Thu·Jan 6, 2022Thursday·January 6, 2022

1. 01*

   A Stable Sexaquark: Overview and Discovery Strategies

   Glennys R. Farrar🇺🇸

   The neutral, flavor singlet scalar uuddss bound state -- the sexaquark, S -- may have a low enough mass to be stable or extremely long-lived. Here we review mass estimates and production expectations and show that laboratory experiments to date do not rule out such a long-lived state. An S with mass below 2054 MeV is either absolutely stable or has a lifetime greater than the age of the Universe. Detection of a stable S in accelerator experiments is very challenging. An examination of the experimental literature shows that such an effectively stable state would have escaped detection. The strongest laboratory constraint on a long-lived S comes from the lower-bound on its formation time in a doubly-strange hypernucleus; this constraint is, however, not stringent enough to exclude a stable S. We develop strategies to discover it. A stable S would be an attractive dark matter candidate. Relevant astrophysical and cosmological observations, which show that sexaquark dark matter is consistent with all current knowledge, are briefly reviewed.

   hep-phastro-ph.CO25 citations
2. 02*

   Reconstruction of Air-Shower Parameters Through the Lateral Distribution Function of Ultra-High Energy Particles

   Kadhom F. Fadhel🇮🇶 · A. A. Al-Rubaiee🇮🇶

   In this study, the necessity of the simulation study for exploring the interactions of ultra-high energy particles cosmic rays was examined. Different hadronic interaction models such as (SIBYLL, QGSJET, and EPOS) were simulated by using air showers simulation AIRES system (version 19.04.00). Also, the charged particle density of Extensive Air Showers (EAS) was calculated by estimating the lateral distribution function (LDF). Moreover, the LDF simulation of the two primary particles (proton and iron nuclei) was performed, taking into account their primary energies effect and the zenith angle of charged particles that produced in the EAS, within the energy range (10^17-10^19) eV. At extremely high energies (10^17, 10^18, and 10^19) eV, new parameters as a function of the primary energy were obtained by fitting the lateral distribution curves of EAS using Sigmoidal function (Logistic model). Comparison of the results showed a good agreement between the values obtained from the parameterized LDF using Sigmoidal function with experimental results by AGASA EAS observatory for the primaries proton as well iron nuclei, with the production of (electron positron) pair and the charged muons secondary particles at high energy about 10^19 eV and (theta = 0 degree).

   hep-phastro-ph.HEActa Phys.Polon.A(2021)·0 citations
3. 03*

   Axions, Time Varying CP Violation, and Baryogenesis

   Lawrence M. Krauss (Origins Project Foundation)🇺🇸

   We derive two features of axion cosmology that may have cosmological implications, whether or not axions are dark matter: For the full range of allowed axion masses, the evolution of a cosmic axion background allows large CP violation until temperatures as low as $\sim$ 2 GeV, and once the axion field begins to oscillate, the cosmological axion field's relaxation to its ground state can briefly provide a new departure from thermal equilibrium, via time-varying CP violation. During both of these periods, the Strong CP violating parameter $\bar{\theta }$ can be as large as O(1).

   hep-phastro-ph.CO1 citation
4. 04*

   Hyperon production in quasielastic ${\bar{\nu }}_{\tau }-$nucleon scattering

   A. Fatima🇮🇳 · M. Sajjad Athar🇮🇳 · S. K. Singh🇮🇳

   The theoretical results for the total cross sections and polarization components of the ${\tau }^{+}$ lepton produced in the charged current induced $|\Delta S|=1$ quasielastic ${\bar{\nu }}_{\tau }-N$ scattering leading to hyperons ($\Lambda ,\Sigma$) have been presented assuming T invariance. The theoretical uncertainties arising due to the use of different vector, axial vector and pseudoscalar form factors as well as the effect of SU(3) symmetry breaking have been studied. We have also presented, for the first time, a comparison of the total cross sections for the production of $e,\mu ,\tau$ leptons to facilitate the implications of lepton flavor universality~(LFU) in the $|\Delta S|=1$ quasielastic reactions induced by the antineutrinos of all flavors i.e., ${\nu }_l;l=e,\mu ,\tau$.

   hep-phhep-exnucl-thPRD(2022)·5 citations
5. 05*

   Quantum integration of elementary particle processes

   Gabriele Agliardi🇮🇹 · Michele Grossi🇨🇭 · Mathieu Pellen🇩🇪 · Enrico Prati🇮🇹

   We apply quantum integration to elementary particle-physics processes. In particular, we look at scattering processes such as ${\mathrm{e}}^{+}{\mathrm{e}}^{-}\to q\bar{q}$ and ${\mathrm{e}}^{+}{\mathrm{e}}^{-}\to q{\bar{q}}^{\prime }\mathrm{W}$. The corresponding probability distributions can be first appropriately loaded on a quantum computer using either quantum Generative Adversarial Networks or an exact method. The distributions are then integrated sing the method of Quantum Amplitude Estimation which shows a quadratic speed-up with respect to classical techniques. In simulations of noiseless quantum computers, we obtain per-cent accurate results for one- and two-dimensional integration with up to six qubits. This work paves the way towards taking advantage of quantum algorithms for the integration of high-energy processes.

