The first observation of the $B^0_s to D_s^{*mp} K^{pm}$ decay is reported using 3.0$fb^{-1}$ of proton-proton collision data collected by the LHCb experiment. The $D_s^{*mp}$ mesons are reconstructed through the decay chain $D_s^{*mp} to gamma D_s^{mp}(K^{mp}K^{pm}pi^{mp})$. The branching fraction relative to that for $B^0_s to D_s^{*-} pi^{+}$ is measured to be $0.068 pm 0.005 ^{+0.003}_{-0.002}$, where the first uncertainty is statistical and the second is systematic. Using a recent measurement of $BR(B^0_s to D_s^{*-} pi^{+})$ the absolute branching fraction of $B^0_s to D_s^{*mp} K^{pm}$ is measured as ( 16.3 $pm$ 1.2 (stat) $^{+0.7}_{-0.5}$ (syst) $pm$ 4.8 (norm) ) $times$ 10$^{-5}$, where the third uncertainty is due to the uncertainty on the branching fraction of the normalisation channel.
The CKM angle $gamma$ is measured for the first time from mixing-induced $CP$ violation between $B^0_s rightarrow D_s^mp K^pm pi^pm pi^mp$ and $bar{B}^0_s rightarrow D_s^pm K^mp pi^mp pi^pm$ decays reconstructed in proton-proton collision data corresponding to an integrated luminosity of 9 ${rm fb}^{-1}$ recorded with the LHCb detector. A time-dependent amplitude analysis is performed to extract the $CP$-violating weak phase $gamma-2beta_s$ and, subsequently, $gamma$ by taking the $B^0_s$-$bar{B}^0_s$ mixing phase $beta_{s}$ as an external input. The measurement yields $gamma = (44 pm 12)^circ$ modulo $180^circ$, where statistical and systematic uncertainties are combined. An alternative model-independent measurement, integrating over the five-dimensional phase space of the decay, yields $gamma = (44^{,+,20}_{,-,13})^circ$ modulo $180^circ$. Moreover, the $B^0_s$-$bar{B}^0_s$ oscillation frequency is measured from the flavour-specific control channel $B^0_s rightarrow D_s^- pi^+ pi^+ pi^-$ to be $Delta m_s = (17.757 pm 0.007 ,({rm stat.}) pm 0.008 ,({rm syst.})) text{ps}^{-1}$, consistent with and more precise than the current world-average value.
We report a measurement of the branching fraction and final-state asymmetry for the $bar{B}^{0}to K^{0}_{S}K^{mp}pi^{pm}$ decays. The analysis is based on a data sample of 711 $rm{fb}^{-1}$ collected at the $Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}e^{-}$ collider. We obtain a branching fraction of $(3.60pm0.33pm0.15)times10^{-6}$ and a final-state asymmetry of $(-8.5pm8.9pm0.2)%$, where the first uncertainties are statistical and the second are systematic. Hints of peaking structures are seen in the differential branching fractions measured as functions of Dalitz variables.
We report a study of the decay $D^0 to K^0_S K^0_S$ using 921~fb$^{-1}$ of data collected at or near the $Upsilon(4S)$ and $Upsilon(5S)$ resonances with the Belle detector at the KEKB asymmetric energy $e^+e^-$ collider. The measured time-integrated $CP$ asymmetry is $ A_{CP}(D^0 to K^0_S K^0_S) = (-0.02 pm 1.53 pm 0.02 pm 0.17) %$, and the branching fraction is $mathcal{B} (D^{0}rightarrow K_{S}^{0}K_{S}^{0})$ = (1.321 $pm$ 0.023 $pm$ 0.036 $pm$ 0.044) $times$ 10$^{-4}$, where the first uncertainty is statistical, the second is systematic, and the third is due to the normalization mode ($D^0 to K_S^0 pi^0$). These results are significantly more precise than previous measurements available for this mode. The $A_{CP}$ measurement is consistent with the standard model expectation.
We present the first search for the rare decay of $eta^prime$ into $K^{pm}pi^{mp}$ in $J/psitophieta^{prime}$, using a sample of $1.3times10^{9}$ $J/psi$ events collected with the BESIII detector. No significant signal is observed, and the upper limit at the 90% confidence level for the ratio $frac{{cal B}(eta^{prime}to K^{pm}pi^{mp})}{{cal B}(eta^{prime}togammapi^{+}pi^{-})}$ is determined to be $1.3times10^{-4}$. In addition, we report the measurement of the branching fraction of $J/psitophieta^{prime}$ to be $(5.10pm0.03(text{stat.})pm0.32(text{syst.}))times10^{-4}$, which agrees with previous results from BESII.
We report a measurement of the $B^0$ and $B^+$ meson decays to the $D_s^-K^0_S pi^+$ and $D_s^- K^+K^+$ final states, respectively, using $657 times 10^{6} Boverline{B}$ pairs collected at the $Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. Using the $D_s^-to phipi^-$, $K^{*}(892)^0 K^-$ and $K^0_S K^-$ decay modes for the $D_s$ reconstruction, we measure the following branching fractions: ${cal B}(B^0to D_s^{-}K^0_Spi^+)=[0.47 pm 0.06 (mathrm {stat}) pm 0.05 (mathrm {syst})]times 10^{-4}$ and ${cal B}(B^+to D_s^-K^+K^+)= [0.93 pm 0.22 (mathrm {stat})pm 0.10 (mathrm {syst})]times 10^{-5}$. We find the ratio of the branching fraction of $B^+to D_s^-K^+K^+$ to that of the analogous Cabibbo favored $B^+to D_s^-K^+pi^+$ decay to be ${cal R}_{cal B} = 0.054 pm 0.013 ({rm stat}) pm 0.006 ({rm syst})$, which is consistent with the na{i}ve factorization model. We also observe a deviation from the three-body phase-space model for both studied decays.
LHCb Collaboration: R. Aaij
,B. Adeva
,M. Adinolfi
.
(2015)
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"First observation and measurement of the branching fraction for the decay $B^0_s to D_s^{*mp} K^{pm}$"
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Alessandro Bertolin
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