English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

These proceedings review the differential decay rates and the branchingratios of the tau and muon decays $\tau \to \ell \ell' \ell' \nu \bar\nu$ (with$\ell,\ell'=\mu,e$) and $\mu \to e e e \nu \bar \nu$ in the Standard Model atNLO. These five-body leptonic decays are a tool to study the Lorentz structureof weak interactions and to test lepton flavour universality. They are also asource of SM background to searches for the lepton-flavour-violating decays$\mu \to e e e$ and $\tau \to \ell \ell' \ell'$. Even if the shift in thebranching ratios induced by radiative corrections turns out to be small and oforder 1% --- mainly due to a running effect of the fine structure constant ---locally in the phase space these corrections can reach the 5 - 10% level,depending on the applied cuts. We found for instance that in the phase spaceregion where the neutrino energies are small, and the momenta of the threecharged leptons have a similar signature as in $\mu \to eee$ and $\tau \to \ell\ell'\ell'$, the NLO corrections decrease the leading-order prediction by about10 - 20%.

NLO prediction for the decays $\tau \to \ell \ell'\ell' \nu \bar \nu$ and $\mu \to e e e \nu \bar\nu$