Goal
Simulate neutrino interactions changing the composition of a neutrino-driven wind.
Procedure
Calculate reaction rates given electron neutrino energy & flux, and electron anti-neutrino energy and flux
modify XNet to include these reaction rates
Run XNet over a typical neutrino-driven wind trajectory.
Resources
Neutrino cross-sections for n and p (Burrows, Reddy, Thompson 2006)
neutrino-driven wind trajectory (from Raph Hix, or arxiv.org/pdf/astro-ph/9912156.pdf, or arxiv.org/pdf/0908.1871.pdf)
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Adding neutrino rates to XNet
net_preprocess.f90
in the desc_known list, include an entry “nu11” and “au12” for neutrino and antineutrino (no reason for the numbers - arbitrary name)
increase ndesc by 2 (152–>154) to account for additional entries
introduce new case in idesc switch statement (we called it case 153 and 154). set iec to 11 and 12 (matching the names above). Farther down, iwk1(n) is set to iec, where n is the number of the reaction.
common.f90
iweak>0 means include all (including weak) interactions. iweak<0 means ONLY weak interactions
define formula for cross section for both neutrinos and antineutrinos in the switch statement if(iweak>0)
rpf1 is set to inverse partition-function stuff if inverse rate, 1 if forward rate (determined by whether a “v” is in the reaction rate database entry
csect1 = reaction rate = (number flux)*(cross section)
Input Parameters
Extracted input parameters from T. Fischer et al. using GSYS 2.4 (a program to extract data points from graphs) http://www.jcprg.org/gsys
Simulations
Ran simulations using xnet for different $Y_e$ values and different progenitor masses. We tried to see the effect of the presence of neutrinos and anti-neutrinos in the r-process abundance patern.