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Nuclear Theory·nucl-th

Monday·June 10, 2019

5 papers—2 primary·3 cross-listed

All5Primary2Cross-lists3
  1. 01

    Properties of isospin asymmetric matter derived from chiral effective field theory

    Randy Millerson · Francesca Sammarruca

    We present and discuss properties of isospin asymmetric matter whose equation of state is derived from recent high-quality chiral nucleon-nucleon potentials and chiral effective three-nucleon forces. After a brief review of the chiral few-nucleon forces which we adopt, we concentrate on the symmetry energy and its density derivatives. We also explore the correlation between the symmetry energy at saturation density and its slope parameter, L. We estimate the truncation error across three orders of the chiral expansion for both the symmetry energy as a function of density and the slope parameter. Through an energy-density functional inspired by the liquid drop model, we establish a simple connection to finite nuclei. Specifically, we address the symmetry energy coefficient, the so-called reference (or equivalent) density, as well as the neutron skin thickness for 208Pb and 48Ca.

    nucl-th5 citations
  2. 02

    -Dependent Particle Number Fluctuations From Principal Component Analyses in Hydrodynamic Simulations of Heavy-Ion Collisions

    Fernando G. Gardim🇧🇷 · Frédérique Grassi🇧🇷 · Pedro Ishida🇧🇷 · Matthew Luzum🇧🇷 · Jean-Yves Ollitrault🇫🇷

    We carry out a principal component analysis of fluctuations in a hydrodynamic simulation of heavy-ion collisions, and compare with experimental data from the CMS collaboration. The leading and subleading principal components of elliptic and triangular flow reproduce the trends seen in data. By contrast, the principal components of multiplicity fluctuations show an interesting difference in their dependence for simulations compared to experimental data. Specifically, the leading component increases with in hydrodynamics, while it is constant in experiment. In order to understand how the leading and subleading modes arise, we construct a toy model where the principal components have a simple analytic form. We show how the PCA components depend on fluctuations of the average transverse momentum and of the total multiplicity, as well as correlations between the two, and we verify that hydrodynamic simulations agree with the predictions of the toy model. The difference in the momentum trend is likely due to the fact that hydrodynamic models typically have transverse momentum fluctuations that are larger than seen experimentally.

    nucl-thhep-phnucl-exPRC(2019)·30 citations
  3. 03

    Progress and Simulations for Intranuclear Neutron--Antineutron Transformations in

    Joshua L. Barrow🇺🇸 · Elena S. Golubeva🇷🇺 · Eduard Paryev🇷🇺 · Jean-Marc Richard🇫🇷

    With the imminent construction of the Deep Underground Neutrino Experiment (DUNE) and Hyper-Kamiokande, nucleon decay searches as a means to constrain beyond Standard Model (BSM) extensions are once again at the forefront of fundamental physics. Abundant neutrons within these large experimental volumes, along with future high-intensity neutron beams such as the European Spallation Source, offer a powerful, high-precision portal onto this physics through searches for and violating processes such as neutron--antineutron transformations (), a key prediction of compelling theories of baryogenesis. With this in mind, this paper discusses a novel and self-consistent intranuclear simulation of this process within , which plays the role of both detector and target within DUNE's gigantic liquid argon time projection chambers. An accurate and independent simulation of the resulting intranuclear annihilation respecting important physical correlations and cascade dynamics for this large nucleus is necessary to understand the viability of such rare searches when contrasted against background sources such as atmospheric neutrinos. Recent theoretical improvements to our model, including the first calculation of 's -intranuclear suppression factor, and Monte Carlo simulation comparisons to another publicly available generator within GENIE, are also discussed.

    ↳ hep-exhep-phnucl-thPRD(2020)·45 citations
  4. 04

    Canonical statistical model analysis of p-p, p-Pb, and Pb-Pb collisions at the LHC

    Volodymyr Vovchenko🇩🇪 · Benjamin Dönigus🇩🇪 · Horst Stoecker🇩🇪

    The system-size dependence of hadrochemistry at vanishing baryon density is considered within the canonical statistical model (CSM) with local exact conservation of three conserved charges, allowing for a possibility of strangeness undersaturation, i.e. . Exact baryon number conservation is found to be even more important than that of strangeness in the canonical suppression picture at the LHC, in contrast to intermediate and low collision energies. The model is applied to p-p, p-Pb, and Pb-Pb data of the ALICE collaboration. A chemical equilibrium CSM with a fixed MeV describes the trends seen in most yield ratios. However, this vanilla version of CSM predicts an enhancement of the ratio at smaller multiplicities, in stark contrast to the suppression seen in the data. The data are described with a 15% relative accuracy level whence a multiplicity dependence of both the temperature and the strangeness saturation parameter is accepted. Both the canonical suppression and the strangeness undersaturation effects are small at , but they do improve substantially the description of hadron yields in p-p collisions, in particular the yields. A possibility to constrain the rapidity correlation volume using net-proton fluctuation measurements is pointed out.

    ↳ hep-phnucl-exnucl-thPRC(2019)·140 citations
  5. 05

    Influence of quark masses and strangeness degrees of freedom on inhomogeneous chiral phases

    Michael Buballa🇩🇪 · Stefano Carignano🇪🇸

    Several model calculations of the QCD phase structure at nonzero temperature and density suggest that in certain regions of the phase diagram inhomogeneous condensates are favored over homogeneous ones. In particular, in a two-flavor NJL model in the chiral limit the would-be first-order boundary associated with the chiral phase transition is entirely covered by an inhomogeneous phase, characterized by a spatially modulated chiral condensate, whose tip coincides exactly with the chiral critical point. In this contribution we discuss how this result is altered by the inclusion of nonzero quark masses and strange quarks in the model.

    ↳ hep-phnucl-thPoS(2019)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE