Nuclear Theory·nucl-th

Monday·December 22, 2014

11 papers—5 primary·6 cross-listed

01
Nucleon resonances in the $γ p \to ϕ K^{+} Λ$ reaction near threshold
Qi-Fang Lü🇨🇳 · Rong Wang🇨🇳 · Ju-Jun Xie🇨🇳 · Xu-Rong Chen🇨🇳 · De-Min Li🇨🇳
We investigate the $γ p \to ϕ K^{+} Λ$ reaction near threshold within an effective Lagrangian approach and the isobar model. Various nucleon resonances caused by the $π$ and $η$ meson exchanges and background contributions are considered. It is shown that the contribution from the $N^{*} (1535)$ resonance caused by the $η$ meson exchange plays the predominant role. Hence, this reaction provides a good new platform to study the $N^{*} (1535)$ resonance. The predicted total cross section and specific features of angular distributions can be tested by future experiments.
nucl-thhep-phnucl-exPRC(2015)·17 citations
02
Baryon onset in a magnetic field
Alexander Haber🇦🇹 · Florian Preis🇦🇹 · Andreas Schmitt🇦🇹
The critical baryon chemical potential for the onset of nuclear matter is a function of the vacuum mass and the binding energy. Both quantities are affected by an external magnetic field. We show within two relativistic mean-field models - including magnetic catalysis, but omitting the anomalous magnetic moment - that a magnetic field increases both the vacuum mass and the binding energy. For sufficiently large magnetic fields, the effect on the vacuum mass dominates and as a result the critical baryon chemical potential is increased.
nucl-thhep-phAIP Conf.Proc.(2016)·7 citations
03
Computational approaches to many-body dynamics of unstable nuclear systems
Alexander Volya
The goal of this presentation is to highlight various computational techniques used to study dynamics of quantum many-body systems. We examine the projection and variable phase methods being applied to multi-channel problems of scattering and tunneling; here the virtual, energy-forbidden channels and their treatment are of particular importance. The direct time-dependent solutions using Trotter-Suzuki propagator expansion provide yet another approach to exploring the complex dynamics of unstable systems. While presenting computational tools, we briefly revisit the general theory of the quantum decay of unstable states. The list of questions here includes those of the internal dynamics in decaying systems, formation and evolution of the radiating state, and low-energy background that dominates at remote times. Mathematical formulations and numerical approaches to time-dependent problems are discussed using the quasi-stationary methods involving effective Non-Hermitian Hamiltonian formulation.
nucl-th3 citations
04
Minimally non-local nucleon-nucleon potentials with chiral two-pion exchange including $Δ$ 's
M. Piarulli🇺🇸 · L. Girlanda🇮🇹 · R. Schiavilla🇺🇸 · R. Navarro Pérez🇪🇸 · J.E. Amaro🇪🇸 · E. Ruiz Arriola🇪🇸
We construct a coordinate-space chiral potential, including $Δ$ -isobar intermediate states in its two-pion-exchange component. The contact interactions entering at next-to-leading and next-to-next-to-next-to-leading orders ( $Q^{2}$ and $Q^{4}$ , respectively, $Q$ denoting generically the low momentum scale) are rearranged by Fierz transformations to yield terms at most quadratic in the relative momentum operator of the two nucleons. The low-energy constants multiplying these contact interactions are fitted to the 2013 Granada database, consisting of 2309 $pp$ and 2982 $n p$ data (including, respectively, 148 and 218 normalizations) in the laboratory-energy range 0--300 MeV. For the total 5291 $pp$ and $n p$ data in this range, we obtain a $χ^{2}$ /datum of roughly 1.3 for a set of three models characterized by long- and short-range cutoffs, $R_{L}$ and $R_{S}$ respectively, ranging from $(R_{L}, R_{S}) = (1.2, 0.8)$ fm down to $(0.8, 0.6)$ fm. The long-range (short-range) cutoff regularizes the one- and two-pion exchange (contact) part of the potential.
nucl-thPRC(2015)·228 citations
05
The Neutrino Opacity of Neutron Star Inner Crust
P. N. Alcain · C. O. Dorso
The study of neutron rich matter, present in neutron star, proto-neutron stars and core-collapse supernovae, can lead to further understanding of the behavior of nuclear matter in highly asymmetric nuclei. Heterogeneous structures are expected to exist in these systems, often referred to as nuclear pasta. We have carried out a systematic study of neutrino opacity for different thermodynamic conditions in order to assess the impact that the structure has on it. We studied the dynamics of the neutrino opacity of the heterogeneous matter at different thermodynamic conditions with semiclassical molecular dynamics model already used to study nuclear multifragmentation. For different densities, proton fractions and temperature, we calculate the very long range opacity and the cluster distribution. The neutrino opacity is of crucial importance for the evolution of the core-collapse supernovae and the neutrino scattering.
nucl-thNPA(2017)·11 citations

Affiliations

first authorsco-authorsvia INSPIRE

Nucleon resonances in the γp→ϕK+Λ reaction near threshold

Baryon onset in a magnetic field

Computational approaches to many-body dynamics of unstable nuclear systems

Minimally non-local nucleon-nucleon potentials with chiral two-pion exchange including Δ's

The Neutrino Opacity of Neutron Star Inner Crust

Affiliations

Nucleon resonances in the $γ p \to ϕ K^{+} Λ$ reaction near threshold

Minimally non-local nucleon-nucleon potentials with chiral two-pion exchange including $Δ$ 's