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

Abstract

Abstract. The energy centroids and integrated strengths of Gamow-Teller transitions in the β+ and electron-capture decay are analyzed for nuclei whose proton number Z and neutron number N are restricted to 44 ≤ Z ≤ 50 and 50 ≤ N ≤ 58. The analysis is based on data measured both with high-resolution γ-ray spectrometry and total γ-ray absorption techniques. The dependence of the considered quantities on the relative neutron excess are established after taking into account the effects due to the Coulomb interaction and mean-field level occupancies. An extrapolation of this dependence to the lightest known tin isotopes is used to estimate the decay characteristics of 100 Sn and 101 Sn. The values extrapolated for the half-lives of 100 Sn and 101 Sn agree with experimental data. Using the extrapolated values together with shell model predictions, the Q values for the electron-capture decay of 100 Sn is evaluated. The quenching factor for β + and the electron-capture decay of the nuclei under consideration here is established to be 0.56(2) with a possible weak dependence on N − Z.

Discrepancy between experimental and theoretical β-decay rates resolved from first principles

“…The quenching factor we obtain from 2BC depends somewhat on the employed Hamiltonian, and is in the range q 2BC = 0.73 − 0.85. This range is consistent with the value q = 0.75(2) from Batist et al [6]. In the present work, we used the spread of results obtained with the selected set of EFT interactions and 2BC as an estimate of the systematic uncertainty.…”

“…Gamow-Teller transitions are a form of β-decay in which the spins of the β-neutrino pair emitted during [5]), systematics ("Batist et al" [6]), and other models [extreme single-particle model (ESPM), shell-model Monte-Carlo (SMMC), large-space shell-model (LSSM), and finite Fermi systems (FFS)] from Ref. [5].…”

Stellar electron capture rates on neutron-rich nuclei and their impact on stellar core collapse

“…5, panels (b,c)): too high (low) EC rates for negative (positive) Q-values. A possible explanation for this deviation could be a residual isospin, I = (N − Z)/A, dependence of ∆E of the centroid of the GT resonance [19][20][21].…”

Improved Value for the Gamow-Teller Strength of the Sn100 Beta Decay

“…The 1σ error bounds were determined at χ 2 ¼ χ 2 min þ 1 ([25], Eqs. [29,30]) and the statistical uncertainty of the χ 2 values was obtained by performing a simulation for a given ϵ 0 30 times with a sample size of N ¼ 10 5 each. As a consistency check, we applied the same procedure to a β spectrum of 98 Cd generated in coincidence with the 1176 keV γ transition which depopulates the lowest 1 þ state in 98 Ag.…”