Speaker
Description
The dynamics of neutrinos and antineutrinos within a QED plasma, around MeV temperatures (just prior to their decoupling), influences several key cosmological observables. Precision studies have become timely, and we recently computed the NLO interaction rate as a function of the neutrino momentum and flavour, finding relative corrections on the few percent level [1]. I will summarise this calculation, and explain how the same object can be obtained from an integral of more differential rates describing production, annihilation, and scattering [2]. The latter "double-differential" rates can be used to obtain other quantities, like the energy transfer rates which are needed to estimate the parameter $N_{\rm eff}$ in the Standard Model. To conclude, I will comment on how such rate coefficients serve as input for non-equilibrium neutrino kinetic equations.
[1] G. Jackson, M. Laine, JHEP 05 (2024), 089 [arXiv:2312.07015]
[2] G. Jackson, M. Laine [arXiv:2412.03958]
