Thu·Sep 10, 2020Thursday·September 10, 2020

1. 01*

   Empirical Consequences of Emergent Mass

   Craig D. Roberts🇨🇳

   The Lagrangian that defines quantum chromodynamics (QCD), the strong interaction piece of the Standard Model, appears very simple. Nevertheless, it is responsible for an astonishing array of high-level phenomena with enormous apparent complexity, e.g., the existence, number and structure of atomic nuclei. The source of all these things can be traced to emergent mass, which might itself be QCD's self-stabilising mechanism. A background to this perspective is provided, presenting, inter alia, a discussion of the gluon mass and QCD's process-independent effective charge and highlighting an array of observable expressions of emergent mass, ranging from its manifestations in pion parton distributions to those in nucleon electromagnetic form factors.

   hep-phhep-exhep-latnucl-ex+1Symmetry(2020)·94 citations
2. 02*

   Asymptotic analysis of the Boltzmann equation for dark matter relic abundance

   Logan A. Morrison🇺🇸 · Hiren H. Patel🇺🇸 · Jaryd F. Ulbricht🇺🇸

   A solution to the Boltzmann equation governing the thermal relic abundance of cold dark matter is constructed by matched asymptotic approximations. The approximation of the relic density is an asymptotic series valid when the abundance does not deviate significantly from its equilibrium value until small temperatures. Resonance and threshold effects are taken into account at leading order and found to be negligible unless the annihilation cross section is negligible at threshold. Comparisons are made to previously attempted constructions and to the freeze out approximation commonly employed in the literature. Extensions to higher order matching is outlined, and implications for solving related systems are discussed. We compare our results to a numerical determination of the relic abundance using a benchmark model and find a fantastic agreement. The method developed also serves as a solution to a wide class of problems containing an infinite order turning point.

   hep-phhep-thJCAP(2021)·2 citations
3. 03*

   Comparison of results for the electromagnetic form factors of the proton at low $Q^2$

   Evangelos Matsinos

   The goal in this work is the comparison of five parameterisations of the Sachs form factors of the proton $G_E^p$ (electric) and $G_M^p$ (magnetic) at low $4$-momentum transfer $Q^2$. It will be shown that a simple model, based on two dipoles which admit as parameters the rms electric charge radius $r_{E;p}$ and the rms magnetic radius $r_{M;p}$ of the proton, suffices for the purposes of the phase-shift analyses (PSAs) of the low-energy pion-nucleon ($\pi N$) data. The replacement of the electromagnetic form factors, currently used in the ETH model of the $\pi N$ interaction, by the parameterisation of this work will enable the removal from the PSAs of this research programme of the largest part of the dependence on extraneous sources.

   hep-phnucl-th0 citations
4. 04*

   Super heavy particle production in high energy heavy ion collision

   A. B. Kurepin (Institute for Nuclear Research, RAS, Moscow)🇷🇺

   The estimate based on the parton model is made on the rate of production of Super Heavy Particle ( SHP ) in subthreshold collision of heavy ions at LHC. For the one month run of lead-lead collision the yield of 16 TeV particle is of the order of 70 per year.

   hep-phJ.Mod.Phys.(2021)·2 citations
5. 05*

   Evidence of the four-quark nature of $f_0(980)$ and $f_0(500)$

   N.N. Achasov🇷🇺 · J.V. Bennett🇺🇸 · A.V. Kiselev🇷🇺 · E.A. Kozyrev🇷🇺 · G.N. Shestakov🇷🇺

   There exists a great deal of concrete evidence in favor of the exotic four-quark nature of light scalars. At the same time, the further expansion of the area of the $q^2{\bar{q}}^2$ model validity for light scalars on ever new processes seems extremely interesting and important. We analyze the BESIII data on the decay $J/\psi \to \gamma {\pi }^0{\pi }^0$ and show that the results of this high-statistics experiment can be interpreted in favor of the four-quark nature of light scalar mesons $f_0(980)$ and $f_0(500)$.

