The muon abundance in the primordial Universe

Abstract

Muon abundance is required for the understanding of several fundamental questions regarding properties of the primordial Universe. In this paper we evaluate the production and decay rates of muons in the cosmic plasma as a function of temperature. This allows us to determine when exactly the muon abundance disappears. When the Universe cools below the temperature $k{T}_{\mathrm{disappear}}\approx 4.135$ MeV the muon decay rate overwhelms production rates and muons vanish quasi-instantaneously from the Universe. Interestingly, we show that at $T_{\mathrm{disappear}}$ the muon number is nearly equal to baryon abundance.

10 pages APPB, 3 figures, Prepared for the 60th anniversary of the Cracow School of Theoretical Physics; v2 in press: typos corrected and computational details improved

References in corpus (9)

• Ab initio calculation of the neutron-proton mass difference
• QED in finite volume and finite size scaling effect on electromagnetic properties of hadrons
• QED Corrections to Hadronic Processes in Lattice QCD
• Leptonic decay constants fK, fD and fDs with Nf = 2+1+1 twisted-mass lattice QCD
• Finite-Volume QED Corrections to Decay Amplitudes in Lattice QCD
• A note on isospin violation in Pl2(gamma) decays
• Relic Neutrino Freeze-out: Dependence on Natural Constants
• Pion and muon production in electron-positron photon plasma
• Comparison of lattice QCD+QED predictions for radiative leptonic decays of light mesons with experimental data