Higher-order NLO radiative corrections to polarized muon decay spectrum

Abstract

Higher-order QED radiative corrections to muon decay spectrum are evaluated within the QED structure function approach in the next-to-leading order logarithmic approximation. New analytical results are given in the $\mathcal{O}\left({\alpha }^3{\ln }^2(m_{\mu }^2/m_e^2)\right)$ order. Earlier results in $\mathcal{O}\left({\alpha }^2{\ln }^1(m_{\mu }^2/m_e^2)\right)$ and $\mathcal{O}\left({\alpha }^3{\ln }^3(m_{\mu }^2/m_e^2)\right)$ orders are partially corrected. Numerical estimates of different contributions are presented.