Wed·Nov 6, 2019Wednesday·November 6, 2019

1. 01*

   On the effective theory of neutrino-electron and neutrino-quark interactions

   Richard J. Hill🇺🇸 · Oleksandr Tomalak🇺🇸

   We determine the four Fermi effective theory of neutrino interactions within the Standard Model including one-loop electroweak radiative corrections, in combination with the measured muon lifetime and precision electroweak data. Including two-loop matching and three-loop running corrections, we determine lepton coefficients accounting for all large logarithms through relative order $\mathcal{O}(\alpha {\alpha }_s)$ and quark coefficients accounting for all large logarithms through $\mathcal{O}(\alpha )$. We present four-fermion coefficients valid in $n_f=3$ and $n_f=4$ flavor quark theories, as well as in the extreme low-energy limit. We relate the coefficients in this limit to neutrino charge radii governing matter effects via forward neutrino scattering on charged particles.

   hep-phhep-exnucl-exnucl-thPLB(2020)·39 citations
2. 02*

   Spin-one dark matter and gamma ray signals from the galactic center

   H. Hernandez-Arellano🇲🇽 · M. Napsuciale🇲🇽 · S. Rodriguez🇲🇽

   In this work we study the possibility that the gamma ray excess (GRE) at the Milky Way galactic center come from the annihilation of dark matter with a $(1,0)\oplus (0,1)$ space-time structure (spin-one dark matter, SODM). We calculate the production of prompt photons from initial state radiation, internal bremsstrahlung, final state radiation including the emission from the decay products of the $\mu ,\tau$ or hadronization of quarks. Next we study the delayed photon emission from the inverse Compton scattering (ICS) of electrons (produced directly or in the prompt decay of $\mu ,\tau$ leptons or in the hadronization of quarks produced in the annihilation of SODM) with the cosmic microwave background or starlight. All these mechanisms yield significant contributions only for Higgs resonant exchange, i.e. for $M\approx M_H/2$, and the results depend on the Higgs scalar coupling to SODM, $g_s$. The dominant mechanism at the GRE bump is the prompt photon production in the hadronization of $b$ quarks produced in $\bar{D}D\to \bar{b}b$, whereas the delayed photon emission from the ICS of electrons coming from the hadronization of $b$ quarks produced in the same reaction dominates at low energies ($\omega <0.3GeV$) and prompt photons from $c$ and $\tau$, as well as from internal bremsstrahlung, yield competitive contributions at the end point of the spectrum ($\omega \ge 30GeV$). Taking into account all these contributions, our results for photons produced in the annihilation of SODM are in good agreement with the GRE data for $g_s\in [0.98,1.01]\times 10^{-3}$ and $M\in [62.470,62.505]GeV$.

   hep-phJHEP(2020)·8 citations
3. 03*

   Macro-coherent radiative emission of neutrino pair between parity-even atomic states

   M. Tashiro🇯🇵 · B. P. Das🇯🇵 · J. Ekman🇸🇪 · P. Jonsson🇸🇪 · N. Sasao🇯🇵 · M. Yoshimura🇯🇵

   A new scheme to determine the neutrino mass matrix is proposed using atomic de-excitation between two states of a few eV energy spacing. The determination of the smallest neutrino mass of the order of 1 meV and neutrino mass type, Majorana or Dirac, becomes possible, if one can coherently excite more than 1 gram of atoms using two lasers.

   hep-phEPJC(2019)·6 citations
4. 04*

   Multiplicity per rapidity in Carruthers and hadron resonance gas approaches

   Abdel Nasser Tawfik (Nile U., ECTP)🇪🇬 · Mahmoud Hanafy (Benha U. and WLCAPP, Cairo)🇪🇬 · Werner Scheinast (LHEP JINR, Dubna)🇷🇺

