Nuclear Theory·nucl-th
5 papers—3 primary·2 cross-listed
[Submitted on 10 Oct 2018]
H. Garcilazo🇲🇽 · A. Valcarce🇪🇸
The lattice QCD analyses of the HAL QCD Collaboration predicts a strongly attractive potential in the channel which supports a bound state. In this paper we show that this channel together with the channel give rise to a bound state in the state with maximal spin with a binding energy of 17 MeV.
[Submitted on 10 Oct 2018]
G. Naveya · S. I. A. Philominraj · A. Stephen
In this work study on alpha decay chains emerging from isotopes of Z = 122 superheavy nuclei is carried out with emphasize on nuclear deformations and Langer modification. The interest in this particular superheavy nuclei is due to the recent experimental efforts to synthesize the isotope ^{299}120 in a fusion reaction at the velocity filter SHIP (GSI Darmstadt), which makes synthesis of Z = 122 nuclei to occur in the near future, and in turn will give the experimentalist the chance observe the decays associated with the isotopes of this nuclei. We perform our calculations by choosing the Woods Saxon potential for nuclear interaction, along with Coulomb potential and centrifugal potential within the framework of the WKB method. When the centrifugal term is taken in the total potential and WKB integral is done over 1D radial coordinate, it requires the use of Langer modification wherein (l + 1/2 )^2 replaces l(l +1) for consistency of WKB wave function. Hence we have used this Langer modified centrifugal potential. The orientations of deformed nuclei are important, as it affects the touching distance and also influence the nuclear and Coulomb potential, and thus can alter the values of penetration integral and half-life. The results obtained by our calculations are in agreement with the values obtained from various phenomenological models. This study brings out the unique characteristics of alpha chains associated with each isotope, which will be helpful for the experimentalist to decide the isotope they would like to synthesize and also for their post-synthesis study.
[Submitted on 10 Oct 2018]
Qing Zhao🇨🇳 · Zhongzhou Ren🇨🇳 · Mengjiao Lyu🇯🇵 · Hisashi Horiuchi🇯🇵 · Yoshiko Kanada-En'yo🇯🇵 · Yasuro Funaki🇯🇵 · Gerd Röpke🇩🇪 · Peter Schuck🇫🇷 · Akihiro Tohsaki🇯🇵 · Chang Xu🇨🇳 · Taiichi Yamada🇯🇵 · Bo Zhou🇯🇵
In order to study the nucleon-nucleon pairing effects in clustering nuclei, we formulate a superposed Tohsaki-Horiuchi-Schuck-Roepke (THSR) wave function, which includes both molecular-orbit and pairing configurations explicitly. With this new wave function, we investigate the abnormal deuteron-like pn-pairing effect in 10B with T=0 and S=1 (isoscalar) by comparing with isovector NN pairs (T=1, S=1) in 10Be and 10C. Energies are calculated for the ground states of 10Be, 10B and 10C nuclei, and the 1+ excited state of 10B. These energies are essentially improved comparing with studies using previous version of THSR wave function. Further more, overlaps between the total wave function and the pairing component indicate that the NN pairing effect is more visible in 10B than in 10Be and 10C. By analyzing the energies and the overlaps between wave function components, we observe two different mechanisms enhancing the formation of deuteron-like pairs in 10B. We also discuss the pairing effect by showing average distances between components in each nucleus and density distributions of valance nucleons.
[Submitted on 16 Jun 2016] (cross-list from physics.atom-ph)
Marc Diepold (1) · Beatrice Franke (1 and 2) · Julian J. Krauth (1 and 3) · Aldo Antognini (4 and 5) · Franz Kottmann (4) · Randolf Pohl (3 and 1) ((1) Max Planck Institute of Quantum Optics, 85748 Garching, Germany, (2) TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3, Canada, (3) Johannes Gutenberg-Universität Mainz, QUANTUM, Institut für Physik & Exzellenzcluster PRISMA, 55099 Mainz, (4) Institute for Particle Physics and Astrophysics, ETH Zurich, 8093 Zurich, Switzerland, (5) Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland)
We provide an up to date summary of the theory contributions to the 2S-2P Lamb shift and the fine structure of the 2P state in the muonic helium ion . This summary serves as the basis for the extraction of the alpha particle charge radius from the muonic helium Lamb shift measurements at the Paul Scherrer Institute, Switzerland. Individual theory contributions needed for a charge radius extraction are compared and compiled into a consistent summary. The influence of the alpha particle charge distribution on the elastic two-photon exchange is studied to take into account possible model-dependencies of the energy levels on the electric form factor of the nucleus. We also discuss the theory uncertainty which enters the extraction of the isotope shift from the muonic measurements. The theory uncertainty of the extraction is much smaller than a present discrepancy between previous isotope shift measurements. This work completes our series of theory compilations in light muonic atoms which we have performed already for muonic hydrogen, deuterium, and helium-3 ions.
[Submitted on 10 Oct 2018] (cross-list from astro-ph.SR)
G. Cescutti · R. Hirschi · N. Nishimura · T. Rauscher · J. den Hartogh · A. St. J. Murphy · S. Cristallo
We investigated the impact of uncertainties in neutron-capture and weak reactions (on heavy elements) on the s-process nucleosynthesis in low-mass stars using a Monte-Carlo based approach. We performed extensive nuclear reaction network calculations that include newly evaluated temperature-dependent upper and lower limits for the individual reaction rates. Our sophisticated approach is able to evaluate the reactions that impact more significantly the final abundances. We found that beta-decay rate uncertainties affect typically nuclides near s-process branchings, whereas most of the uncertainty in the final abundances is caused by uncertainties in neutron capture rates, either directly producing or destroying the nuclide of interest. Combined total nuclear uncertainties due to reactions on heavy elements are approximately 50%.
first authorsco-authorsvia INSPIRE