Nuclear Theory·nucl-th

Wednesday·July 6, 2022

9 papers—5 primary·4 cross-listed

01
[Submitted on 4 Jul 2022]
Cluster folding analysis for the 6,7Li and 20Ne + 24Mg nuclear systems
Sh. Hamada
The experimentally available angular distributions (ADs) for 6,7Li and 20Ne ions elastically scattered from a 24Mg target are reanalyzed using various nuclear potentials based on phenomenological and microscopic approaches. The ADs for the 6Li + 24Mg system at energies Elab = 20, 88, and 240 MeV are considered, as are the ADs for the 7Li + 24Mg system at Elab = 20, 34, and 88 MeV, and the ADs for the 20Ne + 24Mg systems at Elab = 50, 60, 80, 90, and 100 MeV. Special emphasis is placed on the (d + {\alpha}) and (t + {\alpha}) cluster structures of 6Li and 7Li weakly bound projectiles, which appear at relatively low energies of 1.4737 and 2.468 MeV, respectively. Furthermore, the 20Ne stable nucleus is a candidate to reveal the {\alpha} + 16O cluster structure at an energy of 4.73 MeV. These systems are analyzed within the framework of the cluster folding model by taking into consideration the aforementioned cluster nature of the (6Li, 7Li, and 20Ne) projectiles. The adopted approaches fairly reproduced the experimental ADs.
Comments:
17 pages, 12 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2207.01741 [pdf]
0 citations
02
[Submitted on 5 Jul 2022]
Covariant Density Functional Theory with Localized Exchange Terms
Qiang Zhao · Zhengxue Ren · Pengwei Zhao · Jie Meng
A new density-dependent point-coupling covariant density functional PCF-PK1 is proposed, where the exchange terms of the four-fermion terms are local and are taken into account with the Fierz transformation. The coupling constants of the PCF-PK1 functional are determined by empirical saturation properties and ab initio equation of state and proton-neutron Dirac mass splittings for nuclear matter as well as the ground-state properties of selected spherical nuclei. The success of the PCF-PK1 is illustrated with properties of the infinite nuclear matter and finite nuclei including the ground-state properties and the Gamow-Teller resonances. In particular, the PCFPK1 eliminates the spurious shell closures at Z = 58 and Z = 92, which exist commonly in many covariant density functionals without exchange terms. Moreover, the Gamow-Teller resonances are nicely reproduced without any adjustable parameters, and this demonstrates that a self-consistent description for the Gamow-Teller resonances can be achieved with the localized exchange terms in the PCF-PK1. ?
Comments:
35 pages, 14 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2207.01764 [pdf]
PRC(2022)·26 citations
03
[Submitted on 5 Jul 2022]
Nuclear incompressibility and sound speed in uniform matter and finite nuclei
Guilherme Grams🇫🇷 · Rahul Somasundaram🇫🇷 · Jerome Margueron🇫🇷 · Elias Khan🇫🇷
We have extended the compressible liquid-drop model (CLDM) with a density-dependent surface term (eCLDM), which allows for a unified description of both the nuclear ground state energies and the incompressibility modulus in finite nuclei $K_{A}$ . We analyse the role of the nuclear empirical parameters, e.g., $K_{s a t}$ , $Q_{s a t}$ , $L_{sy m}$ and $K_{sy m}$ , which contribute to the bulk properties, as well as the role of the finite size contributions. For the bulk properties, the density and isospin dependencies of the nuclear incompressibility in infinite matter are characterized by introducing new empirical parameters, and two new constraints for the value of $K_{sy m}$ are suggested. For finite nuclei, we employ a Bayesian approach coupled to a Markov-Chain Monte-Carlo (MCMC) exploration of the parameter space to confront the model predictions of $K_{A}$ in Zr, Sn and Pb isotopes to the experimental data. We show that $Q_{s a t} \approx - 950 \pm 200$ ~MeV describes the experimental measurements of $K_{A}$ in these isotopes. This value is different from the ones deduced from phenomenological nuclear energy density functionals, suggesting a possible explanation of their difficulty to accurately describe Zr, Sn and Pb data all together. In addition we explore the impact of a fictitious measurement of the Giant Monopole Resonance energy in $^{132}$ Sn. We show that this measurement, provided it is accurate enough, will allow to better determine $K_{sy m}$ and $K_{τ}$ . Finally we explore the properties of the sound speed around saturation density and show the important role of finite size terms in finite nuclei since they reduce the sound speed to approximately half compared to nuclear matter.
Comments:
21 pages, 12 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2207.01884 [pdf]
PRC(2022)·23 citations
04
[Submitted on 5 Jul 2022]
Final state interactions in semi-inclusive neutrino-nucleus scattering: Application to T2K and MINER $ν$ A experiments
J.M. Franco-Patino🇪🇸 · R. González-Jiménez🇮🇹 · S. Dolan🇨🇭 · M.B. Barbaro🇮🇹 · J.A. Caballero🇪🇸 · G.D. Megias🇪🇸 · J.M. Udias🇮🇹
We present a complete comparison of semi-inclusive $ν_{μ}$ - $^{12}$ C cross-section measurements by T2K and MINER $ν$ A collaborations with the predictions from the SuSAv2-MEC model implemented in the neutrino-nucleus event generator GENIE and an unfactorized approach based on the relativistic distorted wave impulse approximation (RDWIA). Results, that include cross sections as function of the final muon and proton kinematics and correlations between both, show that the agreement with data obtained by the RDWIA approach, that accounts for final-state interactions, matches or improves GENIE-SuSAv2 predictions for very forward angles where scaling violations are relevant.
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2207.02086 [pdf]
PRD(2022)·41 citations
05
[Submitted on 5 Jul 2022]
Solving the matrix exponential function for the groups SU(3), SU(4) and Sp(2)
Norbert Kaiser
The well known analytical formula for $S U (2)$ matrices $U = exp (i τ \cdot φ) = cos ∣ φ ∣ + i τ \cdot φ^sin ∣ φ ∣$ \\ is extended to the $S U (3)$ group with eight real parameters. The resulting analytical formula involves the sum over three real roots of a cubic equation, corresponding to the so-called irreducible case, where one has to employ the trisection of an angle. When going to the special unitary group $S U (4)$ with 15 real prameters, the analytical formula involves the sum over four real roots of a quartic equation. The associated cubic resolvent equation with three positive roots belongs again to the irreducible case. Furthermore, by imposing the pertinent condition on $S U (4)$ matrices one can also treat the symplectic group $S p (2)$ with ten real parameters. Since there the roots occur as two pairs of opposite sign, this simplifies the analytical formula for $S p (2)$ matrices considerably. An outlook to the situation with analytical formulas for $S U (5)$ , $S U (6)$ and $S p (3)$ is also given.
Comments:
8 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2207.02167 [pdf]
EPJA(2022)·6 citations

Affiliations

first authorsco-authorsvia INSPIRE

Cluster folding analysis for the 6,7Li and 20Ne + 24Mg nuclear systems

Covariant Density Functional Theory with Localized Exchange Terms

Nuclear incompressibility and sound speed in uniform matter and finite nuclei

Final state interactions in semi-inclusive neutrino-nucleus scattering: Application to T2K and MINERνA experiments

Solving the matrix exponential function for the groups SU(3), SU(4) and Sp(2)

Affiliations

Final state interactions in semi-inclusive neutrino-nucleus scattering: Application to T2K and MINER $ν$ A experiments