   The multiplicity per rapidity of the well-identified particles ${\pi }^{-}$, ${\pi }^{+}$, $k^{-}$, $k^{+}$, $\bar{p}$, $p$, and $p-\bar{p}$ measured in different high-energy experiments, at energies ranging from $6.3$ to $5500$GeV, are successfully compared with the Cosmic Ray Monte Carlo (CRMC) event generator. For these rapidity distributions, we introduce a theoretical approach based on fluctuations and correlations (Carruthers) and another one based on statistical thermal assumptions (hadron resonance gas model). Both approaches are fitted to the two sets of results deduced from experiments and simulations. We found that the Carruthers approach reproduces well the full range of multiplicity per rapidity for all produced particles, at the various energies, while the HRG approach fairly describes the results within a narrower rapidity-range. While the Carruthers approach seems to match well with the Gaussian normal distribution, ingredients such as flow and interactions should be first incorporated in the HRG approach.

   hep-phIndian J.Phys.(2022)·4 citations
5. 05*

   Initial, effective, and kinetic freeze-out temperatures from transverse momentum spectra in high energy proton(deuteron)-nucleus and nucleus-nucleus collisions

   Muhammad Waqas🇨🇳 · Fu-Hu Liu🇨🇳

   The transverse momentum spectra of charged particles produced in proton(deuteron)-nucleus and nucleus-nucleus collisions at high energies are analyzed by the Hagedorn thermal model and the standard distribution in terms of multi-component. The experimental data measured in central and peripheral gold-gold (Au-Au) and deuteron-gold ($d$-Au) collisions by the PHENIX Collaboration at the Relativistic Heavy Ion Collider (RHIC), as well as in central and peripheral lead-lead (Pb-Pb) and proton-lead ($p$-Pb) collisions by the ALICE Collaboration at the Large Hadron Collider (LHC) are fitted by the two models. The initial, effective, and kinetic freeze-out temperatures are then extracted from the fitting to the transverse momentum spectra. It is shown that the initial temperature is larger than the effective temperature, and the effective temperature is larger than the kinetic freeze-out temperature. The three types of temperatures in central collisions are comparable with those in peripheral collisions, and those at the LHC are comparable with those at the RHIC.

   hep-phhep-exnucl-exnucl-thEur.Phys.J.Plus(2020)·44 citations
6. 06*

   Interpretability Study on Deep Learning for Jet Physics at the Large Hadron Collider

   Taoli Cheng🇨🇦

   Using deep neural networks for identifying physics objects at the Large Hadron Collider (LHC) has become a powerful alternative approach in recent years. After successful training of deep neural networks, examining the trained networks not only helps us understand the behaviour of neural networks, but also helps improve the performance of deep learning models through proper interpretation. We take jet tagging problem at the LHC as an example, using recursive neural networks as a starting point, aim at a thorough understanding of the behaviour of the physics-oriented DNNs and the information encoded in the embedding space. We make a comparative study on a series of different jet tagging tasks dominated by different underlying physics. Interesting observations on the latent space are obtained.

   hep-phcs.LGhep-exstat.ML4 citations
7. 07*

   Searching for the odderon in $pp\to pp{K}^{+}{K}^{-}$ and $pp\to pp{\mu }^{+}{\mu }^{-}$ reactions in the $\varphi (1020)$ resonance region at the LHC

   Piotr Lebiedowicz🇵🇱 · Otto Nachtmann🇩🇪 · Antoni Szczurek🇵🇱

   We explore the possibility of observing odderon exchange in the $pp\to pp{K}^{+}{K}^{-}$ and $pp\to pp{\mu }^{+}{\mu }^{-}$ reactions at the LHC. We consider the central exclusive production (CEP) of the $\varphi (1020)$ resonance decaying into $K^{+}{K}^{-}$ and ${\mu }^{+}{\mu }^{-}$. We compare the purely diffractive contribution (odderon-pomeron fusion) to the photoproduction contribution (photon-pomeron fusion). The theoretical results are calculated within the tensor-pomeron and vector-odderon model for soft reactions. We include absorptive corrections at the amplitude level. In order to fix the coupling constants for the photon-pomeron fusion contribution we discuss the reactions $\gamma p\to \omega p$ and $\gamma p\to \varphi p$ including $\varphi$-$\omega$ mixing. We compare our results for these reactions with the available data, especially those from HERA. Our coupling constants for the pomeron-odderon-$\varphi$ vertex are taken from an analysis of the WA102 data for the $pp\to pp\varphi$ reaction. We show that the odderon-exchange contribution significantly improves the description of the $pp$ azimuthal correlations and the $d{P}_t$ "glueball-filter variable" dependence of $\varphi$ CEP measured by WA102. To describe the low-energy data more accurately we consider also subleading processes with reggeized vector-meson exchanges. However, they do not play a significant role at the LHC. We present predictions for two possible types of measurements: at midrapidity and with forward measurement of protons (relevant for ATLAS-ALFA or CMS-TOTEM), and at forward rapidities and without measurement of protons (relevant for LHCb). We discuss the influence of experimental cuts on the integrated cross sections and on various differential distributions. With the corresponding LHC data one should be able to get a decisive answer concerning the presence of an odderon-pomeron fusion contribution in single $\varphi$ CEP.

