The scalar particle discovered at the Large Hadron Collider (LHC) has properties very similar to that of a standard model (SM) Higgs boson. Limited experimental knowledge of its model origin, as of now, however, does not rule out the possibility of accommodating this new particle into a beyond the SM (BSM) framework. A few of these schemes suggest that the observed scalar is just the lightest candidate of an enriched sector with several other heavier states awaiting to be detected. Such models with nonminimal scalar sector also accommodate other neutral and electrically charged (singly, doubly, triply, etc.) component fields as prescribed by the specific model. Depending on the mass and electric charge, these new states can produce potential signatures at colliders as well as in low-energy experiments. The presence of a doubly charged scalar, when accompanied by other neutral or charged scalar(s), can also generate neutrino masses. Adopting the second scenario, e.g., Babu-Zee construction, constraints from neutrino physics have been effaced in this study. Here, we investigate a few phenomenological consequences of a uncolored doubly charged scalar which couples to the charged leptons as well as gauge bosons. Restricting ourselves in the regime of conserved charged-parity ($CP$), we assume only a few nonzero 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 flavor 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.

• Received 10 February 2016

DOI:https://doi.org/10.1103/PhysRevD.93.115004