No abstract

Experimentalists have long sought a method that allows them to control the branching ratios of an unstable particle decay and direct some decay to follow one specific desired channel without another. The powerful laser could make this a reality. In this letter and within the framework of the standard electroweak model, we investigate theoretically the laser effect on the branching ratios of different Z-boson decay modes by calculating analytically the Z-boson decay into a fermion-antifermion (Z → f f ) pai in the presence of a circularly polarized electromagnetic field. It is found that, at high intensities, the Z-boson could only decay invisibly into neutrinos, and its decay into any other pair of charged fermions becomes impossible due to the increase in the effective mass that fermions acquire inside the electromagnetic field. The influence of the laser frequency and intensity on the lifetime is also included in order to confirm the surprising result obtained for the pion lifetime in a previous paper (Mouslih 2020 Phys. Rev. D 102 073006).

In the first Born approximation and using an elliptically polarized laser field, the Mott scattering of an electron by a Coulomb potential is investigated using the DiracVolkov states to describe the incident and scattered electrons.

In the framework of the electroweak standard model, we investigated, in the center of mass frame, the Higgs boson production in the presence of an intense laser field via e + e − annihilation (e + e − → ZH). By comparing our results with those obtained by Djouadi (2008 Phys. Rept. 457 1) for laser-free process, we show that the circularly polarized laser field affects significantly the s-channel Higgs boson production. We find that for a given number of exchanged photons, laser field strength and frequency, the total cross section decreases by several orders of magnitude. These effects of laser field on cross section are found to be consistent with what was found for muon pair production via QED process in the presence of a circularly polarized laser field (Müller et al 2006 Phys. Rev. D 74 074017).

In this paper, we have investigated the charged kaons decay at the lowest order in the presence of a circularly polarized laser field. To be more precise, we have examined the leptonic decay of both positive (matter) and negative (antimatter) kaon which weakly decay via the exchange of W boson. Indeed, we have derived the expression of the leptonic decay width, the leptonic branching ratio, the leptonic ratio and the charged kaon lifetime by using the decay matrix approach. In addition, by using numerical computation, we have presented and discussed how the laser field influences these physical quantities. Moreover, we have analyzed the effect of the laser field on the parameter associated to the CPT symmetry. Then, we have concluded that, in the presence of an electromagnetic field and based on this CPT symmetry parameter, it is possible to control the dominance of matter over antimatter or vice-versa by applying an external field to either violate or conserve the CPT symmetry.