Weak Reaction Rates

Ground State Weak Decay Rates

Stellar weak reaction rates (in s^-1) for beta decay (b-), alpha-decay (ad), and sum of positron decay plus electron capture (b+ec), are tabulated for all species in the reaction network. Ground state weak rates are caclulated from the laboratory decay half-lives, and serve as a lower limit to the weak rate independent of temperature.

For nuclei that exhibit long lived isomeric states, we provide a temperature dependent beta decay (b-) or positron decay plus electron capture (b+ec) rate that assumes the ground state and isomer are in thermal equilibrium. These are tabulated vs. the 14 temperatures listed for the strong and electromagnetic rates.
g.s + 1^st ex. st. b- [ Table T9.le.1.5], [ Table T9.ge.2]
g.s + 1^st ex. st. b+ec [ Table T9.le.1.5], [ Table T9.ge.2]

Temperature and Density Dependent Weak Rates on Nucleons

Stellar weak reaction rates on nucleons are tabulated at 10 values of temperature and 7 values of density for electron capture on protons (rpen, captures/sec/proton), positron capture on neutrons (rnep, captures/sec/neutron), and their associated neutrino loss rates (spen, ergs/sec/proton, and snep, ergs/sec/neutron) given the electron degeneracy parameter (chemical potential excluding the electron's rest mass divided by kt). The rates are from Fuller, Fowler, & Newman 1985 ( ApJ 293, 1).

Temperature and Density Dependent Weak Rates on Nuclei

Stellar weak reaction rates (in reactions per second per nucleus) for beta decay (b-), and the sum of positron decay and electron capture (b+ec) on nuclei are tabulated for select species in the reaction network. They are given in 9 tables, each for a specific temperature. Each table consists of a grid of six density*ye points (1.e+6,1.e+7,1.e+8,1.e+9,1.e+10,1.e+11 g cm^-3) arrayed horizontally. For each nucleus (Z,A) and each density*ye point, the beta decay rate (beta-) OUT OF the nucleus, and the sum of positron decay plus electron capture (beta+ec) INTO the nucleus is listed in two columns, respectively. For T9 greater than 1 and density greater than 1.e+6 g/cc, the temperature and density dependent rates are used over the ground state rates. The rates are from Fuller, Fowler, & Newman 1982 ( ApJ 252, 715 and ApJ Suppl 48, 279).

[Tables for T9 = 1.0, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 7.0, 10.0 ]