PaperPanorama
FAQ

Nuclear Theory·nucl-th

Wednesday·July 26, 2017

10 papers—5 primary·5 cross-listed

All10Primary5Cross-lists5
  1. 01

    Analysis of the Daya Bay Reactor Antineutrino Flux Changes with Fuel Burnup

    Anna Hayes🇺🇸 · Gerard Jungman🇺🇸 · Libby McCutchan🇺🇸 · Alejandro Sonzogni🇺🇸 · Gerry Garvey🇺🇸 · Xiaobao Wang🇨🇳

    We investigate the recent Daya Bay results on the changes in the antineutrino flux and spectrum with the burnup of the reactor fuel. We find that the discrepancy between current model predictions and the Daya Bay results can be traced to the original measured U/Pu ratio of the fission beta spectra that were used as a base for the expected antineutrino fluxes. An analysis of the antineutrino spectra that is based on a summation over all fission fragment beta-decays, using nuclear database input, explains all of the features seen in the Daya Bay evolution data. However, this summation method still predicts an anomaly. Thus, we conclude that there is currently not enough information to use the antineutrino flux changes to rule out the possible existence of sterile neutrinos.

    nucl-thhep-exhep-phnucl-exPRL(2018)·53 citations
  2. 02

    Fixed-t analyticity as a constraint in single energy partial wave analyses of meson photoproduction reactions

    H. Osmanović🇧🇦 · M. Hadžimehmedović🇧🇦 · R. Omerović🇧🇦 · J. Stahov🇧🇦 · V. Kashevarov🇩🇪 · K. Nikonov🇩🇪 · M. Ostrick🇩🇪 · L. Tiator🇩🇪 · A. Švarc🇭🇷

    Partial wave amplitudes of meson photoproduction reactions are an important source of information in baryon spectroscopy. We investigate a new approach in single-energy partial wave analyses of these reactions. Instead of using a constraint to theoretical models in order to achieve solutions which are continuous in energy, we enforce the analyticity of the amplitudes at fixed values of the Mandelstam variable . We present an iterative procedure with successive fixed- amplitude analyses which constrain the single-energy partial wave analyses and apply this method to the reaction. We use pseudo data, generated by the EtaMAID model, to test the method and to analyze ambiguities. Finally, we present an analytically constrained partial wave analysis using experimental data for four polarization observables recently measured at MAMI and GRAAL in the energy range from threshold to GeV.

    nucl-thPRC(2018)·15 citations
  3. 03

    Evolution of pressures and correlations in the Glasma produced in high energy nuclear collisions

    M. Ruggieri🇨🇳 · J. H. Liu🇮🇹 · L. Oliva. G. X. Peng🇨🇳 · V. Greco🇮🇹

    We consider the SU(2) Glasma with gaussian fluctuations and study its evolution by means of classical Yang-Mills equations solved numerically on a lattice. Neglecting in this first study the longitudinal expansion we follow the evolution of the pressures of the system and compute the effect of the fluctuations in the early stage up to fm/c, that is the time range in which the Glasma is relevant for high energy collisions. We measure the ratio of the longitudinal over the transverse pressure, , and we find that unless the fluctuations carry a substantial amount of the energy density at the initial time, they do not change significantly the evolution of in the early stage, and that the system remains quite anisotropic. We also measure the longitudinal fields correlators both in the transverse plane and along the longitudinal direction: while at initial time fields appear to be anticorrelated in the transverse plane, this anticorrelation disappears in the very early stage and the correlation length in the transverse plane increases; on the other hand, we find that the longitudinal correlator decreases for a small longitudinal separation while being approximately constant for larger separation, which we interpret as a partial loss of longitudinal correlation induced by the dynamics.

    nucl-thhep-thPRD(2018)·19 citations
  4. 04

    Collective longitudinal polarization in relativistic heavy-ion collisions at very high energy

    F. Becattini (1)🇮🇹 · Iu. Karpenko (2) ((1) U. Florence (2) INFN Florence)🇮🇹

    We study the polarization of particles in relativistic heavy-ion collisions at very high energy along the beam direction within a relativistic hydrodynamic framework. We show that this component of the polarization decreases much slower with center-of-mass energy compared to the transverse component, even in the ideal longitudinal boost-invariant scenario with non-fluctuating initial state, and that it can be measured by taking advantage of its quadrupole structure in the transverse momentum plane. In the ideal longitudinal boost-invariant scenario, the polarization is proportional to the gradient of temperature at the hadronization and its measurement can provide important information about the cooling rate of the Quark Gluon Plasma around the critical temperature.

    nucl-thhep-phPRL(2018)·242 citations
  5. 05

    Extended Chiral Quark Models in the Framework of Quantum Chromodynamic: Theory and their Applications in Hot and Dense Mediums

    M. Abu-Shady🇪🇬

    In this review article, we give overview on the extended chiral quark models. In particular, how these models are extended to include the higher-order interactions, quantized fields, logarithmic potential and the effect of these modifications on hadron properties at hot and dense mediums. In addition, how we deal with non-normalization of the Nambu-Jona-Lasinio (NJL) model by using mid-point technique. Therefore, the extended quark models give satisfied results in comparison with lattice QCD at finite temperature and baryonic chemical potential. The extra effort is needed to deal with chiral quark models in the presence of external magnetic field at finite temperature and density.

    nucl-thOpen Access Journal of Physics, Volume 1,…·1 citation

Affiliations

first authorsco-authorsvia INSPIRE