Nuclear Theory·nucl-th

Monday·October 5, 2015

12 papers—8 primary·4 cross-listed

01
[Submitted on 1 Oct 2015]
Dilepton emission in high-energy heavy-ion collisions with dissipative hydrodynamics
Gojko Vujanovic🇨🇦 · Gabriel S. Denicol🇺🇸 · Chun Shen🇨🇦 · Matthew Luzum🇪🇸 · Bjoern Schenke🇺🇸 · Sangyoung Jeon🇨🇦 · Charles Gale🇨🇦
In this contribution we study the effects of three transport coefficients of dissipative hydrodynamics on thermal dilepton anisotropic flow observables. The first two transport coefficients investigated influence the overall size and growth rate of shear viscous pressure, while the last transport coefficient governs the magnitude of net baryon number diffusion in relativistic dissipative fluid dynamics. All calculations are done using state-of-the-art 3+1D hydrodynamical simulations. We show that thermal dileptons are sensitive probes of the transport coefficients of dissipative hydrodynamics.
Comments:
Invited talk presented at CIPANP2015 (Twelfth Conference on the Intersections of Particle and Nuclear Physics, Vail, Colorado, USA, 19 - 24 May 2015); 10 pages, LaTeX, 8 PDF figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1510.00441 [pdf]
3 citations
02
[Submitted on 1 Oct 2015]
Properties of hot and dense matter from relativistic heavy ion collisions
Peter Braun-Munzinger🇩🇪 · Volker Koch🇺🇸 · Thomas Schaefer🇺🇸 · Johanna Stachel🇩🇪
We review the progress achieved in extracting the properties of hot and dense matter from relativistic heavy ion collisions at the relativistic heavy ion collider (RHIC) at Brookhaven National Laboratory and the large hadron collider (LHC) at CERN. We focus on bulk properties of the medium, in particular the evidence for thermalization, aspects of the equation of state, transport properties, as well as fluctuations and correlations. We also discuss the in-medium properties of hadrons with light and heavy quarks, and measurements of dileptons and quarkonia. This review is dedicated to the memory of Gerald E. Brown.
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1510.00442 [pdf]
Phys.Rept.(2016)·385 citations
03
[Submitted on 1 Oct 2015]
Microscopically constrained mean field models from chiral nuclear thermodynamics
Ermal Rrapaj🇺🇸 · Alessandro Roggero🇺🇸 · Jeremy W. Holt🇺🇸
We explore the use of mean field models to approximate microscopic nuclear equations of state derived from chiral effective field theory across the densities and temperatures relevant for simu- lating astrophysical phenomena such as core-collapse supernovae and binary neutron star mergers. We consider both relativistic mean field theory with scalar and vector meson exchange as well as energy density functionals based on Skyrme phenomenology and compare to thermodynamic equa- tions of state derived from chiral two- and three-nucleon forces in many-body perturbation theory. Quantum Monte Carlo simulations of symmetric nuclear matter and pure neutron matter are used to determine the density regimes in which perturbation theory with chiral nuclear forces is valid. Within the theoretical uncertainties associated with the many-body methods, we find that select mean field models describe well microscopic nuclear thermodynamics. As an additional consistency requirement, we study as well the single-particle properties of nucleons in a hot/dense environment, which affect e.g., charged-current weak reactions in neutron-rich matter. The identified mean field models can be used across a larger range of densities and temperatures in astrophysical simulations than more computationally expensive microscopic models.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1510.00444 [pdf]
PRC(2016)·42 citations
04
[Submitted on 2 Oct 2015]
Lightest Kaonic Nuclear Clusters
Roman Ya. Kezerashvili🇺🇸 · Shalva M. Tsiklauri🇺🇸 · Nurgali Zh. Takibayev🇰🇿
We present our study of kaonic three-body $K_N N$ , $K_K_N$ and $K K K_$ and four-body $K_$ , and $K_K_N N$ clusters within the framework of a potential model using the method of hyperspherical functions in momentum representation. To perform a numerical calculations for the bound state energy of the light kaonic system, we use a set of different potentials for the nucleon-nucleon and $K_N$ interactions, as well as for the kaon-kaon interaction. The calculations show that a quasibound state energy is not sensitive to the $N N$ interaction, and it shows very strong dependence on the $K_N$ potential. We also compare our results with those obtained using different theoretical approaches. The theoretical discrepancies in the binding energy and width for the lightest kaonic system related to the different $N N$ and $\overset{\_% }{K}N$ interactions are addressed.
