Jim Kneller

North Carolina State University

The effects upon big-bang nucleosynthesis of variations in ΛQCD

Big Bang Nucleosynthesis (BBN) has increasingly become the tool of choice for investigating the permitted variation of fundamental constants during the earliest epochs of the Universe. Here we present a BBN calculation that has been modified to permit changes in the QCD scale, ΛQCD.

The primary effects of changing the QCD scale upon BBN are through the deuteron binding energy, BD, and the neutron-proton mass difference, Δmnp, which both play crucial roles in determining the primordial abundances. Our simplified BBN calculation allows us to restrict any variation in ΛQCD via the corresponding shifts in BD and Δmnp and we show how increased understanding of the relationship of the pion mass and/or BD to other nuclear parameters, such as the binding energy of tritium and the cross section of T+D → 4He+n, yields constraints upon any change in BD and Δmnp at the 10% level.

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