Measurement of the branching fraction of the semileptonic decay neutral anti-B meson decaying to positive D resonance negative muon antinutrino mu in the BABAR experiment

This thesis presents a measurement of the branching fraction for the exclusive semilep-tonic decay ( B&d1;0→D*+ m-n&d1; m ). This decay is essentially the decay of a b quark to a c quark inside the meson with the release of a muon and neutrino, and it provides a very clean signal for measuring various B meson decay properties. The data for this measurement consist of 22.3 million BB¯ pairs collected by the BABAR detector at the Stanford Linear Accelerator Center in 1999--2000. The branching fraction is measured to be BB&d1;0 →D*+m-n&d1; m = [4.72 +/- 0.10 (data stat.) +/- 0.06 (MC stat.) +/- 0.20 (syst.) +/- 0.17 (other B )] %.