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Nuclear Theory·nucl-th

Tuesday·March 3, 2015

15 papers—6 primary·9 cross-listed

All15Primary6Cross-lists9
  1. 01

    Neutral current quasielastic (anti)neutrino scattering beyond the Fermi gas model at MiniBooNE and BNL kinematics

    M.V. Ivanov🇪🇸 · A.N. Antonov🇧🇬 · M.B. Barbaro🇮🇹 · C. Giusti🇮🇹 · A. Meucci🇮🇹 · J.A. Caballero🇪🇸 · R. Gonzalez-Jimenez🇪🇸 · E. Moya de Guerra🇪🇸 · J.M. Udias🇪🇸

    Neutral current quasielastic (anti)neutrino scattering cross sections on a C target are analyzed using a realistic spectral function that gives a scaling function in accordance with the () scattering data. The spectral function accounts for the nucleon-nucleon (NN) correlations by using natural orbitals (NOs) from the Jastrow correlation method and has a realistic energy dependence. The standard value of the axial mass GeV is used in all calculations. The role of the final-state interaction (FSI) on the spectral and scaling functions, as well as on the cross sections is accounted for. A comparison of the calculations with the empirical data of the MiniBooNE and BNL experiments is performed. Our results are analyzed in comparison with those when NN correlations are not included, and also with results from other theoretical approaches, such as the relativistic Fermi gas (RFG), the relativistic mean field (RMF), the relativistic Green's function (RGF), as well as with the SuperScaling Approach (SuSA) based on the analysis of quasielastic electron scattering.

    nucl-thPRC(2015)·17 citations
  2. 02

    Neutron-proton effective mass splitting in neutron-rich matter and its impacts on nuclear reactions

    Bao-An Li🇺🇸 · Lie-Wen Chen🇨🇳

    The neutron-proton effective mass splitting in neutron-rich nucleonic matter reflects the space-time nonlocality of the isovector nuclear interaction. It affects the neutron/proton ratio during the earlier evolution of the Universe, cooling of protoneutron stars, structure of rare isotopes and dynamics of heavy-ion collisions. While there is still no consensus on whether the neutron-proton effective mass splitting is negative, zero or positive and how it depends on the density as well as the isospin-asymmetry of the medium, significant progress has been made in recent yeas in addressing these issues. We first recall the connections among the neutron-proton effective mass splitting, the momentum dependence of the isovector potential and the density dependence of the symmetry energy. We then make a few observations about the progress in calculating the neutron-proton effective mass splitting using various nuclear many-body theories and its effects on the isospin-dependence of in-medium nucleon-nucleon cross sections. Perhaps, our most reliable knowledge so far about the neutron-proton effective mass splitting at saturation density of nuclear matter comes from optical model analyses of huge sets of nucleon-nucleus scattering data accumulated over the last five decades. The momentum dependence of the symmetry potential from these analyses provide a useful boundary condition at saturation density for calibrating nuclear many-body calculations. Several observables in heavy-ion collisions have been identified as sensitive probes of the neutron-proton effective mass splitting in dense neutron-rich matter based on transport model simulations. We review these observables and comment on the latest experimental findings.

    nucl-thastro-ph.SRnucl-exMod.Phys.Lett.A(2015)·32 citations
  3. 03

    Hydrodynamic modeling of 3He-Au collisions at sqrt(sNN)=200 GeV

    Piotr Bozek🇵🇱 · Wojciech Broniowski🇵🇱

    Collective flow and femtoscopy in ultrarelativistic 3He-Au collisions are investigated within the 3+1-dimensional (3+1D) viscous event-by-event hydrodynamics. We evaluate elliptic and triangular flow coefficients as functions of the transverse momentum. We find the typical long-range ridge structures in the two-particle correlations in the relative azimuth and pseudorapidity, in the pseudorapidity directions of both Au and 3He. We also make predictions for the pionic interferometric radii, which decrease with the transverse momentum of the pion pair. All features found hint on collectivity of the dynamics of the system formed in 3He-Au collisions, with hydrodynamics leading to quantitative agreement with the up-to-now released data.

    nucl-thnucl-exPLB(2015)·29 citations
  4. 04

    Constraining supernova equations of state with equilibrium constants from heavy-ion collisions

    Matthias Hempel🇨🇭 · Kris Hagel🇺🇸 · Joseph Natowitz🇺🇸 · Gerd Röpke🇩🇪 · Stefan Typel🇩🇪

    Cluster formation is a fundamental aspect of the equation of state (EOS) of warm and dense nuclear matter such as can be found in supernovae (SNe). Similar matter can be studied in heavy-ion collisions (HIC). We use the experimental data of Qin et al. [Phys. Rev. Lett. 108, 172701 (2012)] to test calculations of cluster formation and the role of in-medium modifications of cluster properties in SN EOSs. For the comparison between theory and experiment we use chemical equilibrium constants as the main observables. This reduces some of the systematic uncertainties and allows deviations from ideal gas behavior to be identified clearly. In the analysis, we carefully account for the differences between matter in SNe and HICs. We find that, at the lowest densities, the experiment and all theoretical models are consistent with the ideal gas behavior. At higher densities ideal behavior is clearly ruled out and interaction effects have to be considered. The contributions of continuum correlations are of relevance in the virial expansion and remain a difficult problem to solve at higher densities. We conclude that at the densities and temperatures discussed mean-field interactions of nucleons, inclusion of all relevant light clusters, and a suppression mechanism of clusters at high densities have to be incorporated in the SN EOS.

    nucl-thastro-ph.SRnucl-exPRC(2015)·56 citations
  5. 05

    The domain of validity of fluid dynamics and the onset of cavitation in ultrarelativistic heavy ion collisions

    Gabriel S. Denicol🇨🇦 · Charles Gale🇨🇦 · Sangyong Jeon🇨🇦

    If the bulk viscosity of QCD matter is large, the effective pressure of the hot and dense matter created in ultrarelativistic heavy ion collisions can become negative, leading to instabilities in the evolution of the plasma. In the context of heavy ion collisions, this effect is sometimes referred to as cavitation. In this contribution we discuss the onset of cavitation in event-by-event hydrodynamic simulations of ultrarelativistic heavy ion collisions at LHC energies. We estimate how large the bulk viscosity of the QGP has to be in the QCD (pseudo) phase transition region in order for the effective pressure of the system to actually become negative.

    nucl-thhep-phPoS(2015)·18 citations
  6. 06

    Toward relativistic mean-field description of -nucleus reactions

    T. Gaitanos🇬🇷 · M. Kaskulov🇩🇪

    In this work we study the antinucleon-nucleus optical potential in the framework of the non-linear derivative (NLD) model with momentum dependent mean-fields. We apply the NLD model to interaction of antinucleons () in nuclear matter and, in particular, to antiproton scattering on nuclei. In nuclear matter a strong suppression of the -optical potential at rest and at high kinetic energies is found and caused by the momentum dependence of relativistic mean-fields. The NLD results are consistent with known empirical -nucleus observations and agree well with antiproton-nucleus scattering data. This makes the NLD approach compatible with both, nucleon and antinucleon Dirac phenomenologies. Furthermore, in nuclear matter an effective mass splitting between nucleons and antinucleons is predicted.

    nucl-thNPA(2015)·29 citations

Affiliations

first authorsco-authorsvia INSPIRE