   hep-phPRD(2020)·23 citations
8. 08*

   Singularity Variables for Missing Energy Event Kinematics

   Konstantin T. Matchev🇺🇸 · Prasanth Shyamsundar🇺🇸

   We discuss singularity variables which are properly suited for analyzing the kinematics of events with missing transverse energy at the LHC. We consider six of the simplest event topologies encountered in studies of leptonic W-bosons and top quarks, as well as in SUSY-like searches for new physics with dark matter particles. In each case, we illustrate the general prescription for finding the relevant singularity variable, which in turn helps delineate the visible parameter subspace on which the singularities are located. Our results can be used in two different ways - first, as a guide for targeting the signal-rich regions of parameter space during the stage of discovery, and second, as a sensitive focus point method for measuring the particle mass spectrum after the initial discovery.

   hep-phhep-exJHEP(2020)·12 citations
9. 09*

   Flavor structure of magnetized $T^2/{\mathbb{Z}}_2$ blow-up models

   Tatsuo Kobayashi🇯🇵 · Hajime Otsuka🇯🇵 · Hikaru Uchida🇯🇵

   We discuss the flavor structure in a resolutions of magnetized $T^2/{\mathbb{Z}}_2$ orbifold models. The flavor structure of Yukawa couplings among chiral zero-modes is sensitive to radii of the resolved fixed points of $T^2/{\mathbb{Z}}_2$ orbifold. We show in concrete models that the realistic mass hierarchy and mixing angles of the quark sector can be realized at certain values of blow-up radii, where the number of parameters in the blow-up model can be smaller than toroidal orbifold one.

   hep-phhep-thJHEP(2020)·11 citations
10. 10*

    Nucleon quasi-Parton Distributions in the large N${}_c$ limit

    Hyeon-Dong Son🇩🇪 · Asli Tandogan🇩🇪 · Maxim V. Polyakov🇷🇺

    In this letter, we investigate the nucleon quasi-parton distribution functions in the chiral quark soliton model. We derive a set of sum-rules depending on the velocity of the nucleon and on the Dirac matrix defining the distribution functions. We present numerical results for the isosinglet unpolarized distribution, in which we find that the anti-quark distribution breaks the positivity condition at nucleon velocities $v\approx 0.99(P_N\approx 7.0M_N)$ and smaller. We found that, for the isosinglet unpolarized case, a large nucleon momentum is required for the quasi-parton distribution to get close enough to the usual parton distribution function.

    hep-phhep-latPLB(2020)·18 citations
11. 11*

    A fragmentation-based study of heavy quark production

    Giovanni Ridolfi🇮🇹 · Maria Ubiali🇬🇧 · Marco Zaro🇳🇱

    Processes involving heavy quarks are a crucial component of the LHC physics program, both by themselves and as backgrounds for Higgs physics and new physics searches. In this work, we critically reconsider the validity of the widely-adopted approximation in which heavy quarks are generated at the matrix-element level, with special emphasis on the impact of the collinear logarithms associated with final-state heavy quark and gluon splittings. Our study, based on a perturbative fragmentation-function approach, explicitly shows that neglecting the resummation of collinear logarithms may yield inaccurate predictions, in particular when observables exclusive in the heavy quark degrees of freedom are considered. Our findings motivate the use of schemes which encompass the resummation of final-state collinear logarithms.

    hep-phJHEP(2020)·25 citations
12. 12*

    A novel test of Lorentz violation in the photon sector with an LC circuit

    P. C. Malta🇧🇷

    In the presence of an external magnetic field, the Carroll-Field-Jackiw term introduces a displacement current proportional to the Lorentz-violating background that induces a time-dependent magnetic field. Axion-like particles or hidden photons could generate an analogous signal, potentially detectable with the set-up suggested by Sikivie, Tanner and Sullivan - a sensitive magnetometer coupled to a superconducting LC circuit. We show that a similar set-up, but with an externally driven pick-up loop whose area varies harmonically at $\sim$ Hz, can be used to probe the spatial components of the Lorentz-violating background to the level of $\lesssim 10^{-31}$ GeV. This is eight orders of magnitude more sensitive than previous laboratory-based limits.

    hep-phhep-thPRD(2020)·1 citation
13. 13*

    Deep Learning Jet Substructure from Two-Particle Correlation

    Kai-Feng Chen🇹🇼 · Yang-Ting Chien🇺🇸

    Deciphering the complex information contained in jets produced in collider events requires a physical organization of the jet data. We introduce two-particle correlations (2PCs) by pairing individual particles as the initial jet representation from which a probabilistic model can be built. Particle momenta, as well as particle types and vertex information are included in the correlation. A novel, two-particle correlation neural network (2PCNN) architecture is constructed by combining neural network based filters on 2PCs and a deep neural network for capturing jet kinematic information. The 2PCNN is applied to boosted boson and heavy flavor tagging, and it achieves excellent performance by comparing to models based on telescoping deconstruction. Major correlation pairs exploited in the trained models are also identified, which shed light on the physical significance of certain jet substructure.

    hep-phhep-exnucl-exPRD(2020)·7 citations
14. 14*

    Sequentially loop supressed fermion masses from a unique discrete symmetry

    Carolina Arbeláez🇨🇱 · A. E. Cárcamo Hernández🇨🇱 · Ricardo Cepedello🇪🇸 · Sergey Kovalenko🇨🇱 · Ivan Schmidt🇨🇱

    We propose a systematic and renormalizable sequential loop suppression mechanism to generate the hierarchy of the Standard Model fermion masses from one discrete symmetry. The discrete symmetry is sequentially softly broken in order to generate one-loop level masses for the bottom, charm, tau and muon leptons and two-loop level masses for the lightest Standard Model charged fermions. The tiny masses for the light active neutrinos are produced from radiative type-I seesaw mechanism, where the Dirac mass terms are effectively generated at two-loop level.

    hep-phJHEP(2020)·11 citations
15. 15*

    Hyperons in thermal QCD from the lattice

    Gert Aarts🇬🇧 · Chris Allton🇬🇧 · Davide de Boni🇬🇧 · Jonas Glesaaen🇬🇧 · Simon Hands🇬🇧 · Benjamin Jäger🇩🇰 · Jon-Ivar Skullerud🇮🇪

    We study the spectrum of light baryons and hyperons as a function of temperature using lattice gauge theory methods. We find that masses of positive parity states are temperature independent, within errors, in the hadronic phase. The negative parity states decrease in mass as the temperature increases. Above the deconfining temperature, lattice correlators and spectral functions show a degeneracy between parity sectors, i.e. parity doubling. We apply our findings to an in-medium Hadron Resonance Gas model. The techniques used in this study include direct analysis of the hadronic correlation functions, conventional fitting procedures, and the Maximum Entropy Method.

