First application of Markov chain Monte Carlobased Bayesian data analysis to the Dopplershift attenuation method
Abstract
Motivated primarily by the large uncertainties in the thermonuclear rate of the ^{30}P^{(p , γ) 31}S reaction that limit our understanding of classical novae, we carried out lifetime measurements of ^{31}S excited states using the Doppler Shift Lifetimes (DSL2) facility at the TRIUMF Isotope Separator and Accelerator (ISACII) facility. The ^{31}S excited states were populated by the ^{3}He (3^{2}S^{, α) 31}S reaction. The deexcitation γ rays were detected by a clovertype highpurity germanium detector in coincidence with the α particles detected by a silicon detector telescope. We have applied modern Markov chain Monte Carlobased Bayesian statistical techniques to perform lineshape analyses of Dopplershift attenuation method γray data for the first time. We have determined the lifetimes of the two lowestlying ^{31}S excited states. First experimental upper limits on the lifetimes of four higherlying states have been obtained. The experimental results were compared to shellmodel calculations using five universal sdshell Hamiltonians. Evidence for γ rays originating from the astrophysically important J^{π} = 3 /2^{+}, 260keV ^{30}P^{(p , γ) 31}S resonance with an excitation energy of E_{x} = 6390.2 (7) keV in ^{31}S has also been observed, although strong constraints on the lifetime will require better statistics.
 Publication:

Physics Letters B
 Pub Date:
 April 2023
 DOI:
 10.1016/j.physletb.2023.137801
 arXiv:
 arXiv:2203.10336
 Bibcode:
 2023PhLB..83937801S
 Keywords:

 Lifetimes of <SUP>31</SUP>S states;
 <SUP>30</SUP>P<SUP>(p;
 γ) 31</SUP>S reaction;
 Nova nucleosynthesis;
 Bayesian analysis;
 Markov chain Monte Carlo;
 Nuclear Experiment
 EPrint:
 doi:10.1016/j.physletb.2023.137801