Nuclear Theory·nucl-th

Friday·July 26, 2024

13 papers—6 primary·7 cross-listed

01
Resonances and collisional properties of neutron-rich helium isotopes in the adiabatic hyperspherical representation
Michael D. Higgins · Chris H. Greene
This work treats few-body systems consisting of neutrons interacting with a $^{4} He$ nucleus. The adiabatic hyperspherical representation is utilized to solve the $N$ -body Schr $o ¨$ dinger equation for the three- and four-body systems, treating both $^{6} He$ and $^{7} He$ nuclei. A simplified central potential model for the $^{4} He - n$ interaction is used in conjunction with a spin-dependent three-body interaction to reproduce $^{6} He$ bound-state and resonance properties as well as properties for the $^{8} He$ nucleus in its ground-state. With this Hamiltonian, the adiabatic hyperspherical representation is used to compute bound and scattering states for both $^{6} He$ and $^{7} He$ nuclei. For the $^{6} He$ system, the electric quadrupole transition between the $0^{+}$ and $2^{+}$ state is investigated. For the $^{7} He$ system, $^{6} He + n$ elastic scattering is investigated along with the four-body recombination process $^{4} He + n + n + n \to$ $^{6} He + n$ and breakup process $^{6} He + n \to$ $^{4} He + n + n + n$ .
nucl-thquant-phPRC(2025)·2 citations
02
Heavy-flavor mesons in a strong electric field
Jiayun Xiang🇨🇳 · Gaoqing Cao🇨🇳
Very strong electromagnetic field can be generated in peripheral relativistic heavy ion collisions. This work is devoted to exploring the interplay between the effects of a constant external electric field and confining potential on heavy-flavor mesons. As the corresponding vector potential linearly depends on one spatial coordinate for a constant electric field, it might be able to overcome the linear confining potential of QCD and induce deconfinement. To perform analytic calculations and for comparison, one and two dimensional systems are studied together with the realistic three dimensional systems. The one dimensional Schr $o ¨$ dinger equation can be solved analytically with the help of Airy functions, and deconfinement is indeed realized when the electric field is larger than the string tension. Focus on the confining case, the two and three dimensional Schr $o ¨$ dinger equations can be solved analytically in large $r$ limit with the help of elliptic cosine/sine functions, and the wave functions are dominated by the region antiparallel to the electric field. When a more realistic potential is applied, a non-monotonic feature is found for $Υ (2 S)$ and $Υ (3 S)$ -like mesons with increasing electric field.
nucl-thhep-phPRD(2024)·2 citations
03
Probing coalescence of light nuclei via femtoscopy and azimuthal anisotropies
Yoshini Bailung🇮🇳 · Sudhir Pandurang Rode🇷🇺 · Neha Shah🇮🇳 · Ankhi Roy🇮🇳
The production mechanism of light nuclei in heavy-ion collisions is vital to understanding the intricate details of nucleon-nucleon interactions. The coalescence of nucleons is a well-known mechanism that attempts to explain the production mechanism of these light clusters. This work investigates the formation mechanism of these nucleon clusters with a combination of coalescence and femtoscopy of nucleons and nuclei. It is achieved by appending a coalescence and correlation afterburner (\texttt{CRAB}) to the \texttt{SMASH} transport model. To have a proper view of the anisotropy of light nuclei clusters, a mean-field approach to \texttt{SMASH} is applied. The anisotropic coefficients of various light nuclei clusters are calculated and compared to experimental measurements. To incorporate hydrodynamics into the picture, the anisotropic measurements are completed in a hybrid \texttt{SMASH}+\texttt{vHLLE} mode. In both approaches, the femtoscopy of nucleons and light nuclei is performed, reported with CRAB, and compared to the latest experimental measurements. An insight into cluster formation time is drawn by extracting the emission source size with the Lednický-Lyuboshits (LL) model.
nucl-thhep-phPRC(2025)·2 citations
04
Dimensionality reduction through tensor factorization : application to \textit{ab initio} nuclear physics calculations
Mikael Frosini · Thomas Duguet · Pierre Tamagno · Lars Zurek
