Study of B ! J/ !K at Belle

Abstract

Motive of this thesis is to search for B ! XK decay mode, where X may be X(3872) and X(3915) and goes to J/ !, using the data sample of 772 × 106 B¯B pair. We performed signal Monte Carlo (MC) study for B ! J/ ! K decay mode and estimated the reconstruction efficiency for B ! X(3872) K to be is about 9±0.1% and for B ! X(3915) K is about 8.6±0.1%. Based on B ! J/ X Inclusive MC study we expect 51±3 and 209 ±12 events for B ! X(3872)K and B ! X(3915)K decay mode and the corresponding branching fraction is 7.02±0.4(stat)×10−6 and 3.02±0.2(stat) ×10−5, respectively. The used data is collected by belle detector at KEK-B asymmetric e+e− collider.