The radiative B-> rho gamma, B-> omega gamma decay modes are caused by the FCNC process, so they give us good insight towards probing the standard model in order to search for new physics. In this paper, we compute the branching ratio, direct CP asymmetry, and isospin breaking effects using the perturbative QCD approach within the standard model.
The radiative B -> K* gamma mode is caused by a penguin operator which is a quantum correction. Thus this mode may be useful in the search for physics beyond the standard model. In this paper, we compute the branching ratio, direct CP asymmetry, and isospin breaking effects within the Standard Model in the framework perturbative QCD, and discuss how new physics might show up in this decay.
We present a study of the decays B+ -> rho+ gamma, B0 -> rho0 gamma, and B0 -> omega gamma. The analysis is based on data containing 347 million BBbar events recorded with the BaBar detector at the PEP-II asymmetric B factory. We measure the branching fractions BR(B+ -> rho+ gamma) = (1.10 +0.37/-0.33 +/- 0.09) x 10-6 and BR(B0 -> rho0 gamma) = (0.79 +0.22/-0.20 +/- 0.06) x 10-6, and set a 90% C.L. upper limit BR(B0 -> omega gamma) < 0.78 x 10-6. We also measure the isospin-averaged branching fraction BR(B->rho/omega gamma) = (1.25 +0.25/-0.24 +/- 0.09) x 10-6, from which we determine |Vtd/Vts| = 0.200 +0.021/-0.020 +/- 0.015, where the first uncertainty is experimental and the second is theoretical.
The mixing-induced CP asymmetries in B-> K* gamma -> K_S pi^0 gamma and B-> K* gamma -> K_L pi^0 gamma are expected to be small within the standard model. So they are among the most promising decay modes to test the standard model. In this paper, we compute the mixing-induced CP asymmetries in these decay modes, within the framework of the standard model, using perturbative QCD, and our conclusion is S_{K_S pi^0 gamma}=-S_{K_L pi^0 gamma}=-(3.5pm 1.7)times 10^{-2}.
We present an update on total and partial branching fractions and on CP asymmetries in the semi-inclusive decay B -> Xs l+l-. Further, we summarize our results on branching fractions and CP asymmetries for semi-inclusive and fully-inclusive B -> Xs gamma decays. We present the first result on the CP asymmetry difference of charged and neutral B -> Xs gamma$ decays yielding the first constraint on the ratio of Wilson coefficients Im (C8/C7).
We report measurements of isospin asymmetry $Delta_{0-}$ and difference of direct $CP$ asymmetries $Delta A_{CP}$ between charged and neutral $B to X_s gamma$ decays. This analysis is based on the data sample containing $772 times 10^6 Bbar{B}$ pairs that was collected with the Belle detector at the KEKB energy-asymmetric $e^+ e^-$ collider. Using a sum-of-exclusive technique with invariant $X_s$ mass up to 2.8~GeV/$c^2$, we obtain $Delta_{0-} = bigl[-0.48 pm 1.49 {rm (stat.)} pm 0.97 {rm (syst.)} pm 1.15 {(f_{+-}/f_{00})}bigr]$% and $Delta A_{CP} = bigl[+3.69 pm 2.65 {rm (stat.)} pm 0.76{rm (syst.)}bigr]$%, where the last uncertainty for $Delta_{0-}$ is due to the uncertainty on the production ratio of $B^+B^-$ to $B^0bar{B}^0$ in $Upsilon(4S)$ decays. The measured value of $Delta_{0-}$ is consistent with zero, allowing us to constrain the resolved photon contribution in the $B to X_s gamma$, and improve the branching fraction prediction. The result for $Delta A_{CP}$ is consistent with the prediction of the SM. We also measure the direct $CP$ asymmetries for charged and neutral $B to X_s gamma$ decays. All the measurements are the most precise to date.
Cai-Dian Lu
,M. Matsumori
,A.I. Sanda
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(2005)
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"CP Asymmetry, Branching ratios and Isospin breaking effects in B-> rho gamma and B-> omega gamma decays with the pQCD approach"
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Mika Matsumori
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