    ↳ hep-lathep-phSpringer Proc.Phys.(2020)·1 citation
16. 16*

    Motivic Galois coaction and one-loop Feynman graphs

    Matija Tapušković🇬🇧

    Following the work of Brown, we can canonically associate a family of motivic periods -- called the motivic Feynman amplitude -- to any convergent Feynman integral, viewed as a function of the kinematic variables. The motivic Galois theory of motivic Feynman amplitudes provides an organizing principle, as well as strong constraints, on the space of amplitudes in general, via Brown's "small graphs principle". This serves as motivation for explicitly computing the motivic Galois action, or, dually, the coaction of the Hopf algebra of functions on the motivic Galois group. In this paper, we study the motivic Galois coaction on the motivic Feynman amplitudes associated to one-loop Feynman graphs. We study the associated variations of mixed Hodge structures, and provide an explicit formula for the coaction on the four-edge cycle graph -- the box graph -- with non-vanishing generic kinematics, which leads to a formula for all one-loop graphs with non-vanishing generic kinematics in four-dimensional space-time. We also show how one computes the coaction in some degenerate configurations -- when defining the motive of the graph requires blowing up the underlying family of varieties -- on the example of the three-edge cycle graph.

    ↳ math.AGhep-phhep-thmath-ph+1Commun.Num.Theor.Phys.(2021)·14 citations
17. 17*

    Polarized primordial gravitational waves in the ghost-free parity-violating gravity

    Jin Qiao🇨🇳 · Tao Zhu🇨🇳 · Wen Zhao🇨🇳 · Anzhong Wang🇺🇸

    The tests of parity symmetry in the gravitational interaction is an attractive issue in the gravitational-wave astronomy. In the general theories of gravity with parity violation, one of the fundamental results is that the primordial gravitational waves (PGWs) produced during the slow-roll inflation is circularly polarized. In this article, we investigate the polarization of PGWs in the recently proposed ghost-free parity-violating gravity, which generalizes the Chern-Simons gravity by including the higher derivatives of the coupling scalar field. For this purpose, we first construct the approximate analytical solution to the mode function of the PGWs during the slow-roll inflation by using the uniform asymptotic approximation. With the approximate solution, we calculate explicitly the power spectrum and the corresponding circular polarization of the PGWs analytically, and find that the contributions of the higher derivatives of the coupling scalar field to the circular polarization is of the same order of magnitude as that of Chern-Simons gravity. The degree of circular polarization of PGWs is suppressed by the energy scale of parity violation in gravity, which is hardly detected on the basis solely of two-point statistics from future cosmic microwave background data.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2020)·67 citations
18. 18*

    Scalarization of asymptotically Anti-de Sitter black holes with applications to holographic phase transitions

    Yves Brihaye🇧🇪 · Betti Hartmann🇧🇷 · Nathália Pio Aprile🇧🇷 · Jon Urrestilla🇪🇸

    We study the spontaneous scalarization of spherically symmetric, static and asymptotically Anti-de Sitter (aAdS) black holes in a scalar-tensor gravity model with non-mininal coupling of the form ${\varphi }^2\left(\alpha \mathcal{R}+\gamma \mathcal{G}\right)$, where $\alpha$ and $\gamma$ are constants, while $\mathcal{R}$ and $\mathcal{G}$ are the Ricci scalar and Gauss-Bonnet term, respectively. Since these terms act as an effective ``mass'' for the scalar field, non-trivial values of the scalar field in the black hole space-time are possible for {\it a priori} vanishing scalar field mass. In particular, we demonstrate that the scalarization of an aAdS black hole requires the curvature invariant $-\left(\alpha \mathcal{R}+\gamma \mathcal{G}\right)$ to drop below the Breitenlohner-Freedman bound close to the black hole horizon, while it asymptotes to a value well above the bound. The dimension of the dual operator on the AdS boundary depends on the parameters $\alpha$ and $\gamma$ and we demonstrate that -- for fixed operator dimension -- the expectation value of this dual operator increases with decreasing temperature of the black hole, i.e. of the dual field theory. When taking backreaction of the space-time into account, we find that the scalarization of the black hole is the dual description of a phase transition in a strongly coupled quantum system, i.e. corresponds to a holographic phase transition. A possible application are liquid-gas quantum phase transitions, e.g. in ${}^4$He. Finally, we demonstrate that extremal black holes with $Ad{S}_2\times S^2$ near-horizon geometry {\it cannot support regular scalar fields on the horizon} in the scalar-tensor model studied here.