The construction of predictive models of atomic nuclei from first principles is a challenging (yet necessary) task towards the systematic generation of theoretical predictions (and associated uncertainties) to support nuclear data evaluation. The consistent description of the rich phenomenology of nuclear systems indeed requires the introduction of reductionist approaches that construct nuclei directly from interacting nucleons by solving the associated quantum many-body problem. In this context, so-called \textit{ab initio} methods offer a promising route by deriving controlled (and systematically improvable) approximations both to the inter-nucleon interaction and to the solutions of the many-body problem. From a technical point of view, approximately solving the many-body Schrödinger equation in heavy open-shell systems typically requires the construction and contraction of large mode-4 (mode-6) tensors that need to be stored repeatedly. Recently, a new dimensionality reduction method based on randomized singular value decomposition has been introduced to reduce the numerical cost of many-body perturbation theory. This work applies this lightweight formalism to the study of the Germanium isotopic chain, where standard approaches would be too expansive to run. Inclusion of triaxiality is found to improve the overall agreement with experimental data on differential quantities.
nucl-thEPJ Web Conf.(2024)·1 citation
05
Alpha-decay from $^{44}$ Ti: Microscopic alpha half-life calculation using normalized spectroscopic factor
A. C. Dassie · R. M. Id Betan
The microscopic description of alpha decay from the nucleons' degree of freedom involves a two-step process. The first consists of the clusterization of neutron and proton pairs; the second involves the tunneling process. A robust protocol for calculating the normalized spectroscopic factor, as defined by Fliessbach, and its error is established and used for calculating the alpha-width for the $0^{+}$ states of the nucleus $^{44}$ Ti. The Gamow Shell Model is used to calculate the structure part of the alpha-decay, while the Gamow wave function determines the reaction part. The conventional and normalized spectroscopic factors are calculated for the ground and excited $0^{+}$ states of $^{44}$ Ti and the alpha-width and half-life of the excited states. A near alpha-threshold state has an alpha half-life of 5 $μ$ sec. The normalization does not appreciably modify the ground-state clusterization, while the excited states do. The non-resonant continuum significantly increases the clustering of some of the excited states, particularly the $T = 2$ state. The normalized formation amplitude looks like a single-particle wave function.
nucl-thPRC(2024)·0 citations
06
Determination of the proton spectral function of \isotope[12][]{C} from $(e, e^{'} p)$ data
Artur M. Ankowski🇵🇱 · Omar Benhar🇮🇹 · Makoto Sakuda🇯🇵
The determination of the nuclear spectral function from the measured cross section of the electron-nucleus scattering process $e + A \to e^{'} + p + (A - 1)$ is discussed, and illustrated for the case of a carbon target. The theoretical model based on the local density approximation, previously employed to derive the spectral function from a combination of accurate theoretical calculations and experimental data, has been developed further by including additional information obtained from measurements performed with high missing energy resolution. The implications for the analysis of $γ$ -ray emission associated with nuclear deexcitation are considered.
nucl-thhep-phPRC(2024)·18 citations

Affiliations

first authorsco-authorsvia INSPIRE

Resonances and collisional properties of neutron-rich helium isotopes in the adiabatic hyperspherical representation

Heavy-flavor mesons in a strong electric field

Probing coalescence of light nuclei via femtoscopy and azimuthal anisotropies

Dimensionality reduction through tensor factorization : application to \textit{ab initio} nuclear physics calculations

Alpha-decay from 44Ti: Microscopic alpha half-life calculation using normalized spectroscopic factor

Determination of the proton spectral function of \isotope[12][]{C} from (e,e′p) data

Affiliations

Alpha-decay from $^{44}$ Ti: Microscopic alpha half-life calculation using normalized spectroscopic factor

Determination of the proton spectral function of \isotope[12][]{C} from $(e, e^{'} p)$ data