Reconciling $(g-2)_\mu$ and charged lepton flavour violating processes through a doubly charged scalar

TL;DR

This paper explores how a doubly charged scalar could explain the muon g-2 anomaly, induce charged lepton flavor violation, and produce collider signatures, providing a comprehensive phenomenological analysis.

Contribution

It offers a model-independent analysis of the effects of a doubly charged scalar on muon g-2, CLFV processes, and collider signals, with estimates of Yukawa couplings based on scalar mass.

Findings

Yukawa couplings can account for muon g-2 excess.

Certain Yukawa interactions lead to observable CLFV processes.

Collider signatures include same-sign dilepton events from scalar decay.

Abstract

In this work, we investigate the phenomenological consequences of a doubly charged scalar which may belong to different uncoloured scalar multiplets. This doubly charged scalar couples to the charged leptons as well as gauge bosons, which we parametrize in a model independent way. Restricting ourselves in the regime of conserved charged-parity (CP), we assume only a few non-zero Yukawa couplings ($y_{\mu \ell}$, where $\ell=e,\mu,\tau$) between the doubly charged scalar and the charged leptons. Our choices allow the doubly charged scalar to impinge low-energy processes like anomalous magnetic moment of muon and a few possible charged lepton flavour violating (CLFV) processes. These same Yukawa couplings are also instrumental in producing same-sign dilepton signatures at the LHC. In this article we examine the impact of individual contributions from the diagonal and off-diagonal Yukawa couplings in the light of muon $(g-2)$ excess. Subsequently, we use the derived information to inquire the possible CLFV processes and finally the collider signals from the decay of a doubly charged scalar. Our simplified analyses, depending on the mass of doubly charged scalar, provide a good estimate for the magnitude of the concerned Yukawa couplings. Our findings would appear resourceful to test the phenomenological significance of a doubly charged scalar by using complementary information from muon $(g-2)$, CLFV and the collider experiments.