   hep-phhep-exnucl-thPRD(2021)·34 citations
6. 06*

   Spectral functions from the real-time functional renormalization group

   Sven Huelsmann🇩🇪 · Soeren Schlichting🇩🇪 · Philipp Scior🇩🇪

   We employ the functional renormalization group approach formulated on the Schwinger-Keldysh contour to calculate real-time correlation functions in scalar field theories. We provide a detailed description of the formalism, discuss suitable truncation schemes for real-time calculations as well as the numerical procedure to self-consistently solve the flow equations for the spectral function. Subsequently, we discuss the relations to other perturbative and non-perturbative approaches to calculate spectral functions, and present a detailed comparison and benchmark in $d=0+1$ dimensions.

   hep-phhep-thnucl-thPRD(2020)·35 citations
7. 07*

   Light-front holographic $\rho$-meson distributions in the momentum space

   Satvir Kaur🇮🇳 · Chandan Mondal🇨🇳 · Harleen Dahiya🇮🇳

   We present the leading-twist quark transverse momentum-dependent parton distribution functions (TMDs) for the spin-1 target, such as the $\rho$-meson, in the light-front framework. Specifically, we predict the TMDs in the light-front holographic model and compare with the light-front quark model predictions. We obtain the TMDs using the overlap of the light-front wave functions. We evaluate the ${\mathbf{k}}_{\perp }$ moments upto second order and compare with the available theoretical predictions. Further, we analyze the leading-twist parton distribution functions (PDFs) of the $\rho$-meson in the light-front holographic model which are found to be in accord with the Nambu-Jona-Lasinio (NJL) model and the light-front quark model predictions. We further study the QCD evolution of the PDFs. The positivity bounds on the TMDs and the PDFs are also discussed. We also present the quark spin densities in the transverse momentum plane for different polarization configurations of the quark and the $\rho$-meson target.

   hep-phJHEP(2021)·25 citations
8. 08*

   New scenario for aligned Higgs couplings originated from the twisted custodial symmetry at high energies

   Masashi Aiko🇯🇵 · Shinya Kanemura🇯🇵

   We investigate a new scenario of the two Higgs doublet model, where the current experimental data for the electroweak rho parameter and those for the Higgs boson couplings can be simultaneously explained. In this scenario, the two Higgs doublet model is supposed to be a low energy effective theory up to a high energy scale $\Lambda$, above which a fundamental theory should appear. It is assumed that the Higgs potential respects a global symmetry at $\Lambda$ (the twisted custodial symmetry), which is to be given as a consequence of the global symmetry structure of the fundamental theory above $\Lambda$. By the analysis using one-loop renormalization group equations, the above experimental data can be explained in a natural way even when the masses of the extra Higgs bosons are near the electroweak scale. We also discuss the predictions on the mass spectrum of the additional Higgs bosons and also those on coupling constants of the standard-model-like Higgs boson, which make it possible to test this scenario at current and future collider experiments.

   hep-phhep-exJHEP(2021)·20 citations
9. 09*

   Baryogenesis through baryon capture by black holes

   A. D. Dolgov🇷🇺 · N. A. Pozdnyakov🇷🇺

   A novel mechanism of cosmological baryogenesis through baryon capture by primordial black holes is suggested. In contrast to the conventional scenarios it does not demand non-conservation of baryonic number in particle physics and can proceed in thermal equilibrium. For implementation of this mechanism a heavy superweakly interacting particle a with non-zero baryon number is necessary.

