Alpha decay of thermally excited nuclei

Abstract

One of the prominent decay modes of heavy nuclei which are produced in astrophysical environments at temperatures of the order of $10^9$ K is the $\alpha$ (${}^4$He) decay. Thermally enhanced $\alpha$ decay rates are evaluated within the standard scheme of a tunneling decay where the $\alpha$ particle tunnels through the potential barrier formed by its interaction with the daughter nucleus. Following the observation that there exist several excited levels with the possibility of an $\alpha$ decay when the daughter nucleus is at a shell closure, we focus in particular on decays producing daughter nuclei with the neutron number, N = 126. Within a statistical approach we find that the half-lives, $t_{1/2}(T)$, for temperatures ranging from $T$ = 0 to 2.4 GK can decrease by 1 - 2 orders of magnitude with the exception of the decay of ${}^{212}$Po which decays to the doubly magic daughter ${}^{208}$Pb, where $t_{1/2}(T)$ decreases by 5 orders of magnitude. The effect of these thermally enhanced $\alpha$ decays on the $r$-process nucleosynthesis can be significant in view of the mass build up at the waiting point nuclei with closed neutron shells.

18 pages, 1 figure

References in corpus (15)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• Multi-messenger Observations of a Binary Neutron Star Merger
• Origin of the heavy elements in binary neutron-star mergers from a gravitational wave event
• The Combined Ultraviolet, Optical, and Near-Infrared Light Curves of the Kilonova Associated with the Binary Neutron Star Merger GW170817: Unified Data Set, Analytic Models, and Physical Implications
• The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/VIRGO GW170817. IV. Detection of Near-infrared Signatures of r-process Nucleosynthesis with Gemini-South
• Kilonovae
• Neutron Star Mergers and Nucleosynthesis of Heavy Elements
• SkyNet: A modular nuclear reaction network library
• Critical view of WKB decay widths
• Databases and tools for nuclear astrophysics applications BRUSsels Nuclear LIBrary (BRUSLIB), Nuclear Astrophysics Compilation of REactions II (NACRE II) and Nuclear NETwork GENerator (NETGEN)
• Bayesian Estimation of Thermonuclear Reaction Rates
• Alpha Clustering from the Quartet Model
• Critical view of nonlocal nuclear potentials in alpha decay
• Signature of the N=126 shell closure in dwell times of alpha-particle tunneling
• Manifestation of deformation and nonlocality in $\alpha$ and cluster decay

Cited by in corpus (1)

• Alpha decay law of excited nuclei and its role in stellar decay rates