Speaker
Description
We perform a model-independent study of $c \to s \mu \nu$ mediated transitions to analyze the new physics effects in the presence of right-handed neutrinos. We have adopted the effective field theory approach and write the low-energy effective Hamiltonian including all possible dimension-six operators. The Wilson coefficients introduced through low energy effective Hamiltonian encode all NP that can enter in $ c \to s$ transition at the dimension-six operator level. These Wilson coefficients are determined through a $\chi^2$ fit by using the Miniut package to available experimental data of leptonic $D_{s}^{+} \to \bar{\mu} \nu$ and semileptonic decays $D^{0} \to K^{-} \bar{\mu} \nu$, $D^{+} \to \bar{K^{0}} \bar{\mu} \nu$ and $D^{0} \to K^{*-} \bar{\mu} \nu$, $D^{+} \to \bar{K^{*0}} \bar{\mu} \nu$, $D_{s}^{+} \to \phi \bar{\mu} \nu$. The differential decay width of $B_{c}^{+} \to B_{s} \bar{\mu} \nu$ is derived to investigate the role of right-handed neutrinos in the search for new physics through the three-body decay process. We also make the predictions of $q^2$ spectra for the mode $B_{c}^{+} \to B_{s} \bar{\mu} \nu$ to inspect the effect of the allowed new physics in $ c \to s$ sector through right-handed neutrinos to motivate the future measurements.
