperturbative formulation of strong-field QED is used. We consider a magnetic step given by an analytic function and whose inhomogeneity may vary from a "gradual" to a "sharp" field configuration. We obtain corresponding exact solutions of the Dirac-Pauli equation with this field and calculate pertinent quantities characterizing vacuum instability, such as the differential mean number and flux density of pairs created from the vacuum, vacuum fluxes of energy and magnetic moment. We show that the vacuum flux in one direction is formed from fluxes of particles and antiparticles of equal intensity and with the same magnetic moments parallel to the external field. Backreaction to the vacuum fluxes leads to a smoothing of the magnetic-field inhomogeneity. We also estimate critical magnetic field intensities, near which the phenomenon could be observed.

    ↳ hep-thhep-phJHEP(2021)·10 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.