Tau decay in a circularly polarized laser field

Tau tau(-) is the most massive lepton. Therefore, it has several decay channels. Unlike other leptons, tau can decay into hadronic and leptonic particles. In this article, we have studied the leptonic (tau(-)->nu(tau)l(-)(nu) over bar (l)) and two-body hadronic (tau(-) -> nu(tau)h(-)) decays of tau, where l(-) represents the electron or muon, and h(-) refers to one of the mesons pi(-) or K-, in the presence of a circularly polarized monochromatic laser field. Using the Dirac-Volkov formalism for fermions and that of Klein-Gordon for mesons, we have analytically calculated the expression for the total width of the laser-assisted tau decay at the lowest order. We have examined the variation of the total decay width, the multiphoton absorption and emission process, as well as the branching ratios and lifetime as a function of the parameters that characterize the laser field. The results show that the insertion of the laser field reduces the total decay width, and consequently extends the lifetime due to the quantum Zeno effect. More importantly, we found that the application of a laser field with an appropriate frequency and field strength alters the decay width by enhancing some decay modes and suppressing others.