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Nuclear Theory·nucl-th

Friday·May 28, 2021

8 papers—4 primary·4 cross-listed

All8Primary4Cross-lists4
  1. 01

    Predictions for flow harmonic distributions and flow factorization ratios at RHIC

    Leonardo Barbosa🇧🇷 · Fernando G. Gardim🇧🇷 · Frédérique Grassi🇧🇷 · Pedro Ishida🇧🇷 · Matthew Luzum🇧🇷 · Meera V. Machado🇩🇰 · Jacquelyn Noronha-Hostler🇺🇸

    Data obtained at RHIC can be reproduced with relativistic viscous hydrodynamic simulations by adjusting the viscosity and initial conditions but it is difficult to disentangle these quantities. It is therefore important to find orthogonal observables to constrain the initial conditions separately from the viscosity. New observables have been measured at the LHC and shown to be sensitive to initial conditions and less to medium properties, specifically factorization breaking ratios appears to be promising. Here we consider two initial condition models, NeXus and TRENTO. While both models yield similar results for the scaled flow harmonic distributions both at the LHC and RHIC, they lead to quantitatively much more different patterns for the factorization breaking ratios at RHIC than at LHC, due to the shorter lifetime. Additionally, not only final state interactions but also initial free streaming matter in these ratio predictions and differences between these are enhanced at RHIC compared to LHC. Therefore experimental factorization breaking ratios at RHIC top energy (for transverse momentum) would be interesting to get.

    nucl-thnucl-ex13 citations
  2. 02

    Nuclear superfluidity at finite temperature

    Elena Litvinova🇺🇸 · Peter Schuck🇫🇷

    The equation of motion for the two-fermion two-time correlation function in the pairing channel is considered at finite temperature. Within the Matsubara formalism, the Dyson-type Bethe-Salpeter equation (Dyson-BSE) with the frequency-dependent interaction kernel is obtained. Similarly to the case of zero temperature, it is decomposed into the static and dynamical components, where the former is given by the contraction of the bare interaction with the two-fermion density and the latter is represented by the double contraction of the four-fermion two-time correlation function, or propagator, with two interaction matrix elements. The dynamical kernel with the four-body propagator, being formally exact, requires approximations to avoid generating prohibitively complicated hierarchy of equations. We focus on the approximation where the dynamical interaction kernel is truncated on the level of two-body correlation functions, neglecting the irreducible three-body and higher-rank correlations. Such a truncation leads to the dynamical kernel with the coupling between correlated fermionic pairs, which can be interpreted as emergent bosonic quasibound states, or phonons, of normal and superfluid nature. The latter ones are, thus, the mediators of the dynamical superfluid pairing. In this framework, we obtained the closed system of equations for the fermionic particle-hole and particle-particle propagators. This allows us to study the temperature dependence of the pairing gap beyond the Bardeen-Cooper-Schrieffer approximation, that is implemented for medium-heavy nuclear systems. The cases of 68Ni and 44,46Ca are discussed in detail.

    nucl-thcond-mat.supr-conPRC(2021)·12 citations
  3. 03

    Benchmarking Many-body Approaches for the Determination of Isotope Shift Constants: Application to the Li, Be and Ar Isoelectronic Systems

    B. K. Sahoo · B. Ohayon

    We have applied relativistic coupled-cluster (RCC) theory to determine the isotope shift (IS) constants of the first eight low-lying states of the Li, Be and Ar isoelectronic systems. Though the RCC theory with singles, doubles and triples approximation (RCCSDT method) is an exact method for these systems for a given set of basis functions, we notice large differences in the results from this method when various procedures in the RCC theory framework are adopted to estimate the IS constants. This has been demonstrated by presenting the IS constants of the aforementioned states from the finite-field, expectation value and analytical response (AR) approaches of the RCCSDT method. Contributions from valence triple excitations, Breit interaction and lower-order QED effects to the evaluation of these IS constants are also highlighted. Our results are compared with high-precision calculations reported using few-body methods wherever possible. We find that results from the AR procedure are more reliable than the other two approaches. This analysis is crucial for understanding the roles of electron correlation effects in the accurate determination of IS constants in the heavier atomic systems, where few-body methods cannot be applied.

    nucl-thphysics.atom-phphysics.comp-phPRA(2021)·10 citations
  4. 04

    Correlations between nuclear landscape boundaries and neutron-rich r-process abundances

    Q.Z. Chai · Y. Qiang · J.C. Pei

    Motivated by the newly observed Na in experiments, systematic calculations of global nuclear binding energies with seven Skyrme forces are performed. We demonstrate the strong correlation between the two-neutron separation energies () of Na and the total number of bound nuclei of the whole nuclear landscape. Furthermore, with calculated nuclear masses, we perform astrophysical rapid-neutron capture process (-process) simulations by using nuclear reaction code TALYS and nuclear reaction network code SkyNet. -process abundances from ejecta of neutron star mergers and core-collapse supernova are compared. Prominent covariance correlations between nuclear landscape boundaries and neutron-rich -process abundances before the third peak are shown. This study highlights the needs for further experimental studies of drip-line nuclei around Na for better constraints on nuclear landscape boundaries and -process.

    nucl-thPRC(2022)·12 citations

Affiliations

first authorsco-authorsvia INSPIRE