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Nuclear Theory·nucl-th

Monday·June 18, 2018

7 papers—3 primary·4 cross-listed

All7Primary3Cross-lists4
  1. 04

    Kubo formulas for thermodynamic transport coefficients

    Pavel Kovtun🇨🇦 · Ashish Shukla🇨🇦

    Uncharged relativistic fluids in 3+1 dimensions have three independent thermodynamic transport coefficients at second order in the derivative expansion. Fluids with a single global current have nine, out of which seven are parity preserving. We derive the Kubo formulas for all nine thermodynamic transport coefficients in terms of equilibrium correlation functions of the energy-momentum tensor and the current. All parity-preserving coefficients can be expressed in terms of two-point functions in flat space without external sources, while the parity-violating coefficients require three-point functions. We use the Kubo formulas to compute the thermodynamic coefficients in several examples of free field theories.

    ↳ hep-thhep-phnucl-thJHEP(2018)·43 citations
  2. 05

    Centrality dependence of kinetic freeze-out temperature and transverse flow velocity in high energy nuclear collisions

    Muhammad Waqas🇨🇳 · Fu-Hu Liu🇨🇳

    Centrality-dependent double-differential transverse momentum spectra of charged pions, kaons, and (anti)protons produced in mid-pseudorapidity interval in GeV gold-gold and deuteron-gold collisions with different centralities are analyzed by the blast-wave model with Boltzmann-Gibbs statistics. Meanwhile, the mentioned spectra in mid-rapidity interval in TeV lead-lead and TeV proton-lead collisions with different centralities are analyzed by the same model. The model results are approximately in agreement with the experimental data in special transverse momentum ranges. It is shown that with the increase of event centrality and energy, the kinetic freeze-out temperature of the emission source and the transverse flow velocity of the produced particles slightly increase in some cases but they do not give an obvious change in other cases. Meanwhile, the kinetic freeze-out temperature (transverse flow velocity) increases (decreases) with the increase of particle mass. The average transverse momentum and initial temperature increase with the increase of event centrality, collision energy, and particle mass. This work also confirms the maximum size dependent effect, which states that the main parameters such as the kinetic freeze-out temperature and transverse flow velocity are mainly determined by the heaviest nucleus from proton-nucleus to nucleus-nucleus collisions.

    ↳ hep-phhep-exnucl-exnucl-thIndian J.Phys.(2022)·26 citations
  3. 06

    Isoscalar Giant Monopole, Dipole, and Quadrupole Resonances in Zr and Mo

    Y. K. Gupta · K. B. Howard · U. Garg · J. T. Matta · M. Senyigit · M. Itoh · S. Ando · T. Aoki · A. Uchiyama · S. Adachi · M. Fujiwara · C. Iwamoto and 10 other authors

    The isoscalar giant monopole, dipole, and quadrupole strength distributions have been deduced in Zr, and Mo from "background-free" spectra of inelastic -particle scattering at a beam energy of 385 MeV at extremely forward angles, including 0. These strength distributions were extracted by a multipole-decomposition analysis based on the expected angular distributions of the respective multipoles. All these strength distributions for the three nuclei practically coincide with each other, affirming that giant resonances, being collective phenomena, are not influenced by nuclear shell structure near 90, contrary to the claim in a recent measurement.

    ↳ nucl-exnucl-thPRC(2018)·30 citations
  4. 07

    Short-Range Neutrinoless Double Beta Decay Mechanisms

    Lukas Graf🇬🇧 · Frank F. Deppisch🇬🇧 · Francesco Iachello🇺🇸 · Jenni Kotila🇫🇮

    Neutrinoless double beta decay can significantly help to shed light on the issue of non-zero neutrino mass, as observation of this lepton number violating process would imply neutrinos are Majorana particles. However, the underlying interaction does not have to be as simple as the standard neutrino mass mechanism. The entire variety of neutrinoless double beta decay mechanisms can be approached effectively. In this work we focus on a theoretical description of short-range effective contributions to neutrinoless double beta decay, which are equivalent to 9-dimensional effective operators incorporating the appropriate field content. We give a detailed derivation of the nuclear matrix elements and phase space factors corresponding to individual terms of the effective Lagrangian. Using these, we provide general formulae for the neutrinoless double beta decay half-life and angular correlation of the outgoing electrons.

    ↳ hep-phnucl-thPRD(2018)·73 citations

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first authorsco-authorsvia INSPIRE