High-resolution study of Gamow-Teller transitions with the37Cl(3He,t)

Abstract

Under the assumption of isospin symmetry, T z = ±3/2 → ±1/2 Gamow-Teller (GT) transitions in an isobar quartet with a mass A are analogous, where T z = (1/2)(N − Z) is the z component of the isospin T . We studied the T z = +3/2 → +1/2 GT transitions by the 37 Cl( 3 He, t) 37 Ar reaction at an incoming beam energy of E beam = 140 MeV/nucleon with an energy resolution of E = 30 keV. The distribution of the GT strength was obtained up to an excitation energy (E x ) of 14.2 MeV. This distribution was compared with that of the T z = −2/3 → −1/2 transitions studied in 37 Ca β decay up to E x = 8.6 MeV. Although the overall distributions were similar, details of the fine structure were not necessarily reproduced. The experimental results were compared with a shell-model (SM) calculation using the USD interaction and the effective GT operator that compensates for the effect of limited model space. Although the overall distribution was reproduced by the SM calculation, the fragmentation of states was not reproduced. Neutrino cross sections were derived for the 8 B solar-neutrino source.

High-resolution study of Gamow-Teller transitions in the47Ti(3He,t)Ganioğlu1, Fujita2, Fujita3 et al. 2013Phys. Rev. CSelf Cite

“…In the 41 K( 3 He,t) 41 Ca spectrum, the GT strengths are concentrated in the region between 4 − 6 MeV, while in the 47 Ti( 3 He,t) 47 V spectrum, they are spread out in energy. We note that the T z = −3/2 → −1/2, GT transition strengths, i.e., the GT transition strengths that can be observed in the 47 Mn → 47 Cr, β + decay [55], can be deduced from the accurate measurement of analogous GT transitions in the high resolution study of the ( 3 He, t) reaction, if the isospin symmetry [5,56] of the T z = ±3/2 → ±1/2, analogous GT transitions is assumed.…”

“…In Fig. 8, our 0 • spectrum is compared with the 41 K( 3 He, t) 41 Ca spectrum obtained at 0 • and at the same incoming energy of 140 MeV/nucleon at RCNP [53]. The scales of the ordinates are adjusted so that the states populated with the same B(GT) value have the same height in these two spectra.…”

“…One can see that this value is only 40% of the sum-rule-limit value of 3(N − Z) even if the negative contribution from the GT strengths in the β + direction is ignored. A continuum from quasifree scattering (QFS) [40,41] is expected above the proton separation energy of S p = 5.17 MeV. Since there is no theory for reliably calculating the cross section of the QFS continuum, a background described by a smooth line was subtracted in our analysis, as mentioned above.…”

High-resolution study of Gamow-Teller excitations in theCa42(He3,t)Fujita1, Fujita2, Adachi3 et al. 2015Phys. Rev. CSelf Cite4391090View full textAdd to dashboardCite

“…Above the proton separation energy S p of 4.27 MeV, a continuum caused by quasifree scattering (QFS) can appear [36]. Accordingly, above E x ≈ 5.5 MeV, the continuous counts gradually increase with E x [see Fig.…”

“…2), the ∆L = 0 assignment was given if a state shows the ratio of ratio of 0.8 − 1.2 in all four larger angle cuts (for practical examples, see Refs. [36,38]). …”