    ↳ gr-qchep-phhep-thPRD(2020)·36 citations
19. 19*

    Spacetime Fluctuations in AdS/CFT

    Erik Verlinde🇳🇱 · Kathryn M. Zurek🇺🇸

    We compute fluctuations in the modular energy of the vacuum associated with a Rindler-wedge in AdS spacetime in the context of AdS/CFT. We discuss the possible effect of these energy fluctuations on the spacetime geometry, and on the traversal time of a light beam propagating from the boundary to the bulk and back.

    ↳ hep-thgr-qchep-phJHEP(2020)·87 citations
20. 20*

    Exploring S-Wave Threshold Effects in QCD: A Heavy-Light Approach

    Estia Eichten🇺🇸 · Ciaran Hughes🇺🇸

    QCD exhibits complex dynamics near S-wave two-body thresholds. For light mesons, we see this in the failure of quark models to explain the $f_0(500)$ and $K_0^{\ast }(700)$ masses. For charmonium, an unexpected $X(3872)$ state appears at the open charm threshold. In heavy-light systems, analogous threshold effects appear for the lowest $J^P=0^{+}$ and $1^{+}$ states in the $D_s$ and $B_s$ systems. Here we describe how lattice QCD can be used to understand these threshold dynamics by smoothly varying the strange-quark mass when studying the heavy-light systems. Small perturbations around the physical strange quark mass are used so to always remain near the physical QCD dynamics. This calculation is a straightforward extension of those already in the literature and can be undertaken by multiple lattice QCD collaborations with minimal computational cost.

    ↳ hep-lathep-phPLB(2020)·3 citations
21. 21*

    Diffusion of heavy quarks in the early stage of high-energy nuclear collisions at energies available at the BNL Relativistic Heavy Ion Collider and at the CERN Large Hadron Collider

    J. H. Liu🇨🇳 · S. Plumari🇮🇹 · S. K. Das🇮🇳 · V. Greco🇮🇹 · M. Ruggieri🇨🇳

    We study the diffusion of charm and beauty in the early stage of high energy nuclear collisions at RHIC and LHC energies, considering the interaction of these heavy quarks with the evolving Glasma by means of the Wong equations. In comparison with previous works, we add the longitudinal expansion as well as we estimate the effect of energy loss due to gluon radiation. We find that heavy quarks diffuse in the strong transverse color fields in the very early stage (0.2-0.3 fm/c) and this leads to a suppression at low $p_T$ and enhancement at intermediate low $p_T$. The shape of the observed nuclear suppression factor obtained within our calculations is in qualitative agreement with the experimental results of the same quantity for $D-$mesons in proton-nucleus collisions. We compute the nuclear suppression factor in nucleus-nucleus collisions as well, for both charm and beauty, finding a substantial impact of the evolving Glasma phase on these, suggesting that initialization of heavy quarks spectra in the quark-gluon plasma phase should not neglect the early evolution in the strong gluon fields.

    ↳ nucl-thhep-exhep-phnucl-exPRC(2020)·40 citations
22. 22*

    Meson spectrum in SU(N) gauge theories with quarks in higher representations: A check of Casimir scaling hypothesis

    F. Buisseret🇧🇪 · C. Semay🇧🇪

    Gauge theories with gauge group $SU(N)$ and quarks belonging to arbitrary representations of $SU(N)$ form a rich landscape of QCD-like theories, whose study can shed new light on the properties of confinement. Four cases are particularly worth of interest: quarks in the fundamental representation, quarks in the 2-indice (anti)symmetric representation and quarks in the adjoint representation. The last three corresponding QCD-like theories are equivalent at large-$N$ for bosonic observables: It is the orientifold equivalence. The behavior of the lightest vector meson mass versus $N$ has been studied in quenched lattice QCD in the chiral limit in these theories. We show that the observed behaviors are compatible with a string tension proportional to the quadratic Casimir of $SU(N)$ in the quark color representation, $\text{i.e.}$ with the Casimir scaling hypothesis. The large-$N$ limit of some excited meson masses computed in quenched lattice QCD with quarks in the fundamental representation is also shown to be compatible with QCD string's well-known signature: Regge trajectories.

    ↳ hep-lathep-phhep-thResults Phys.(2020)·2 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.