论文标题
在标准模型II中的$ n _ {\ rm eff} $的精确计算：在有风味振荡和有限温度的QED的情况下，中微子解耦
Towards a precision calculation of $N_{\rm eff}$ in the Standard Model II: Neutrino decoupling in the presence of flavour oscillations and finite-temperature QED
论文作者
论文摘要
我们在这项工作中介绍了有效数量中微子的标准模型基准值的新计算，$ n _ {\ rm eff}^{\ rm sm} $，可以量化宇宙中性中微子至photon的能量密度。该计算考虑了中微子风味振荡，量子电动力学等离子体中的有限温度效应至$ {\ cal o}（e^3）$，其中$ e $是基本电荷，以及对中微子 - 中微子-Neutrino碰撞整体的全面评估。 We provide furthermore a detailed assessment of the uncertainties in the benchmark $N_{\rm eff}^{\rm SM}$ value, through testing the value's dependence on (i)~optional approximate modelling of the weak collision integrals, (ii)~measurement errors in the physical parameters of the weak sector, and (iii)~numerical convergence, particularly in relation to momentum离散化。我们推荐的新型标准模型基准为$ n _ {\ rm eff}^{\ rm sm} = 3.0440 \ pm 0.0002 $，其中名义不确定性主要归因于数值解决方案过程中发生的错误（$ |Δn__ {太阳能混合角度$ \ sin^2θ_{12} $（$ |δn_ {\ rm eff} | \ sim10^{ - 4} $）中的错误。
We present in this work a new calculation of the standard-model benchmark value for the effective number of neutrinos, $N_{\rm eff}^{\rm SM}$, that quantifies the cosmological neutrino-to-photon energy densities. The calculation takes into account neutrino flavour oscillations, finite-temperature effects in the quantum electrodynamics plasma to ${\cal O}(e^3)$, where $e$ is the elementary electric charge, and a full evaluation of the neutrino--neutrino collision integral. We provide furthermore a detailed assessment of the uncertainties in the benchmark $N_{\rm eff}^{\rm SM}$ value, through testing the value's dependence on (i)~optional approximate modelling of the weak collision integrals, (ii)~measurement errors in the physical parameters of the weak sector, and (iii)~numerical convergence, particularly in relation to momentum discretisation. Our new, recommended standard-model benchmark is $N_{\rm eff}^{\rm SM} = 3.0440 \pm 0.0002$, where the nominal uncertainty is attributed predominantly to errors incurred in the numerical solution procedure ($|δN_{\rm eff}| \sim10^{-4}$), augmented by measurement errors in the solar mixing angle $\sin^2θ_{12}$ ($|δN_{\rm eff}| \sim10^{-4}$).
