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$^{\rm BSM}_{\rm\ \ BBN}$


  • 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


Monday, June 9

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

Tuesday, June 10

  • 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

Wednesday, June 11

  • 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

Thursday, June 12

  • 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 4He abundance.
group2.txt · Last modified: 2014/06/13 08:49 by bartl