Tz=−1→0βdecays ofNi54

Abstract

We have studied the f decay of the Tz = -1 , f y2 shell nuclei 54Ni, 50Fe, 46Cr, and 42Ti produced in fragmentation reactions. The proton separation energies in the daughter T. = 0 nuclei are relatively large («4-5 MeV) so studies of the y rays are essential. The experiments were performed at GSI as part of the Stopped-beam campaign with the RISING setup consisting of 15 Euroball Cluster Ge detectors. From the newly obtained high precision /1-decay half-lives, excitation energies, and f branching ratios, we were able to extract Fermi and Gamow-Teller transition strengths in these f) decays. With these improved results it was possible to compare in detail the Gamow-Teller (GT) transition strengths observed in beta decay including a sensitivity limit with the strengths of the Tz = +1 to Tz = 0 transitions derived from high resolution (3He,f) reactions on the mirror target nuclei at RCNP, Osaka. The accumulated B(GT) strength obtained from both experiments looks very similar although the charge exchange reaction provides information on a broader energy range. Using the "merged analysis" one can obtain a full picture of the £(GT) over the full Qp range. Looking at the individual transitions some differences are observed, especially for the weak transitions. Their possible origins are discussed.

High-resolution study of Gamow-Teller transitions in theTi48(He3,t)V48Ganioğlu1, Fujita2, Rubio3 et al. 2016Phys. Rev. CSelf Cite11050View full textAdd to dashboardCite

“…These observations have now been followed by studies of the strengths of GT transitions in ( 3 He, t) reactions on the T z = +1, f 7/2 -shell nuclei 42 Ca, 46 Ti, 50 Cr and 54 Fe at RCNP, Osaka. The results were compared with the GT strengths measured in the beta decays of the equivalent T z = −1 nuclei 42 Ti, 46 Cr, 50 Fe and 54 Ni [16]. The comparison of the B(GT) values obtained for the analogous GT transitions in CE and β decay in the f 7/2 -shell confirms the earlier observations that the proportionality in Eq.…”

High-resolution study of Gamow-Teller excitations in theCa42(He3,t)Fujita1, Fujita2, Adachi3 et al. 2015Phys. Rev. CSelf Cite4291090View full textAdd to dashboardCite

“…(2) has been demonstrated to hold for ∆L = 0 transitions with B(GT) ≥ 0.04 in studies of the mass A = 23, 26, 27, and 34 sd-shell nuclear systems [14][15][16][17][18], and also for the mass A = 46, 50, and 54 f -shell nuclei [19]. The deviations were a few to 10% (note that poorer agreement was also found in some specific cases; see the discussions in Ref.…”

“…However, it can be relatively large for weaker states [18]. Recently, the B(GT) values of analogous T z = ±1 → 0 GT transitions obtained from ( 3 He, t) reactions and β-decays, respectively, were compared up to the excitation energies of ≈ 4.5 MeV for A = 46, 50, and 54 isobers [19]. Note that the β decay is not contaminated by the T τ interaction.…”

“…Recently, two sets of accurate 42 Ti β-decay data became available [19,41] at the fragment separator and trap facilities. Using the β-decay half-life T 1/2 , branching ratio BR, and decay Q value (Q EC value) listed in Table V, the B(GT) value for the transition from the g.s.…”

High-precision QEC -value measurement of the superallowed β+ emitter Mg22 and an ab

“…The current extraction of G V and V ud from the superallowed data uses the shell-model-calculated ISB corrections of Towner and Hardy (TH). This is largely due to arXiv:1708.00536v3 [nucl-ex] 6 Nov 2017 the impressive efforts towards experimental testing [7][8][9] and guidance [10][11][12] that their formalism has been exposed to. However, as the experimental f t values have become increasingly more precise -particularly in the last decade -the model-space truncations [13] and small deficiencies that exist in the TH formalism [14] need to be investigated further.…”