New Physics Effect on Bs, d → l+l− Decays

The rare leptonic decays B s , d → l + l − ( l = e , μ , τ ) present an important base to analyse the flavour structure of the standard model (SM) and also become a potential source to dig out possible signatures of new physics (NP) beyond the SM. The muonic decay B s , d → μ + μ − has been observed at the LHC as well as the upper limits of branching ratios for other B s , d → l + l − decays have been updated recently. In this paper, using the χ 2 fitting method we have studied all these decay channels considering the effect of a Z ′ boson. Our analysing method reproduces the result of the muonic channel of B s meson, hence we have used the same strategy for the other B s , d → l + l − decays.