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Register a new userBranching Fraction and CP Asymmetry Measurements in Inclusive B -> Xs l+l- and B -> Xs gamma Decays from BABAR
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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).
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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.
We present results from a search for the flavor-changing neutral current decays $Bto Kell^+ell^-$ and $Bto K^*ell^+ell^-$, where $ell^+ell^-$ is either an $e^+e^-$ or $mu^+mu^-$ pair. The data sample comprises $22.7times 10^6$ $Upsilon(4S)to Bbar B$ decays collected with the BABAR detector at the PEP-II $B$ Factory. We obtain the 90% C.L. upper limits ${mathcal B}(Bto Kell^+ell^-)< 0.50times 10^{-6}$ and ${mathcal B}(Bto K^*ell^+ell^-)<2.9times 10^{-6}$, close to Standard Model predictions for these branching fractions. We have also obtained limits on the lepton-family-violating decays $Bto Ke^{pm}mu^{mp}$ and $Bto K^{*}e^{pm}mu^{mp}$.
We measure the branching fraction and time-dependent $CP$-violating asymmetry for $B^0to J/psipi^0$ decays using a data sample of 711 ${rm fb^{-1}}$ collected on the $Upsilon(4S)$ resonance by the Belle experiment running at the KEKB $e^+e^-$ collider. The branching fraction is measured to be $mathcal{B}(B^0to J/psipi^0) = [1.62,pm 0.11~({rm stat}) pm0.07~({rm syst})]times 10^{-5}$, which is the most precise measurement to date. The measured $CP$ asymmetry parameters are $mathcal{S} = -0.59,pm 0.19~({rm stat}) pm 0.03~({rm syst})$ and $mathcal{A} = -0.15,pm 0.14~({rm stat}),^{+0.04}_{-0.03}~({rm syst})$. The mixing-induced $CP$ asymmetry ($mathcal{S}$) differs from the case of no $CP$ violation by 3.0 standard deviations, and the direct $CP$ asymmetry ($mathcal{A}$) is consistent with zero.
We report a study of the charmless hadronic decay of the charged $B$ meson to the three-body final state $K^+ K^- pi^+$. The results are based on a data sample that contains $772times10^6$ $B bar{B}$ pairs collected at the $Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. The measured inclusive branching fraction and the direct $CP$ asymmetry are $(5.38pm0.40pm0.35)times 10^{-6}$ and $-0.170pm0.073pm0.017$, respectively, where the first uncertainties are statistical and the second are systematic. The $K^{+}K^{-}$ invariant mass distribution of the signal candidates shows an excess in the region below $1.5$ GeV/$c^2$, which is consistent with the previous studies from BaBar and LHCb. In addition, strong evidence of a large direct $CP$ asymmetry is found in the $K^{+}K^{-}$ low-invariant-mass region.
We present preliminary results on two analyses performed by the SLD Collaboration using inclusive B decays: a search for CP violation and a search for the b --> sg transition.
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