   hep-phquant-phPLB(2022)·45 citations
6. 06*

   Nuclei in the toy world: beyond the Pomeron in zero transverse dimensions

   A. Kovner (UCONN)🇺🇸 · E. Levin (Tel Aviv U./UTFSM)🇮🇱 · M. Lublinsky (Ben Gurion U.)🇮🇱

   We explore possible extensions of the $t$-channel and $s$-channel unitary model of high energy evolution in zero transverse dimensions appropriate to very high energy/atomic number where the dipole density in a toy hadron is parametrically high.We suggest that the appropriate generalization is to allow emission of more than one dipole in a single step of energy evolution. We construct explicitly such a model that preserves the $t$-channel and s-channel unitarity and have the correct low density limit, and study the particle multiplicity distribution resulting from this evolution. We consider initial conditions of a single dipole and many dipoles at initial rapidity. We observe that the saturation regime in this model is preceded by a parametric range of rapidities $\frac{1}{{\alpha }_s}\ln \frac{1}{{\alpha }_s}<Y<\frac{1}{{\alpha }_s}\ln \frac{1}{{\alpha }_s^2}$, where the saturation effects are still unimportant, but multiple emissions determine the properties of the evolution. We also discuss the influence of the saturation on the parton cascade and, in particular, find that in the saturation regime the entropy of partons becomes $S\approx \text{h}\ln N$ where $N$ is the mean multiplicity.

   hep-phJHEP(2022)·13 citations
7. 07*

   Uncertainties on the theoretical input for $t\bar{t}j$ experimental analyses at the LHC

   Katharina Voß🇩🇪 · Maria Vittoria Garzelli🇩🇪 · Sven-Olaf Moch🇩🇪

   The precise measurement of the top-quark mass constitutes one of the main goals of the LHC top-quark physics program. One possibility to extract this parameter uses the ${\rho }_{\mathrm{s}}$ distribution, which depends on the invariant mass of the $t\bar{t}j$ system. To fully take advantage of the experimental accuracy achievable in measuring top quark production cross sections at the LHC, the theory uncertainties need to be well under control. We present a study of the effect of varying the input parameters of the theoretical calculation on the predicted ${\rho }_{\mathrm{s}}$ distribution. Thereby we studied the influence of the $R$ parameter in the jet reconstruction procedure, as well as the effect of various renormalization and factorization scale definitions and different PDF sets. A behaviour similar to the one presented here for the ${\rho }_{\mathrm{s}}$-distribution was also found for other differential distributions.

   hep-ph0 citations
8. 08*

   Comparison of methods for the calculation of the real dilogarithm regarding instruction-level parallelism

   Alexander Voigt🇩🇪

   We compare different methods for the computation of the real dilogarithm regarding their ability for using instruction-level parallelism when executed on appropriate CPUs. As a result we present an instruction-level-aware method and compare it to existing implementations.

   hep-phcs.MScs.NAmath.NA3 citations
9. 09*

   All Heavy Tetraquarks: The Dynamical Diquark Model and Other Approaches

   Richard F. Lebed🇺🇸

   The 2020 announcement by LHCb of a narrow structure $X(6900)$ in the di-$J/\psi$ spectrum -- a potential $c\bar{c}c\bar{c}$ state -- has opened a new era in hadronic spectroscopy. In this talk, we briefly survey theory works preceding this event, examine key features of the observed spectrum, and then discuss how subsequent theory studies (including with the author's own dynamical diquark model) have interpreted these features. We conclude with proposals for experiments capable of distinguishing competing interpretations.

   hep-phMoscow Univ.Phys.Bull.(2022)·2 citations
10. 10*

    Pair production in strong electric fields

    Zhiyu Lei🇨🇳 · Bolun Hu🇨🇳 · Xingbo Zhao🇨🇳

    We study the electron-positron pair production process in strong background electric fields with spatio-temporal inhomogeneity in the time-dependent Basis Light-front Quantization approach. We calculate the observables such as the invariant mass and the longitudinal momentum distribution of the produced pairs as functions of evolution time and compare the vacuum decay rate with that of the Schwinger effect. We observe a critical intensity of background field, above which the vacuum decay rate is no longer oscillating with time periodically as in perturbation theory. This work may provide the foundation for the study of the pair production process in strong fields with realistic spacetime structures.