   hep-phastro-ph.HE8 citations
10. 10*

    The molecular nature of some exotic hadrons

    A. Ramos🇪🇸 · A. Feijoo🇨🇿 · Q. Llorens🇪🇸 · G. Montaña🇪🇸

    The exciting discovery by LHCb of the $P_c(4312{)}^{+}$ and $P_c(4450{)}^{+}$ pentaquarks, or the suggestion of a tetraquark nature for the $Z_c(3900)$ state seen at BESIII and Belle, have triggered a lot of activity in the field of hadron physics, with new experiments planned for searching other exotic mesons and baryons, and many theoretical developments trying to disentangle the true multiquark nature from their possible molecular origin. After a brief review of the present status of these searches, this paper focusses on recently seen or yet to be discovered exotic heavy baryons that may emerge from a conveniently unitarized meson-baryon interaction model in coupled channels. In particular, we will show how interferences between the different coupled-channel amplitudes of the model may reveal the existence of a $N^{\ast }$ resonance around 2 GeV having a meson-baryon quasi-bound state nature. We also discuss the possible interpretation of some of the ${\Omega }_c$ states recently discovered at LHCb as being hadron molecules. The model also predicts the existence of doubly-charmed quasibound meson-baryon ${\Xi }_{cc}$ states, which would be excited states of the ground-state ${\Xi }_{cc}(3621)$ MeV, whose mass has only been recently established. Extensions of these results to the bottom sector will also be presented.

    hep-phnucl-thFew Body Syst.(2020)·12 citations
11. 11*

    Interpretation of structure in the di-$J/\psi$ spectrum

    Marek Karliner🇮🇱 · Jonathan L. Rosner🇺🇸

    Structure in the di-$J/\psi$ mass spectrum observed by the LHCb experiment around 6.9 and 7.2 GeV is interpreted in terms of $J^{PC}=0^{++}$ and $2^{++}$ resonances between a $cc$ diquark and a $\bar{c}\bar{c}$ antidiquark, using a recently confirmed string-junction picture to calculate tetraquark masses. The main peak around 6.9 GeV is likely dominated by the $0^{++}(2S)$ state, a radial excitation of the $cc$-$\bar{c}\bar{c}$ tetraquark, which we predict at $6.871\pm 0.025$ GeV. The dip around 6.75 GeV is ascribed to the opening of the \Swave\ di-${\chi }_{c0}$ channel, while the dip around 7.2 GeV could be correlated with the opening of the di-${\eta }_c(2S)$ or ${\Xi }_{cc}{\bar{\Xi }}_{cc}$ channel. The low-mass part of the di-$J/\psi$ structure appears to require a broad resonance consistent with a predicted $2^{++}(1S)$ state with invariant mass around $M_{\mathrm{inv}}=6400$ MeV. Implications for $bb\bar{b}\bar{b}$ tetraquarks are discussed.

    hep-phPRD(2020)·107 citations
12. 12*

    Flipped Quartification and a composite $b$-quark

    James B. Dent🇺🇸 · Thomas W. Kephart🇺🇸 · Heinrich Päs🇩🇪 · Thomas J. Weiler🇺🇸

    An alternative "flipped" version of the quartification model is obtained by rearrangement of the particle assignments. The model has two standard (trinification) families and one flipped quartification family. An interesting phenomenological implication is that the model allows for a composite $b$-quark.

    hep-ph2 citations
13. 13*

    Stellar cooling, inelastic dark matter, and XENON

    Wai-Yee Keung🇺🇸 · Danny Marfatia🇺🇸 · Po-Yan Tseng🇰🇷

    We consider a novel scenario of dark photon-mediated inelastic dark matter to explain the white dwarf cooling excess suggested by its luminosity function, and the excess in electron recoil events at XENON1T. In the Sun, the dark photon $A^{\prime }$ is produced mainly via thermal processes, and the heavier dark matter ${\chi }_2$ is produced by the scattering of halo dark matter ${\chi }_1$ with electrons. The XENON1T signal arises primarily by solar $A^{\prime }$ scattering, and $A^{\prime }$ emission by white dwarfs accommodates the extra cooling while maintaining consistency with other stellar cooling observations. A tritium component in the XENON1T detector is also required. We show for parameters that explain the XENON1T data, but not the white dwarf cooling anomaly, that a second signal peak may be buried in the XENON1T data and revealable at XENONnT. However, the parameters that give the double peak in the spectrum are incompatible with constraints from horizontal branch stars.

    hep-phastro-ph.COastro-ph.SRhep-exJHEAp(2021)·9 citations
14. 14*

    Factorization at Subleading Power, Sudakov Resummation and Endpoint Divergences in Soft-Collinear Effective Theory

