Constraints on the nuclear symmetry energy and its density slope from the ${\boldsymbol{\alpha }}$ decay process

Abstract

We study the impact of the nuclear symmetry energy and its density dependence on the α-decay process. Within the frame work of the performed cluster model and the energy density formalism, we use different parameterizations of the Skyrme energy density functionals that yield different equations of state EOSs. Each EOS is characterized by a particular symmetryenergy coefficient (a sym ) and a corresponding density-slope parameters L. The stepwise trends of the neutron (proton) skin thickness of the involved nuclei with both a sym and L do not clarify the obtained oscillating behaviors of the αdecay half-life T α with them. We find that the change of the skin thickness after α-decay satisfactory explains these behaviors. The presented results provide constrains on a sym centered around an optimum value a sym = 32 MeV, and on L between 41 and 57 MeV. These values of a sym and L, which indicate larger reduction of the proton-skin thickness and less increase in the neutron-skin thickness after an α-decay, yield minimum calculated half-life with the same extracted value of the α-preformation factor inside the parent nucleus.PACS number(s): 23.60.+e, 21.60.Jz, 21.65.Mn, 21.10.Gv, 21.65.Ef

Hindrance factors of unfavored α decay transitions to duplicated daughter states of the same spin and parity

“…For the unfavored decay modes, the redial dependence of the centrifugal part of the potential is considered in its ordinary form, V ℓ (r) = ℓ (ℓ + 1) 2 /2µr 2 . We shall consider the Hamiltonian energy density formalism [32] based on the Skyrme-SLy4 [33] NN interaction to calculate the nuclear part of the potential [5,18,34],…”

“…The α-decay observables have shown great value in re ning our understanding of diverse nuclear structure properties, like the nuclear density distributions and their static deformations, nuclear radii, the proton and neutron skins, the pairing and shell effects, and the spin-parity con gurations of nuclei in their ground and excited states [9][10][11][12][13]. Also, the α decays have been used to get information on the nuclear equation of state and its related quantities such as the symmetry energy and incompressibility, and their isospin asymmetry dependence [14][15][16][17][18]. The inevitable conservation rules of angular momentum and parity that govern the nuclear decays and the rearrangement of single-particle orbits limit the possible α transitions to the different daughter states that can be populated.…”

Mass–radius relation of neutron stars and massive pulsars with realistic equation of state

“…Thus, significant advancements have come from astrophysical observations of NS to probe the EOS at high compact densities. Data of finite nuclei and terrestrial experiments cannot reach such high density, they can be used to probe the EOS for densities less than double the saturation density [23][24][25]. Although the effective-field theory techniques and quantum chromodynamics serve as a solid guide for theoretical work [26,27], we still have uncertainty and unclear answers of a few questions regarding the knowledge of the accurate structure of NS and of their core composition [7].…”

Impact of different components of the Skyrme nucleon-nucleon effective interaction on the nuclear density distribution

“…Each Skyrme parameterization is characterized by definite NM properties, such as symmetry energy and its density slope, incompressibility, and effective mass. The effective NN interactions in the form of Skyrme energydensity functionals successfully allowed the semi-microscopic self-consistent description of nuclear structure [19][20][21][22][23], reactions [9,[24][25][26], and decays [27][28][29][30][31], as well as nuclear matter properties [32][33][34] and astrophysical phenomena [35,36] investigations. It has been applied extensively in mean-field studies for several decades.…”