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Nuclear Theory·nucl-th

Friday·August 21, 2020

9 papers—5 primary·4 cross-listed

All9Primary5Cross-lists4
  1. 01

    From Chiral Kinetic Theory To Relativistic Viscous Spin Hydrodynamics

    Shuzhe Shi🇨🇦 · Charles Gale🇨🇦 · Sangyong Jeon🇨🇦

    In this work, we start with chiral kinetic theory and construct the spin hydrodynamic framework for a chiral spinor system. Using the 14-moment expansion formalism, we obtain the equations of motion of second-order dissipative relativistic fluid dynamics with non-trivial spin polarization density. In a chiral spinor system, the spin alignment effect could be treated in the same framework as the Chiral Vortical Effect (CVE). However, the quantum corrections due to fluid vorticity induce not only CVE terms in the vector/axial charge currents but also corrections to the stress tensor. In this framework, viscous corrections to the hadron spin polarization are self-consistently obtained, which will be important for the precise prediction of the polarization rate for the observed hadrons, e.g. -hyperon.

    nucl-thhep-phPRC(2021)·144 citations
  2. 02

    Charge Conservation and Higher Moments of Charge Fluctuations

    Scott Pratt🇺🇸 · Rachel Steinhorst🇺🇸

    Higher moments of distributions of net charge and baryon number in heavy-ion collisions have been proposed as signals of fundamental QCD phase transitions. In order to better understand background processes for these observables, models are presented which enable one to gauge the effects of local charge conservation, decays of resonances and clusters, Bose symmetrization, and volume fluctuations. Monte Carlo methods for generating samplings of particles consistent with local charge conservation are presented, and are followed by a review of simple analytic models involving a single type of charge with a constant experimental efficiency. The main model consists of thermal emission superimposed onto a simple parameterization of collective flow, known as a blast-wave, with emission being consistent with individual canonical ensembles. The spatial extent of local charge conservation is parameterized by the size and extent over which charge is conserved. The sensitivity of third and fourth order moments, skewness and kurtosis, to these parameters, and to beam energy and baryon density is explored. Comparisons with STAR data show that a significant part of the observed non-Poissonian fluctuations in net-proton fluctuations are explained by charge and baryon-number conservation, but that measurements of the STAR collaboration for fluctuations of net electric charge significantly differ from expectations of the models presented here.

    nucl-thPRC(2020)·11 citations
  3. 03

    Gluonic Hot Spot Initial Conditions in Heavy-Ion Collisions

    R. Snyder🇺🇸 · M. Byres🇺🇸 · S.H. Lim🇰🇷 · J.L. Nagle🇺🇸

    The initial conditions in heavy-ion collisions are calculated in many different frameworks. The importance of nucleon position fluctuations within the nucleus and sub-nucleon structure has been established when modeling initial conditions for input to hydrodynamic calculations. However, there remain outstanding puzzles regarding these initial conditions, including the measurement of the near equivalence of the elliptical and triangular flow coefficients in ultra-central 0-1% Pb+Pb collisions at the LHC. Recently a calculation termed MAGMA incorporating gluonic hot spots via two-point correlators in the Color Glass Condensate framework, and no nucleons, provided a simultaneous match to these flow coefficients measured by the ATLAS experiment, including in ultra-central 0-1% collisions. Our calculations reveal that the MAGMA initial conditions do not describe the experimental data when run through full hydrodynamic SONIC simulations or when the hot spots from one nucleus resolve hot spots from the other nucleus, as predicted in the Color Glass Condensate framework. We also explore alternative initial condition calculations and discuss their implications.

    nucl-thPRC(2021)·18 citations
  4. 04

    Octupole correlations in light actinides from the interacting boson model based on the Gogny energy density functional

    K. Nomura · R. Rodríguez-Guzmán · Y. M. Humadi · L. M. Robledo · J. E. García-Ramos

    The quadrupole-octupole coupling and the related spectroscopic properties have been studied for the even-even light actinides Ra and Th. The Hartree-Fock-Bogoliubov approximation, based on the Gogny-D1M energy density functional, has been employed as a microscopic input, i.e., to obtain (axially symmetric) mean-field potential energy surfaces as functions of the quadrupole and octupole deformation parameters. The mean-field potential energy surfaces have been mapped onto the corresponding bosonic potential energy surfaces using the expectation value of the Interacting Boson Model (IBM) Hamiltonian in the boson condensate state. The strength parameters of the -IBM Hamiltonian have been determined via this mapping procedure. The diagonalization of the mapped IBM Hamiltonian provides energies for positive- and negative-parity states as well as wave functions which are employed to obtain transitional strengths. The results of the calculations compare well with available data from Coulomb excitation experiments and point towards a pronounced octupole collectivity around Ra and Th.

    nucl-thnucl-exPRC(2020)·32 citations
  5. 05

    Early evolution constrained by high- QGP tomography

    Stefan Stojku🇷🇸 · Jussi Auvinen🇷🇸 · Marko Djordjevic🇷🇸 · Pasi Huovinen🇷🇸 · Magdalena Djordjevic🇷🇸

    We show that high- and are sensitive to the early expansion dynamics, and that the high- observables prefer delayed onset of energy loss and transverse expansion. To calculate high- and , we employ our newly developed DREENA-A framework, which combines state-of-the-art dynamical energy loss model with 3+1-dimensional hydrodynamical simulations. The model applies to both light and heavy flavor, and we predict a larger sensitivity of heavy flavor observables to the onset of transverse expansion. This presents the first time when bulk QGP behavior has been constrained by high- observables and related theory, i.e., by so-called QGP tomography.

    nucl-thhep-phPRC(2022)·23 citations

Affiliations

first authorsco-authorsvia INSPIRE