    hep-ph8 citations
11. 11*

    Two-loop mixed QCD-EW corrections to neutral current Drell-Yan

    Tommaso Armadillo🇮🇹 · Roberto Bonciani🇮🇹 · Simone Devoto🇮🇹 · Narayan Rana🇮🇹 · Alessandro Vicini🇮🇹

    We present the two-loop mixed strong-electroweak virtual corrections to the neutral current Drell-Yan process and we provide, in ancillary files, the explicit formulae of the infrared-subtracted finite remainder. The final state collinear singularities are regularised by the lepton mass. The evaluation of all the relevant Feynman integrals, including those with up to two internal massive lines, has been worked out relying on analytical and semi-analytical techniques, in the case of complex-valued masses.

    hep-phJHEP(2022)·59 citations
12. 12*

    Neural network reconstruction of the dense matter equation of state from neutron star observables

    Shriya Soma🇩🇪 · Lingxiao Wang🇩🇪 · Shuzhe Shi🇨🇦 · Horst Stöcker🇩🇪 · Kai Zhou🇩🇪

    The Equation of State (EoS) of strongly interacting cold and hot ultra-dense QCD matter remains a major challenge in the field of nuclear astrophysics. With the advancements in measurements of neutron star masses, radii, and tidal deformabilities, from electromagnetic and gravitational wave observations, neutron stars play an important role in constraining the ultra-dense QCD matter EoS. In this work, we present a novel method that exploits deep learning techniques to reconstruct the neutron star EoS from mass-radius (M-R) observations. We employ neural networks (NNs) to represent the EoS in a model-independent way, within the range of $\sim$1-7 times the nuclear saturation density. The unsupervised Automatic Differentiation (AD) framework is implemented to optimize the EoS, so as to yield through TOV equations, an M-R curve that best fits the observations. We demonstrate that this method works by rebuilding the EoS on mock data, i.e., mass-radius pairs derived from a randomly generated polytropic EoS. The reconstructed EoS fits the mock data with reasonable accuracy, using just 11 mock M-R pairs observations, close to the current number of actual observations.

    hep-phastro-ph.HEastro-ph.IMnucl-thJCAP(2022)·57 citations
13. 13*

    Motion induced excitation and radiation from an atom facing a mirror

    C.D. Fosco🇦🇷 · F.C. Lombardo🇦🇷 · F.D. Mazzitelli🇦🇷

    We study quantum dissipative effects due to the non-relativistic, bounded, accelerated motion of a single neutral atom in the presence of a planar perfect mirror, i.e. a perfect conductor at all frequencies. We consider a simplified model whereby a moving `scalar atom' is coupled to a quantum real scalar field, subjected to either Dirichlet or Neumann boundary conditions on the plane. We use an expansion in powers of the departure of the atom with respect to a static average position, to compute the vacuum persistence amplitude, and the resulting vacuum decay probability. We evaluate transition amplitudes corresponding to the excitation of the atom plus the emission of a particle, and show explicitly that the vacuum decay probabilities match the results obtained by integrating the transition amplitudes over the directions of the emitted particle. We also compute the spontaneous emission rate of an oscillating atom that is initially in an excited state.

    ↳ quant-phcond-mat.otherhep-phhep-thPRD(2022)·2 citations
14. 14*

    The $\Lambda (1405)$ resonance as a genuine three-quark or molecular state

    B. Golli🇸🇮 · H. Osmanović🇧🇦 · S. Širca🇸🇮

    The mechanism for the formation of the $\Lambda (1405)$ resonance is studied in a chiral quark model that includes quark-meson as well as contact (four point) interactions. The negative-parity $S$-wave scattering amplitudes for strangeness $-1$ and $1$ are calculated within a unified coupled-channel framework that includes the $KN$, $\bar{K}N$, $\pi \Sigma$, $\eta \Lambda$, $K\Xi$, $\pi \Lambda$, and $\eta \Sigma$ channels and possible genuine three-quark bare singlet and octet states corresponding to ${\frac{1}{2}}^{-}$ resonances. We show that in order to reproduce the scattering amplitudes in the $S_{01}$ partial wave it is important to include the pertinent three-quark octet states as well as the singlet state, while the inclusion of the contact term is not mandatory. The Laurent-Pietarinen expansion is used to determine the $S$-matrix poles. Following their evolution as a function of increasing interaction strength, the mass of the singlet state is strongly reduced due to the attractive self-energy in the $\pi \Sigma$ and $\bar{K}N$ channels; when it drops below the $KN$ threshold, the state acquires a dominant $\bar{K}N$ component which can be identified with a molecular state. The attraction between the kaon and the nucleon is generated through the $\bar{K}N{\Lambda }^{\ast }$ interaction rather than by meson-nucleon forces.