    Ze Long Liu🇺🇸 · Bianka Mecaj🇩🇪 · Matthias Neubert🇩🇪 · Xing Wang🇩🇪

    Starting from the first renormalized factorization theorem for a process described at subleading power in soft-collinear effective theory, we discuss the resummation of Sudakov logarithms for such processes in renormalization-group improved perturbation theory. Endpoint divergences in convolution integrals, which arise generically beyond leading power, are regularized and removed by systematically rearranging the factorization formula. We study in detail the example of the $b$-quark induced $h\to \gamma \gamma$ decay of the Higgs boson, for which we resum large logarithms of the ratio $M_h/m_b$ at next-to-leading logarithmic order. We also briefly discuss the related $gg\to h$ amplitude.

    hep-phhep-thPRD(2021)·88 citations
15. 15*

    Two-loop analysis of the pion-mass dependence of the $\rho$ meson

    Malwin Niehus🇩🇪 · Martin Hoferichter🇨🇭 · Bastian Kubis🇩🇪 · Jacobo Ruiz de Elvira🇨🇭

    Analyzing the pion-mass dependence of $\pi \pi$ scattering phase shifts beyond the low-energy region requires the unitarization of the amplitudes from chiral perturbation theory. In the two-flavor theory, unitarization via the inverse-amplitude method (IAM) can be justified from dispersion relations, which is therefore expected to provide reliable predictions for the pion-mass dependence of results from lattice QCD calculations. In this work, we provide compact analytic expression for the two-loop partial-wave amplitudes for $J=0,1,2$ required for the IAM at subleading order. To analyze the pion-mass dependence of recent lattice QCD results for the $P$-wave, we develop a fit strategy that for the first time allows us to perform stable two-loop IAM fits and assess the chiral convergence of the IAM approach. While the comparison of subsequent orders suggests a breakdown scale not much below the $\rho$ mass, a detailed understanding of the systematic uncertainties of lattice QCD data is critical to obtain acceptable fits, especially at larger pion masses.

    hep-phhep-latnucl-thPRL(2021)·52 citations
16. 16*

    String Perturbation Theory on the Schwinger-Keldysh Time Contour

    Petr Horava🇺🇸 · Christopher J. Mogni🇺🇸

    We perform the large-$N$ expansion in the Schwinger-Keldysh formulation of non-equilibrium quantum systems with matrix degrees of freedom, and study universal features of the anticipated dual string theory. We find a rich refinement of the topological genus expansion: In the original formulation, the future time instant where the forward and backward branches of the Schwinger-Keldysh time contour meet is associated with its own worldsheet genus expansion. After the Keldysh rotation, the worldsheets decompose into a classical and quantum part.

    ↳ hep-thastro-ph.COcond-mat.othergr-qc+1PRL(2020)·16 citations
17. 17*

    Neutral-current background induced by atmospheric neutrinos at large liquid-scintillator detectors: II. Methodology for in situ measurements

    Jie Cheng🇨🇳 · Yu-Feng Li🇨🇳 · Hao-Qi Lu🇨🇳 · Liang-Jian Wen🇨🇳

    Future large liquid-scintillator (LS) detectors are competitive with and complementary to the water-Cherenkov detectors on the searches for diffuse supernova neutrino background and nucleon decay. In a companion paper, we have performed a systematic calculation of the neutral-current (NC) background induced by atmospheric neutrino interactions on ${}^{12}\mathrm{C}$ nuclei in LS detectors, which are expected to be crucially important for the experimental searches for the diffuse supernova neutrino background and nucleon decay. In this paper, we perform a systematic study on the measurement of the NC background and evaluate the associated uncertainties. We first exploit the characteristics of the NC background, in particular, the multiplicities of neutrons and pions, and the possible association with unstable residual nuclei. It turns out that the neutron multiplicity distribution is very powerful to discriminate among different models. Then, we develop a maximum-likelihood method to allow an {\it in situ} measurement of the NC interactions with a triple-coincidence signature. Finally, a data-driven approach is proposed to evaluate the uncertainty of the NC background in the search for the diffuse supernova neutrino background. We conclude that future large LS experiments like JUNO (Jiangmen Underground Neutrino Observatory) will be able to make a unique contribution to the worldwide data set to improve the prediction of atmospheric neutrino NC interactions on ${}^{12}$C.

