$B\to K^{\ast }\gamma$: Penguins on the Lattice

Abstract

We calculate the leading-order matrix element for the decay $B\to K^{\ast }\gamma$ in the quenched approximation of lattice QCD on a $24^3\times 48$ lattice at $\beta =6.2$, using an O(a)-improved fermion action. Extrapolating the quark masses to their physical values we obtain an on-shell form factor of $T_1(q^2=0)=0.15+12-14$, where the errors quoted are purely statistical. We find $T_1$ is approximately independent of the spectator quark mass and extract $T_1(q^2=0)=0.15+5-4$ if this independence is assumed. We compare this with the same form factor derived (in the Standard Model) from the CLEO experimental branching ratio of $BR(B\to K^{\ast }\gamma )=(4.5\pm 1.5\pm 0.9)\times 10^{-5}$ and find the results to be consistent within statistical errors.

arXiv comment12 pages, LaTeX article with 4 epsf-included postscript figures, (uuencoded compressed tarfile). Minor change in form factor definitions (for posterity), to standardize on convention of Bernard et al

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Cited by in corpus (19)

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• Towards a Model Independent Analysis of Rare $B$ Decays
• Towards a Model-Independent Analysis of Rare $B$ Decays
• Multichannel one-to-two transition amplitudes in a finite volume
• QCD Sum Rule Analysis of the Decays $B\to K{\ell }^{+}{\ell }^{-}$ and $B\to K^{\ast }{\ell }^{+}{\ell }^{-}$
• Form Factors for B -> pi l nu-bar_l and B -> K* gamma Decays on the Lattice
• Long Distance Contributions to Penguin Processes $b\to s\gamma$ and $b\to d\gamma$
• Uncertainties from Long Range Effects in $B \to K^* γ
• An estimate of the B-->K*gamma form factor
• The $B\to K^{\ast }$ form factors on the lattice
• A lattice study of the exclusive $B\to K^{\ast }\gamma$ decay amplitude, using the Clover action at $\beta =6.0$
• Nuclear Reactions from Lattice QCD
• A study on the rare radiative decay $B_c\to D_s^{\ast }\gamma$
• Penguins leaving the pole: bound-state effects in B decaying to K* + photon
• Probing with Penguins: A lattice calculation of the branching ratio for some of the exclusive modes of $b\to s\gamma$
• Weak Matrix Elements on the Lattice --- Circa 1995
• Study on the rare radiative decay $B_c\to D_s^{\ast }\gamma$ in the standard model and multiscale walking technicolor model
• Update on the lattice calculation of $B\to K^{\ast }\gamma$