Nuclear Theory·nucl-th

Thursday·July 6, 2023

12 papers—5 primary·7 cross-listed

01
How to extract the electromagnetic response of $^{6}$ He in relativistic collisions
C.A. Bertulani
I investigate the difficulties in obtaining the electromagnetic response of light, halo-like, nuclei using reactions at radioactive beam facilities. A relativistic coupled-channels theory for the calculation of dissociation cross sections of halo nuclei is compared to first-order perturbation theory. A comparison with semiclassical models frequently used in experimental analysis is also performed. It is shown that the effects of relativity and of the nuclear interaction lead to sizable effects in the extraction of the electromagnetic response of 6He projectiles.
nucl-thnucl-exPRC(2023)·4 citations
02
Cluster decay dynamics of Actinides yielding non-Pb-daughter
Joshua T. Majekodunmi · M. Bhuyan · Raj Kumar
The cluster dynamics of radioactive nuclei decaying to neighbouring daughter nuclei of the double magic $^{132}$ Sn and $^{208}$ Pb is investigated using the relativistic mean-field (RMF) approach with NL3 $^{*}$ parameter set within the preformed cluster-decay model (PCM). The novel feature of the present study is the application of the newly derived preformation formula, laying the groundwork for accessing the break-up of the Q-value: preformation energy, cluster emission energy and the recoil energy of the daughters formed. The energy associated with cluster preformation is theoretically quantified for the first time. This treatment underscores the shell effect, pairing correlation as well as the blocking of particular orbitals by unpaired nucleons. To ascertain the applicability of the new formula, the PCM based calculations are carried out with nuclear potential obtained using the phenomenological M3Y and microscopic RMF-based R3Y nucleon-nucleon (NN) potentials along with corresponding densities. We found a marginal variation that can be attributed to the difference in their barrier properties, however, the predictions for the case of both M3Y and R3Y potentials are found to agree well with the experimental half-lives. Although none of the considered reaction systems yields a double magic daughter nucleus, we found that the kinematics of their cluster emissions is governed by their proximity to the shell closure. The deduced systematic of the recoil energy in cluster decays can provide valuable insight for the synthesis of elements in superheavy mass region in the future.
nucl-thEPJA(2024)·3 citations
03
Reaction dynamics in clustered nuclear systems
Salvatore Simone Perrotta
This work is concerned with the theoretical study of nuclear reactions between light charged ions at incident energies around and below the reactants Coulomb barrier, with a focus on the energy range of astrophysical interest for Big Bang and quiescent stellar processes. The main goal of the analysis is to investigate the sensitivity of nuclear reaction dynamics, and more specifically the cross-section predictions, to the description of the structure of each reactant, and in particular to clustering phenomena. The case of the $^{6}$ Li + p $\to$ $^{3}$ He + $^{4}$ He reaction was investigated explicitly, treating the process as a direct deuteron transfer in first- or second-order distorted-wave Born approximation and through a coupled-reaction-channels approach. The penetrability of the Coulomb barrier in the initial state was also analysed phenomenologically from available experimental data, and studied theoretically taking into account the $^{6}$ Li ground-state deformation.
nucl-th3 citations
04
Laser-assisted deformed $α$ decay of the ground state even-even nuclei
Jun-Hao Cheng · Wen-Yu Zhang · Qiong Xiao · Jun-Gang Deng · Tong-Pu Yu
In the present work, the influence of ultra-intense laser fields on the $α$ decay half-life of the deformed ground state even-even nucleus with the mass number $52 \leq Z \leq 118$ is systematically studied. The calculations show that the laser field changes the $α$ decay half-life by varying the $α$ decay penetration probability in a small range. Moreover, the analytical formulas for the rate of change of the $α$ decay penetration probability in the ultra-intense laser fields have been derived by the spherical approximation, which agrees well with the numerical solutions for nuclei with more significant proton numbers. This provides a fast way to estimate the rate of change of the $α$ decay penetration probability for superheavy nuclei. Furthermore, the relationship between laser properties and the average rate of change of the $α$ decay penetration probability is investigated. The calculations indicate that the shorter the wavelength of the laser pulse is, the larger the average rate of change of the penetration probability.
nucl-thNucl.Sci.Tech.(2025)·8 citations
05
Collision integral with momentum-dependent potentials and its impact on pion production in heavy-ion collisions
Natsumi Ikeno🇯🇵 · Akira Ono🇯🇵
The momentum dependence of the nucleon mean-field potential in a wide momentum range can be an important factor to determine the $Δ$ resonance and pion production in intermediate-energy heavy-ion collisions. In particular, in neutron-rich systems such as $^{132} Sn +^{124} Sn$ collisions, we need to carefully treat the momentum dependence because the neutron and proton potentials can have different momentum dependence, as characterized at low momenta by effective masses. In the present work, we rigorously calculate the collision terms of $N N \leftrightarrow N Δ$ and $Δ \leftrightarrow N π$ processes with the precise conservation of energy and momentum under the presence of momentum-dependent potentials for the initial and final particles of the process. The potentials affect not only the threshold condition for the process but also the cross section in general as a function of the momenta of the initial particles, which is treated in a natural way in the present work. Calculations are performed by combining the nucleon dynamics obtained by the antisymmetrized molecular dynamics (AMD) model with a newly developed transport code which we call sJAM. The calculated results for central $^{132} Sn +^{124} Sn$ collisions at 270 MeV/nucleon clearly show that the momentum dependence of the neutron and proton potentials has a significant impact on the $N N \to N Δ$ process, and this information is strongly reflected in the charged pion ratio ( $π^{-} / π^{+}$ ). We also investigate the effects of the high-density symmetry energy and the isovector part of the potential of $Δ$ resonances on pion production, which we find are relatively small compared to the effect of the momentum dependence of the neutron and proton potentials.
nucl-thnucl-exPRC(2023)·13 citations

Affiliations

first authorsco-authorsvia INSPIRE

How to extract the electromagnetic response of 6He in relativistic collisions

Cluster decay dynamics of Actinides yielding non-Pb-daughter

Reaction dynamics in clustered nuclear systems

Laser-assisted deformed α decay of the ground state even-even nuclei

Collision integral with momentum-dependent potentials and its impact on pion production in heavy-ion collisions

Affiliations

How to extract the electromagnetic response of $^{6}$ He in relativistic collisions

Laser-assisted deformed $α$ decay of the ground state even-even nuclei