Gamow-Teller strength in the region ofSn100

Abstract

New calculations are presented for Gamow-Teller beta decay of nuclei near 'Sn. Essentially all of the Sn Gamow-Teller decay strength is predicted to go to a single state at an excitation energy of 1.8 MeV inIn. The first calculations are presented for the decays of neighboring odd-even and odd-odd nuclei which show, in contrast to ' Sn, surprisingly complex and broad Gamow-Teller strength distributions. The results are compared to existing experimental data and the resulting hindrance factors are discussed.PACS number(s): 21.10. Pc, 21.60.Cs, 23.40.Hc, 27.60.+j One of the primary new directions in nuclear spectroscopy is in the experimental study and theoretical understanding of nuclei near the limits of particle stability. The heaviest nucleus with an equal number of protons and neutrons predicted to be stable is Sn, and experiments are being planned and carried out at several laboratories to produce and study the decay of this nucleus [1] and others [2,3] in this mass . "egion. One of the most interesting aspects of these proton-rich nuclei is that most of the giant Gamow-Teller resonance lies within the beta-decay Q-value window. We report here on new calculations which show some of the unusual features which one may expect to see in these decays, the special problems associated with their experimental detection and the important nuclear structure information that will be obtained.Our model space, which is similar to that of a number of other calculations [4 -7], is designed for nuclei with Z~50 and ¹~50and starts from a closed-shell configuration for

Systematics of Gamow-Teller beta decay “Southeast” of 100Sn

“…The former explanation does not seem to be convincing since our fit does not detect any noticeable effects of Z and N pairing. The latter interpretation is in agreement with the theoretical estimate of the loss of β-decay strength due to the limited sensitivity of the HR technique [35]. In any case, we conclude that the values of the summed strengths derived from the HR technique are underestimated.…”

16+Spin-Gap Isomer inCd96

“…Core excitations across the N ¼ Z ¼ 50 gaps and the Gamow-Teller strength, BðGTÞ distributions have been studied via large-scale shell-model calculations using the ðg; d; sÞ model space to compare with the experimental BðGTÞ value obtained from the half-life of the isomer. DOI: 10.1103/PhysRevLett.107.172502 PACS numbers: 21.60.Cs, 23.20.Lv, 23.35.+g, 26.20.Àf The nuclear landscape around the heaviest known bound doubly magic self-conjugate nucleus 100 Sn, which resides far from the valley of stability, exhibits a rich variety of nuclear structure phenomena [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. A feature of great interest in this region is the presence of isomeric states, especially those which may undergo particle decay.…”

Shell model monte carlo methods

“…A detailed comparison with experiment is hampered by the fact that the measurement of the β + -decay can only determine the GT strength below a certain energy threshold, so that the experiment actually provides only upper bounds for the quenching. In the case of 96 Pd and 98 Cd it is expected that the measurements miss less than about 10% of the total GT strength [83,84], while for 94 Ru a significant amount of GT strength is predicted at energies that are not accessible in β + experiments [83,84]. It thus seems that SMMC calculations are in excellent agreement with the observed GT quenching for the nuclei 96 Pd and 98 Cd.…”

“…Despite this reasoning, the observed quenching of the GT strength in the N = 50 isotones close to 100 Sn like 94 Ru, 96 Pd and 98 Cd is surprisingly large [82] Strongly truncated shell model calculations are unable to reproduce the strong quenching, as the configuration mixing in these restricted model spaces was found to be insufficient [83,84]. The agreement between theory and experiment has been improved by renormalization of the GT operator to consider (first-order) corrections to the wave functions [85,86,83,84]. As shell model studies of lighter nuclei clearly stressed the need of a complete 0hω shell model basis, it appears unlikely that first-order corrections are sufficient to recover the full quenching of the GT strength due to configuration mixing.…”