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Nuclear Theory·nucl-th

Friday·June 30, 2017

10 papers—4 primary·6 cross-listed

All10Primary4Cross-lists6
  1. 01

    Lambda hyperon polarization in relativistic heavy ion collisions from the chiral kinetic approach

    Yifeng Sun🇺🇸 · Che Ming Ko🇺🇸

    Based on the chiral kinetic approach using initial conditions from a multiphase transport model, we study the spin polarizations of quarks and antiquarks in non-central heavy ion collisions at the Relativistic Heavy Ion Collider. Because of the non-vanishing vorticity field in these collisions, quarks and antiquarks are found to acquire appreciable spin polarizations in the direction perpendicular to the reaction plane. Converting quarks and antiquarks to hadrons via the coalescence model, we further calculate the spin polarizations of Lambda and anti-Lambda hyperons and find their values comparable to those measured in experiments by the STAR Collaboration.

    nucl-thPRC(2017)·175 citations
  2. 02

    New successive variational method of tensor-optimized antisymmetrized molecular dynamics for nuclear many-body systems

    Takayuki Myo🇯🇵 · Hiroshi Toki🇯🇵 · Kiyomi Ikeda🇯🇵 · Hisashi Horiuchi🇯🇵 · Tadahiro Suhara🇯🇵

    We recently proposed a new variational theory of "tensor-optimized antisymmetrized molecular dynamics" (TOAMD), which treats the strong interaction explicitly for finite nuclei [T. Myo et al., Prog. Theor. Exp. Phys. 2015, 073D02 (2015)]. In TOAMD, the correlation functions for the tensor force and the short-range repulsion and their multiple products are successively operated to the AMD state. The correlated Hamiltonian is expanded into many-body operators by using the cluster expansion and all the resulting operators are taken into account in the calculation without any truncation. We show detailed results for TOAMD with the nucleon-nucleon interaction AV8 for -shell nuclei. The binding energy and the Hamiltonian components are successively converged to exact values of the few-body calculations. We also apply TOAMD to the Malfliet-Tjon central potential having a strong short-range repulsion. TOAMD can treat the short-range correlation and provided accurate energies of -shell nuclei, reproducing the results of few-body calculations. It turns out that the numerical accuracy of TOAMD with double products of the correlation functions is beyond the variational Monte Carlo method with Jastrow's product-type correlation functions.

    nucl-thPTEP(2017)·17 citations
  3. 03

    Structural effects of Na in the Na(n,Na radiative capture reaction

    G. Singh🇮🇳 · Shubhchintak🇺🇸 · R. Chatterjee🇮🇳

    The path towards the production of \textit{r}-process seed nuclei follows a course where the neutron-rich light and medium mass nuclei play a crucial role. The neutron capture rates for these exotic nuclei could dominate over their -capture rates, thereby enhancing their abundances at or near the drip line. We calculate the radiative neutron capture cross-section for the Na(n,Na reaction via the Coulomb dissociation of Na as it undergoes elastic breakup on Pb when directed at a beam energy of 100 MeV/u using the entirely quantum mechanical theory of finite range distorted wave Born approximation upgraded to incorporate deformation effects. The non-resonant one neutron radiative capture cross-section for Na(n,Na is calculated and is found to increase with increasing deformation of Na. An analytic scrutiny of the capture cross-section with neutron separation energy as a parameter is also done at different energy ranges. The calculated reaction rate is compared with the rate of the Na(,n)Al reaction (deduced from the Hauser-Feshbach theory), and is found to be significantly higher below a temperature of . Further, at the equilibrium temperature of , the rate for the neutron capture had a small but non-negligible dependence on the structural parameters of Na. In addition, this neutron capture rate exceeded that of the -capture reaction by orders of magnitude, indicating that the -process should not break the (n,) \textit{r-}process path at the Na isotope, thus, effectively pushing the abundance of sodium isotopes towards the neutron drip line.

    nucl-thPRC(2017)·16 citations
  4. 04

    The in neutron stars - a new degree of freedom?

    I. Vidaña🇵🇹 · M. Bashkanov🇬🇧 · D.P. Watts🇬🇧 · A. Pastore🇬🇧

    Elucidating the appropriate microscopic degrees of freedom within neutron stars remains an open question which impacts nuclear physics, particle physics and astrophysics. The recent discovery of the first non-trivial dibaryon, the , provides a new candidate for an exotic degree of freedom in the nuclear equation of state at high matter densities. In this paper a first calculation of the role of the in neutron stars is performed, based on a relativistic mean field description of the nucleonic degrees of freedom supplemented by a free boson gas of . The calculations indicate that the would appear at densities around three times normal nuclear matter saturation density, influencing the upper mass limit for a stable neutron star and the neutron and proton fractions. New possibilities for neutron star cooling mechanisms arising from the are also predicted.

    nucl-thastro-ph.HEPLB(2018)·38 citations

Affiliations

first authorsco-authorsvia INSPIRE