arXiv subjects
Publications and source records attributed to Patricia Ball.
Using the QCD sum rules approach and the complete leading--logarithmic short--distance coefficients determining the penguin--amplitude, we obtain $B(B\to K^*γ) = (6.8\pm 2.4)\cdot 10^{-5}$ for top--quark masses in the range (150--200) GeV and $|V_{cb}| = 0.035$ for $τ_B = 1.5\,\text{ps}$. The ratio to the inclusive rate is $B(B\to K^*γ)/B(B\to X_sγ) = (20\pm 6)\% $.
We investigate the semileptonic decays of B and D mesons into $π$ and $ρ$ mesons, respectively, by means of QCD sum rules. We find that for the vector formfactors involved the pole dominance hypothesis is valid to good accuracy with pole masses in the expected range. Pole dominance, however, does not apply to the axial formfactors which results in specific predictions for the predominant polarization of the $ρ$ meson and the shape of the lepton spectrum. For the total decay rates we find $Γ(\bar B^0 \to π^+ e^- \barν) = (5.1\pm 1.1)\,|V_{ub}|^2\, 10^{12}\,{\rm s^{-1}}$, $Γ( D^0 \to π^- e^+ ν) = (8.0\pm 1.7)\,|V_{cd}|^2\, 10^{10}\,{\rm s^{-1}}$, $Γ(\bar B^0 \to ρ^+ e^- \barν) = (1.2\pm 0.4\,)\,|V_{ub}|^2\, 10^{13}\,{\rm s^{-1}}$ and $Γ(D^0 \to ρ^- e^+ν) = (2.4\pm 0.7)\,|V_{cd}|^2\, 10^{9}\,{\rm s^{-1}}$.