| In this thesis, we study the inclusive decay rate of B → Xsgamma. Using the framework of the effective field theory, one can systematically analyze this process at mb scale without knowing the details of the physics happening at high energies. The heavy quark effective theory allows an expansion in powers of Λ QCD/mb. We discuss the scheme dependence in intermediate steps and the scheme independence of the Hamiltonian. We calculate the one-loop short-distance QCD corrections to the non-perturbative contributions. The result is GB →Xsg =G0 &cubl0;1+ 2asmb 3p8-2p 23 1+l1+3l2 2m2b - 1 +asmb 3p 2p2 9- 1454 6l2m2b +Oa2s +O1m3b &cubr0;. |
