Beta Decay as a Test of theSr883−Wave Function

Abstract

Allowed DT =1 Gamow-Teller P decay from the Rb 2 ground state to the Sr 3 level at 2.73 MeV is calculated. A one-particleone-hole description of the latter state requires the [2P~&2 (n)2d5&2(n)]~6 component in order to predict the observed logft value of 6.7. The decay rate is extremely sensitive to the amplitude of this term.One of the main reasons for the considerable recent interest in the mass-88 region is the neutronshell closure at the magic number of 50 (completing the 1g, &, shell). This closure forms a basis for the theoretical studies of Sr" by Hughes, ' Sha, stry and Saha, and Shastry. Hughes a,nd Refs. 2 and 3 differ, however, in their treatment of the 38 protons. It is appealing to treat the 2P», proton shell as closed at 38. This doubly magic picture of the Sr" ground state simplifies calculations and is an additional assumption in Refs. 2 and 3. The 3 level at 2. 73 MeV is especially interesting, as it is strongly collective. This state is built up in Ref. 2 out of 14 proton 1p-1h components, and in Ref. 3 three neutron 1p-1h terms are added. (Reference 1 does not consider negativeparity levels. ) Because of these neutron components there is a substantial improvement in the calculated energy of the 3, state and its B(E3) to the ground state. 3 In the present paper we test the importance of these neutron terms by calculating the allowed nT = 1 Gamow-Teller (GT) P decay to the 3 level from the 2 ground state of Rb".

Gamow-Teller ? transition from the 2? ground state of88Rb to the 3? excited state of88Sr

“…Due to the great interest in evaluating observables in the A=88 system we calculated the G-T NME corresponding to the fitransition mentioned above using available complete wave functions for the initial and final states. Thus, it is the purpose of the present note to complete the estimations performed by Beres and Dorenbusch [7] and to compare the result with a recent experimental value.…”

“…In this way, the authors of [5] and [1][2][3][4][5][6] could explain the collective nature of the 3-octupole state. Some years ago Beres and Dorenbusch [1][2][3][4][5][6][7] have already discussed the G-T/?-decay from the ground state of 88Rb. The authors of [7] have estimated the G-T nuclear matrix element (NME) using the wave functions of the 3 -level of SaSr reported in [5] and [6] and assuming a very simple wave function for the ground state 2-of SSRb due to the lack of more complete information about it.…”

“…Some years ago Beres and Dorenbusch [1][2][3][4][5][6][7] have already discussed the G-T/?-decay from the ground state of 88Rb. The authors of [7] have estimated the G-T nuclear matrix element (NME) using the wave functions of the 3 -level of SaSr reported in [5] and [6] and assuming a very simple wave function for the ground state 2-of SSRb due to the lack of more complete information about it. After the paper by Beres and Dorenbusch [7] a wave function for the ground state of SaRb has been published by Vergados [8].…”

“…In our calculations we used the value C A = -1.250 + 0.009 publishe d recently by Kropf and Paul [11]. It is necessary to point out that (1) in [7] is not correct [cf. with our (1)] and that such an error has been dragged along the whole that paper.…”

“…The authors of [7] have estimated the G-T nuclear matrix element (NME) using the wave functions of the 3 -level of SaSr reported in [5] and [6] and assuming a very simple wave function for the ground state 2-of SSRb due to the lack of more complete information about it. After the paper by Beres and Dorenbusch [7] a wave function for the ground state of SaRb has been published by Vergados [8]. The author of [8] has calculated the wave function including a similar orbital space as Shastry and Saha [5] and Shastry [6].…”