Isospin mixing in37K and spin decomposition of Gamow-Teller strength in37Ca decay

Abstract

We measured 36 Ar(p ជ ,p 0 ) cross sections and analyzing powers for E p between 3.22 and 5.98 MeV, and used these data to deduce spin, parity, and widths of 17 levels in 37 K. Our results, combined with existing information on 37 Ca ␤ ϩ decay, yield information on the distribution of Fermi and Gamow-Teller strength in this decay. A Tϭ1/2 level lying 31 keV below the J ϭ3/2 ϩ , Tϭ3/2 analog of the 37 Ca ground state was found to have J ϭ3/2 ϩ . The relative proton widths of the two levels imply an isospin-mixing matrix-element of 4.84Ϯ0.43 keV. This agrees with the value 5.93 Ϫ0.65 ϩ0.23 keV extracted from the ␤ ϩ -decay intensities to the two levels, plus the Gamow-Teller to Fermi strength ratio for the 5018 keV level. We decompose the Gamow-Teller strength in 37 Ca decay into components feeding daughter levels with J ϭ1/2 ϩ , 3/2 ϩ , or 5/2 ϩ , and compare the results to theory. None of the available shell-model calculations gives a satisfactory account of the data. ͓S0556-2813͑97͒00602-X͔

Discovery of34g,mCl(p,γ)35Arresonances activated at classical nova temperatures

“…The currents are consistent with the solar isotopic abundances for argon, yielding no evidence for beam contaminants that would lead to target contamination. Similar results have been found by other groups [27].…”

“…Additionally, 28 Si(d, t) 27 Si peaks (E x ≈ 4.2-4.5 MeV) were used at 20°and 25°. A quadratic least squares fit was used to calibrate momentum vs. position centroid.…”

High-resolution study of Gamow-Teller transitions with the37Cl(3He,t)Shimbara1, Fujita2, Adachi3 et al. 2012Phys. Rev. C152150View full textAdd to dashboardCite

“…The studies of 36 Ca(p, γ ) 37 K [17] and 40 Ca(p, α) 40 K [18] reactions suggested that a few protonunbound states in 37 K above the proton separation energy had significant probabilities of undergoing γ decay. Actually recalculation of the B(GT) distribution by taking both the delayed proton emission and the γ decay into account reduced a large part of the difference [19,20].…”

Revalidation of the Isobaric Multiplet Mass Equation

“…[24][25][26] as described in Ref. [27]. In order to disentangle the different contributions to the energy resolution in our excitation functions we took data with two different Ag 2 S targets: one 9.3 times thinner than the other one (as measured by the yields in a given detector).…”