    ↳ nucl-thhep-phEPJA(2022)·0 citations
15. 15*

    A Chiral Mean-Field Equation-of-State in UrQMD: Effects on the Heavy Ion Compression Stage

    Manjunath Omana Kuttan🇩🇪 · Anton Motornenko🇩🇪 · Jan Steinheimer🇩🇪 · Horst Stoecker🇩🇪 · Yasushi Nara🇯🇵 · Marcus Bleicher🇩🇪

    It is shown that the initial compression in central heavy ion collisions at beam energies of $E_{\mathrm{lab}}=1-10A$~GeV depends dominantly on the underlying equation of state and only marginally on the model used for the dynamical description. To do so, a procedure to incorporate any equation of state in the UrQMD transport model is introduced. In particular we compare the baryon density, temperature and pressure evolution as well as produced entropy in a relativistic ideal hydrodynamics approach and the UrQMD transport model, where the same equation of state is used in both approaches. Not only is the compression similar if the same equation of state is used in either dynamical model, but it also strongly depends on the actual equation of state. These results indicate that the equation of state can be studied with observables which are sensitive to the initial compression phase and maximum compression achieved in heavy ion collisions at these beam energies.

    ↳ nucl-thhep-phEPJC(2022)·32 citations
16. 16*

    Constraints on sub-GeV dark matter boosted by cosmic rays from the CDEX-10 experiment at the China Jinping Underground Laboratory

    R. Xu🇨🇳 · L. T. Yang🇨🇳 · Q. Yue🇨🇳 · K. J. Kang🇨🇳 · Y. J. Li🇨🇳 · M. Agartioglu🇹🇼 · H. P. An🇨🇳 · J. P. Chang🇨🇳 · Y. H. Chen🇨🇳 · J. P. Cheng🇨🇳 · W. H. Dai🇨🇳 · Z. Deng🇨🇳 and 73 other authors

    We present new constraints on light dark matter boosted by cosmic rays (CRDM) using the 205.4 kg day data of the CDEX-10 experiment conducted at the China Jinping Underground Laboratory. The Monte Carlo simulation package CJPL\_ESS was employed to evaluate the Earth shielding effect. Several key factors have been introduced and discussed in our CRDM analysis, including the contributions from heavier CR nuclei than proton and helium, the inhomogeneity of CR distribution, and the impact of the form factor in the Earth attenuation calculation. Our result excludes the dark matter--nucleon elastic scattering cross-section region from $1.7\times 10^{-30}$ to $10^{-26}\mathrm{c}{\mathrm{m}}^2$ for dark matter of 10 keV$/c^2$ to 1 GeV$/c^2$.

    ↳ hep-exhep-phphysics.ins-detPRD(2022)·72 citations
17. 17*

    MiniBooNE and MicroBooNE Combined Fit to a 3+1 Sterile Neutrino Scenario

    A. A. Aguilar-Arevalo🇲🇽 · B. C. Brown🇺🇸 · J. M. Conrad🇺🇸 · R. Dharmapalan🇺🇸 · A. Diaz🇺🇸 · Z. Djurcic🇺🇸 · D. A. Finley🇺🇸 · R. Ford🇺🇸 · G. T. Garvey🇺🇸 · S. Gollapinni🇺🇸 · A. Hourlier🇺🇸 · E.-C. Huang🇺🇸 and 27 other authors

    This letter presents the results from the MiniBooNE experiment within a full "3+1" scenario where one sterile neutrino is introduced to the three-active-neutrino picture. In addition to electron-neutrino appearance at short-baselines, this scenario also allows for disappearance of the muon-neutrino and electron-neutrino fluxes in the Booster Neutrino Beam, which is shared by the MicroBooNE experiment. We present the 3+1 fit to the MiniBooNE electron-(anti)neutrino and muon-(anti)neutrino data alone, and in combination with MicroBooNE electron-neutrino data. The best-fit parameters of the combined fit with the exclusive CCQE analysis (inclusive analysis) are $\Delta m^2=0.29e{V}^2(0.33e{V}^2)$, $|U_{e4}{|}^2=0.016(0.500)$, $|U_{\mu 4}{|}^2=0.500(0.500)$, and ${\sin }^2(2{\theta }_{\mu e})=0.0316(1.0)$. Comparing the no-oscillation scenario to the 3+1 model, the data prefer the 3+1 model with a $\Delta {\chi }^2/\text{dof}=24.7/3(17.3/3)$, a $4.3\sigma (3.4\sigma )$ preference assuming the asymptotic approximation given by Wilks' theorem.

    ↳ hep-exhep-phnucl-exPRL(2022)·52 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.