Comments:
Talk presented CIPANP2015. 8 pages, LaTeX
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1510.00478 [pdf]
Phys.Sci.Tech.(2017)·6 citations
05
[Submitted on 2 Oct 2015]
Electron capture rates in stars studied with heavy ion charge exchange reactions
C.A. Bertulani
Indirect methods using nucleus-nucleus reactions at high energies (here, high energies mean $\sim$ 50 MeV/nucleon and higher) are now routinely used to extract information of interest for nuclear astrophysics. This is of extreme relevance as many of the nuclei involved in stellar evolution are short-lived. Therefore, indirect methods became the focus of recent studies carried out in major nuclear physics facilities. Among such methods, heavy ion charge exchange is thought to be a useful tool to infer Gamow-Teller matrix elements needed to describe electron capture rates in stars and also double beta-decay experiments. In this short review, I provide a theoretical guidance based on a simple reaction model for charge exchange reactions.
Comments:
6 pages, 2 figures, Invited contribution to the proceedings of "Nuclear Physics in Astrophysics" conference, York, England, May 18-22, 2015
Subjects:
Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Experiment (nucl-ex)
arXiv:
1510.00491 [pdf]
J.Phys.Conf.Ser.(2018)·1 citation
06
[Submitted on 2 Oct 2015]
Chemically non-equilibrated QGP and thermal photon elliptic flow
Akihiko Monnai🇺🇸
It has been discovered in recent heavy-ion experiments that elliptic and triangular flow of direct photons are underpredicted by most hydrodynamic models. I discuss possible enhancement mechanisms based on late chemical equilibration of the QGP and in-medium modification of parton distributions. Numerical hydrodynamic analyses indicate that they suppress early photon emission and visibly enhance thermal photon elliptic flow.
Comments:
4 pages, 5 figures - To appear in the conference proceedings for Hard Probes 2015, June 29-July 3, McGill University, Montreal, Canada
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1510.00539 [pdf]
Nucl.Part.Phys.Proc.(2016)·5 citations
07
[Submitted on 2 Oct 2015]
The Octet Meson and Octet Baryon Interaction with strangeness and the $Λ (1405)$
Jun He🇨🇳 · Pei-Liang Lu🇨🇳
The octet meson and baryon interaction with strangeness $S = - 1$ is studied fully relativistically with chiral Lagrangian. In this work, a Bethe-Salpeter equation approach with spectator quasipotential approximation is applied to study the reactions $K^{-} p \to M B$ with $M B = K^{-} p, K ˉ^{0} n, π^{-} Σ^{+}, π^{0} Σ^{0}, π^{+} Σ^{-}$ and $η Λ$ with all possible partial waves and theoretical results are comparable with experimental data. It is found that the Weinberg-Tomozawa potential derived from the lowest order chiral Lagrangian only provides the contributions from partial waves with spin-parities $J^{P} = 1/ 2^{+}$ and $1/ 2^{-}$ . Two-pole structure of the $Λ (1405)$ is confirmed with poles at $1383 + 99 i$ and $1423 + 14 i$ MeV. The lower and higher poles originate from $Σ π$ interaction as a resonance and $K ˉ N$ interaction as a bound state, respectively.
Comments:
13 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1510.00580 [pdf]
IJMPE(2015)·18 citations
08
[Submitted on 2 Oct 2015]
The baryon spectrum and the hypercentral Constituent Quark Model
M.M. Giannini🇮🇹 · E. Santopinto🇮🇹
The description of the baryon spectrum is performed using the hypercentral Consituent Quark Model (hCQM), mainly in comparison with the harmonic oscillator (h.o.). Recentlly many new states, at various levels of confidence have been observed, leading to a softening of the missing resonance problem in the case of positive parity states. However, the number of negative states is higher that predicted by the commonly used h.o. scheme and therefore one is forced to take into account also the higher energy shells, which contain an overall number of states much greater than the observed one. It is shown that, thanks to the peculiar level scheme of the hCQM, the recently observed negative parity states can be considered as belonging to the lower shells, keeping the missing resonance problem within more acceptable limits.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1510.00582 [pdf]
4 citations

Affiliations

first authorsco-authorsvia INSPIRE