Estudo da Sensibilidade de Observaçao do Decaimento Raro $B_s \to \mu^+ \mu^-$ no Detetor Otimizado LHCb

In this work I present the analysis done to estimate the detection feasibility of the $B_s\rightarrow\mu^+\mu^-$ decay in the LHCb detector. Efficiencies and annual yields for signal and background events are obtained. According to the Standard Model, the number of signal events per year to be produced in LHCb is 700 and $\sim$17 should be selected. A ratio of $B/S\sim$5.7 is expected. The main background is due to inclusive $b \bar b$ events. A detailed study of the components of such background has shown that $b\rightarrow\mu\nu_{\mu}X;~\bar b \rightarrow\mu\nu_{\mu}X$ events should be dominant in this selection. Estimates of the signal significance of 2.2 and 4.4 are expected for periods of data taking equivalent to one and five years respectively. An alternative method is also proposed to estimate the background contribution, and similar results with respect to the usual analysis have been obtained.