Laser-assisted production of the light charged Higgs boson from top quark decay in the type-I two Higgs doublet model

Abstract We investigate the impact of a circularly polarized laser field on the top quark decay process into a charged Higgs boson ($t\rightarrow bH^+$) within the type-I two Higgs doublet model. Our study aims to explore how an external electromagnetic field can modify key observables and potentially facilitate the experimental detection of the charged Higgs boson, addressing challenges related to missing energy in collider experiments such as the LHC. Employing the Dirac-Volkov formalism, we model the interaction between charged particles and the laser field and demonstrate that the presence of the laser can notably influence the decay branching ratios under suitable conditions. The analysis reveals that both the intensity and frequency of the laser field play a crucial role in determining the decay width. In particular, for a laser field strength of $3.8\times 10^{14}$ V/cm and a photon energy of $0.117$ eV, the branching ratio of the top quark decaying into a charged Higgs boson with mass in the range $80$–$150$ GeV and a bottom quark reaches $0.97$, surpassing the standard $t\rightarrow bW^+$ channel. These results suggest that strong electromagnetic fields can serve as an effective mechanism to enhance signals of new particles, offering promising avenues for experimental searches beyond the Standard Model.