  Recently LHCb has measured the branching ratio of the rare decay of
$B_s^0\rightarrow \mu^+ \mu^- $ as $2.9^{+1.1}_{-1.0} \times10^{-9}$ which is
at par with the predicted standard model (SM) value. This result does not
predict the absence of new physics (NP), rather it confines the NP
parameter-space in a more stringent fashion. In this paper we have used the
general loop level Hamiltonian to constrain the parameter space for the NP
couplings for $B_s^0\rightarrow \mu^+ \mu^- $ from the experimental branching
ratio. Using the available parameter space for these couplings, we have
explored the angular analysis of the cascade decay of $B^0_{s}\to \tau^+\tau^-
\to (\rho^+\bar{\nu}_\tau)_{\tau^+}(\pi^{-}\nu_{\tau})_{\tau^-} \to ((\pi^+
\pi^0)_{\rho^+}\bar{\nu}_\tau)_{\tau^+}(\pi^{-}\nu_{\tau})_{\tau^-}$. This
analysis shows presence of NP can be identified by the angular analysis and
also shows how to isolate the NP contribution from the SM. We believe that in
future with the reduced error in the branching ratio measurement and better
$\tau$ cone reconstruction technique we will be able to probe NP signal using
this angular analysis.
