Year: 2003
Type: article
Abstract: We present a calculation of the ${B}^{0}\mathrm{\text{\ensuremath{-}}}{\overline{B}}^{0}$ mixing matrix element in the framework of QCD sum rules for three-point functions. We compute ${\ensuremath{\alpha}}_{s}$ corrections to a three-point function at the three-loop level in QCD perturbation theory, which allows one to extract the matrix element with next-to-leading order (NLO) accuracy. This calculation is imperative for a consistent evaluation of experimentally measured mixing parameters since the coefficient functions of the effective Hamiltonian for ${B}^{0}\mathrm{\text{\ensuremath{-}}}{\overline{B}}^{0}$ mixing are known at NLO. We find that radiative corrections violate factorization at NLO; this violation is under full control and amounts to 10%. The resulting value of the $B$ parameter is found to be ${B}_{B}({m}_{b})=1+{0.1}_{\mathrm{P}\mathrm{T}}\ensuremath{-}{0.05}_{\mathrm{n}\mathrm{o}\mathrm{n}\mathrm{\text{\ensuremath{-}}}\mathrm{P}\mathrm{T}}$.
Source: Physical Review Letters
Language: Latvian
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W1485801324