20-25 October 2019
PSI
Europe/Zurich timezone

$\tau \to \mu \mu \mu$ at a rate of one out of $10^{14}$ tau decays?

23 Oct 2019, 11:40
20m
WHGA/001 - Auditorium (PSI)

WHGA/001 - Auditorium

PSI

Oral Session

Speaker

Matteo Fael (KIT Karlsruhe)

Description

Recent improvements of the Large Hadron Collider luminosity and the beginning of Belle II experiment will increase the sensitivity to tau lepton-flavour violating modes. In particular, it has been claimed by Pham in hep-ph/9810484 that $BR(\tau \to 3 \mu)$ could be as large as $10^{−14}$ in the Standard Model with massive neutrinos, contradicting earlier predictions for $BR(\mu \to 3e)$. If this were to be true, this limit could be reached experimentally in the near future (with further upgrades).

In this talk, we present a new calculation of these branching ratios in full generality within the Standard Model including massive neutrinos. By making use of the method of regions, we determine the rates as a double expansion in $m_\nu/m_\tau$ and $m_\tau/M_W$. We also report some discrepancies with previous predictions.

Primary author

Matteo Fael (KIT Karlsruhe)

Co-authors

Emilie Passemar (Indiana University/JLab ) Patrick Blackstone (Indiana University)

Presentation Materials