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# Effective theory of a doubly charged singlet scalar: complementarity of neutrino physics and the LHC

King, Stephen F., Merle, Alexander and Panizzi, Luca (2014) Effective theory of a doubly charged singlet scalar: complementarity of neutrino physics and the LHC. Journal of High Energy Physics.

Record type: Article

## Abstract

We consider a rather minimal extension of the Standard Model involving just one extra particle, namely a single $SU(2)_L$ singlet scalar $S^{++}$ and its antiparticle $S^{--}$. We propose a model independent effective operator, which yields an effective coupling of $S^{\pm \pm}$ to pairs of same sign weak gauge bosons, $W^{\pm} W^{\pm}$. We also allow tree-level couplings of $S^{\pm \pm}$ to pairs of same sign right-handed charged leptons $l^{\pm}_Rl'^{\pm}_R$ of the same or different flavour. We calculate explicitly the resulting two-loop diagrams in the effective theory responsible for neutrino mass and mixing. We propose sets of benchmark points for various $S^{\pm \pm}$ masses and couplings which can yield successful neutrino masses and mixing, consistent with limits on charged lepton flavour violation (LFV) and neutrinoless double beta decay. We discuss the prospects for $S^{\pm \pm}$ discovery at the LHC, for these benchmark points, including single and pair production and decay into same sign leptons plus jets and missing energy. The model represents a minimal example of the complementarity between neutrino physics (including LFV) and the LHC, involving just one new particle, the $S^{\pm \pm}$.

Other
pdf - Accepted Manuscript

Published date: 21 November 2014
Additional Information: 57 pages, 14 figures, 10 tables, version accepted for publication in JHEP
Keywords: hep-ph
Organisations: Physics & Astronomy, Theory Group

## Identifiers

Local EPrints ID: 408834
URI: http://eprints.soton.ac.uk/id/eprint/408834
ISSN: 1029-8479
PURE UUID: bc7367a8-dcb5-4159-b625-f0065b8499f4

## Catalogue record

Date deposited: 28 May 2017 04:03

## Contributors

Author: Stephen F. King
Author: Alexander Merle
Author: Luca Panizzi