    ↳ hep-exastro-ph.HEhep-phnucl-ex+1PRD(2021)·18 citations
18. 18*

    Minimum variance estimation of statistical anisotropy via galaxy survey

    Maresuke Shiraishi🇯🇵 · Teppei Okumura🇹🇼 · Kazuyuki Akitsu🇯🇵

    We consider the benefits of measuring cosmic statistical anisotropy from redshift-space correlators of the galaxy number density fluctuation and the peculiar velocity field without adopting the plane-parallel (PP) approximation. Since the correlators are decomposed using the general tripolar spherical harmonic (TripoSH) basis, we can deal with wide-angle contributions untreatable by the PP approximation, and at the same time, target anisotropic signatures can be cleanly extracted. We, for the first time, compute the covariance of the TripoSH decomposition coefficient and the Fisher matrix to forecast the detectability of statistical anisotropy. The resultant expression of the covariance is free from nontrivial mixings between each multipole moment caused by the PP approximation and hence the detectability is fully optimized. Compared with the analysis under the PP approximation, the superiority in detectability is always confirmed, and it is highlighted, especially in the cases that the shot noise level is large and that target statistical anisotropy has a blue-tilted shape in Fourier space. The application of the TripoSH-based analysis to forthcoming all-sky survey data could result in constraints on anisotropy comparable to or tighter than the current cosmic microwave background ones.

    ↳ astro-ph.COgr-qchep-phJCAP(2021)·8 citations
19. 19*

    Palatini Higgs and Coleman-Weinberg inflation with non-minimal coupling

    Nilay Bostan🇺🇸

    We present the impact of non-minimal coupling $\xi {\varphi }^{2}R$ on the inflationary parameters by taking into account the models of single-field inflation with the inflaton that has a non-zero vacuum expectation value ($v$) after the period of inflation in Palatini gravity. We discuss the well-known symmetry breaking type potentials, namely the Higgs potential and Coleman-Weinberg potential. We show the inflationary predictions of these potentials, for both $\varphi >v$ and $\varphi <v$ inflation, the regions in the $v-\xi$ plane for which the values of $n_s$ and $r$ are in agreement with the recent measurements. We also show the linear inflation behavior as a solution of Coleman-Weinberg potential for $\xi v^2=1$ limit. Finally, we take into account the inflationary predictions of Coleman-Weinberg potential for preferred $\xi$ values as a function of $v$ in Palatini formalism.

    ↳ gr-qcastro-ph.COhep-phJCAP(2021)·10 citations
20. 20*

    Photon-jet correlations in p-p and Pb-Pb collisions using JETSCAPE framework

    C. Sirimanna · A. Angerami · S. A. Bass · S. Cao · Y. Chen · J. Coleman · L. Cunqueiro · T. Dai · L. Du · R. Ehlers · H. Elfner · D. Everett and 38 other authors

    It is now well established that jet modification is a multistage effect; hence a single model alone cannot describe all facets of jet modification. The JETSCAPE framework is a multistage framework that uses several modules to simulate different stages of jet propagation through the QGP medium. These simulations require a set of parameters to ensure a smooth transition between stages. We fine tune these parameters to successfully describe a variety of observables, such as the nuclear modification factors of leading hadrons and jets, jet shape, and jet fragmentation function. Photons can be produced in the hard scattering or as radiation from quarks inside jets. In this work, we study photon-jet transverse momentum imbalance and azimuthal correlation for both $p-p$ and $Pb-Pb$ collision systems. All the photons produced in each event, including the photons from hard scattering, radiation from the parton shower, and radiation from hadronization are considered with an isolation cut to directly compare with experimental data. The simulations are conducted using the same set of tuned parameters as used for the jet analysis. No new parameters are introduced or tuned. We demonstrate a significantly improved agreement with photons from $Pb-Pb$ collisions compared to prior efforts. This work provides an independent, parameter free verification of the multistage evolution framework.

    ↳ nucl-thhep-phPoS(2021)·1 citation

* 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.