group2

- Ermal (parameter)
- Jianping (analysis)
- Alex B. (code)

We will explore the impact of non-standard model physics on BBN:

- Varying $\Lambda_{QCD}$
- Neutron magnetic moment
- Variations in gravitational constant

For our results, please refer to our final presentation

- decided on project topic
- started familiarizing with BBN code and researching required inputs

- wrote wrapper script enabling us to vary some of the constants like neutron and proton mass, gravitational constant, Hubble parameter etc.
- ran calculations of BBN dependence on grav. constant; H0 seems to be unused by the code, so varying it does not lead anywhere.
- varying $\Lambda_{QCD}$ and the neutron magnetic moment both incluence the deuteron formation rate $p(n,\gamma)d$. Hence we rewrote this rate with parameters in the
`bigbang.f90`

code and wrote a wrapper script which reads in a table with sets of parameters and calculates the BBN composition - started figuring out how the proton-neutron mass splitting and the deuteron properties depend on our input parameters
- fixed several bugs in the code, continued familiarizing ourselves with Fortran and the BBN code

- produced plots of BBN abundance as function of grav. constant
- tried to calculate and fit the $p(n,\gamma)d$ rate to use as input; partially succeeded

- produced data and plots for BBN abundance as function of $\Lambda_{QCD}$ and $\mu_n$
- also looked at the individual effects of $\Lambda_{QCD}$ on the actual inputs to the BBN calculation (neutron-proton mass splitting, neutron life time, deuteron energy, $p(n,\gamma)d$ rate) and identified the life time effect as the main effect driving the change in the
^{4}He abundance. - created final presentation

group2.txt · Last modified: 2014/06/13 08:49 by bartl

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