Nuclear Theory·nucl-th

Friday·February 10, 2017

6 papers—4 primary·2 cross-listed

01
Compton scattering off proton in the third resonance region
Xu Cao🇩🇪 · H. Lenske🇩🇪
Compton scattering off the proton in the third resonance region is analyzed for the first time, owing to the full combined analysis of pion- and photo-induced reactions in a coupled-channel effective Lagrangian model with K-matrix approximation. Two isospin $I = 3/2$ resonances $D_{33} (1700)$ and $F_{35} (1930)$ are found to be essential in the range of 1.6 - 1.8 GeV. The recent beam asymmetry data of Compton scattering from the GRAAL facility are used to determine the helicity couplings of these resonances, and strong constraints are coming also from $π N$ and $K Σ$ photoproduction data. The possible spin and parity of new narrow resonances is discussed.
nucl-thhep-phPLB(2017)·5 citations
02
Gamow-Teller transitions and proton-neutron pair correlation in $N = Z =$ odd $p$ -shell nuclei
Hiroyuki Morita · Yoshiko Kanada-En'yo
We have studied the Gamow-Teller (GT) transitions from $N = Z + 2$ neighbors to $N = Z =$ odd nuclei in $p$ -shell region by using isospin-projected and $β γ$ -constraint antisymmetrized molecular dynamics combined with generator coordinate method. The calculated GT transition strengths from $0^{+} 1$ states to $1^{+} 0$ states such as $^{6} He (0_{1}^{+} 1) \to^{6} Li (1_{1}^{+} 0)$ , $^{10} Be (0_{1}^{+} 1) \to^{10} B (1_{1}^{+} 0)$ , and $^{14} C (0_{1}^{+} 1) \to^{14} N (1_{2}^{+} 0)$ exhaust more than 50\% of the sum rule. These $N = Z + 2$ initial states and $N = Z =$ odd final states are found to dominantly have $S = 0, T = 1$ $nn$ pairs and $S = 1, T = 0$ $p n$ pairs, respectively. Based on two-nucleon ( $N N$ ) pair picture, we can understand the concentration of the GT strengths as the spin-isospin-flip transition $nn (S = 0, T = 1) \to p n (S = 1, T = 0)$ in $L S$ -coupling scheme. The GT transition can be a good probe to identify the spin-isospin partner states with $nn$ pairs and $p n$ pairs of $N = Z + 2$ and $N = Z =$ odd nuclei, respectively.
nucl-thPRC(2017)·7 citations
03
Neutron star crusts from mean field models constrained by chiral effective field theory
Yeunhwan Lim🇺🇸 · Jeremy W. Holt🇺🇸
We investigate the structure of neutron star crusts, including the crust-core boundary, based on new Skyrme mean field models constrained by the bulk-matter equation of state from chiral effective field theory and the ground-state energies of doubly-magic nuclei. Nuclear pasta phases are studied using both the liquid drop model as well as the Thomas-Fermi approximation. We compare the energy per nucleon for each geometry (spherical nuclei, cylindrical nuclei, nuclear slabs, cylindrical holes, and spherical holes) to obtain the ground state phase as a function of density. We find that the size of the Wigner-Seitz cell depends strongly on the model parameters, especially the coefficients of the density gradient interaction terms. We employ also the thermodynamic instability method to check the validity of the numerical solutions based on energy comparisons.
nucl-thPRC(2017)·73 citations
04
Investigating the temperature dependence of the specific shear viscosity of QCD matter with dilepton radiation
Gojko Vujanovic🇺🇸 · Gabriel S. Denicol🇧🇷 · Matthew Luzum🇧🇷 · Sangyong Jeon🇨🇦 · Charles Gale🇨🇦
This work reports on investigations of the effects on the evolution of viscous hydrodynamics and on the flow coefficients of thermal dileptons, originating from a temperature-dependent specific shear viscosity $η / s (T)$ at temperatures beyond 180 MeV formed at the Relativistic Heavy-Ion Collider (RHIC). We show that the elliptic flow of thermal dileptons can resolve the magnitude of $η / s$ at the high temperatures, where partonic degrees of freedom become relevant, whereas discriminating between different specific functional forms will likely not be possible at RHIC using this observable.
nucl-thhep-phnucl-exPRC(2018)·25 citations

Affiliations

first authorsco-authorsvia INSPIRE

Compton scattering off proton in the third resonance region

Gamow-Teller transitions and proton-neutron pair correlation in N=Z= odd p-shell nuclei

Neutron star crusts from mean field models constrained by chiral effective field theory

Investigating the temperature dependence of the specific shear viscosity of QCD matter with dilepton radiation

Affiliations

Gamow-Teller transitions and proton-neutron pair correlation in $N = Z =$ odd $p$ -shell nuclei