### Speaker

Dr
Paul Moch
(Universität Siegen)

### Description

We perform a comprehensive study of charged lepton flavour violation
in Randall-Sundrum (RS) models in a fully 5D quantum-field-theoretical
framework. We consider the RS model with minimal
field content and a ``custodially protected'' extension as well as
three implementations of the IR-brane localized Higgs field,
including the non-decoupling effect of the KK excitations of a
narrow bulk Higgs. Our calculation provides the first complete result for
the flavour-violating electromagnetic dipole operator in
Randall-Sundrum models.
It contains three contributions with different dependence on the
magnitude of the anarchic 5D Yukawa matrix, which can all be
important in certain parameter regions. We
study the typical range for the branching fractions
of $\mu\to e\gamma$, $\mu \to 3e$, $\mu N \to e N$ as well
as $\tau\to \mu\gamma$, $\tau \to 3\mu$
and the electron electric dipole moment by a numerical scan
in both the minimal and the custodial RS model. The
combination of $\mu\to e\gamma$ and $\mu N \to e N$
currently provides the most stringent constraint on the parameter
space of the model. A typical lower limit on the KK scale $T$ is
around $2 \,{\rm TeV}$ in the minimal model (up to 4~TeV in the
bulk Higgs case with large Yukawa couplings), and around $4 \,{\rm TeV}$
in the custodially protected model,
which corresponds to a mass of about 10~TeV for the first
KK excitations, far beyond the lower limit from the non-observation
of direct production at the LHC.

### Primary authors

Dr
Jürgen Rohrwild
(Rudolf Peierls Centre for Theoretical Physics, University of Oxford)
Prof.
Martin Beneke
(Physik-Department T31 Technische Universität München)
Dr
Paul Moch
(Universität Siegen)