We report a search for charmless hadronic decays of neutral $B$ mesons to $eta K^{*}(892)^{0}$. The results are based on a 711fb$^{-1}$ data sample that contains $772times 10^6 Boverline{B}$ pairs, collected at the $Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric energy $e^+e^-$ collider. We observe the decay for the first time with a significance of 5.0 standard deviations and obtain its branching fraction ${cal B}[B^0toeta K^{*}(892)^{0}]=[2.6pm0.7{rm (stat)}pm0.2{rm (syst)}]times 10^{-6}$. We also measure the $CP$ violating asymmetry as ${cal A}_{CP}[B^0toeta K^{*}(892)^{0}]=-0.22pm0.29{rm (stat)}pm0.07{rm syst}$.
A search for $B_{(s)}^{0} to K_{S}^{0} K^{*}(892)^{0}$ decays is performed using $pp$ collision data, corresponding to an integrated luminosity of $1.0~text{fb}^{-1}$, collected with the LHCb detector at a centre-of-mass energy of $7~text{TeV}$. The $B_{s}^{0} to K_{S}^{0} K^{*}(892)^{0}$ decay is observed for the first time, with a significance of 7.1 standard deviations. The branching fraction is measured to be begin{equation*} mathcal{B}(B_{s}^{0} to bar{K}^{0} K^{*}(892)^{0}) + mathcal{B}(B_{s}^{0} to K^{0} bar{K}^{*}(892)^{0}) = (16.4 pm 3.4 pm 2.3) times 10^{-6}, end{equation*} where the first uncertainty is statistical and the second is systematic. No evidence is found for the decay $B^{0} to K_{S}^{0} K^{*}(892)^{0}$ and an upper limit is set on the branching fraction, $mathcal{B}(B^{0} to bar{K}^{0} K^{*}(892)^{0}) + mathcal{B}(B^{0} to K^{0} bar{K}^{*}(892)^{0}) < 0.96 times 10^{-6}, $ at $90,% $ confidence level. All results are consistent with Standard Model predictions.
A search for the $B^{0}to K^{+}K^{-}$ decay is performed using $pp$-collision data collected by LHCb. The data set corresponds to integrated luminosities of 1 and 2 fb$^{-1}$ at center-of-mass energies of 7 and 8 TeV, respectively. This decay is observed for the first time, with a significance of more than five standard deviations. The analysis also results in an improved measurement of the branching fraction for the $B_s^0to pi^+pi^-$ decay. The measured branching fractions are $BR(B^0to K^+K^-) = (7.80 pm 1.27 pm 0.81 pm 0.21) times 10^{-8}$ and $BR(B_s^0topi^+pi^-) = (6.91 pm 0.54 pm 0.63 pm 0.19 pm 0.40) times 10^{-7}$. The first uncertainty is statistical, the second is systematic, the third is due to the uncertainty on the $B^0to K^+pi^-$ branching fraction used as a normalization. For the $B_s^0$ mode, the fourth accounts for the uncertainty on the ratio of the probabilities for $b$ quarks to hadronize into $B_s^0$ and $B^0$ mesons.
Based on an $e^{+}e^{-}$ collision data sample corresponding to an integrated luminosity of 2.93 $mathrm{fb}^{-1}$ collected with the BESIII detector at $sqrt{s}=3.773 mathrm{GeV}$, the first amplitude analysis of the singly Cabibbo-suppressed decay $D^{+}to K^+ K_S^0 pi^0$ is performed. From the amplitude analysis, the $K^*(892)^+ K_S^0$ component is found to be dominant with a fraction of $(57.1pm2.6pm4.2)%$, where the first uncertainty is statistical and the second systematic. In combination with the absolute branching fraction $mathcal{B}(D^+to K^+ K_S^0 pi^0)$ measured by BESIII, we obtain $mathcal{B}(D^+to K^*(892)^+ K_S^0)=(8.69pm0.40pm0.64pm0.51)times10^{-3}$, where the third uncertainty is due to the branching fraction $mathcal{B}(D^+to K^+ K_S^0 pi^0)$. The precision of this result is significantly improved compared to the previous measurement.
We present a measurement of angular observables, $P_4$, $P_5$, $P_6$, $P_8$, in the decay $B^0 to K^ast(892)^0 ell^+ ell^-$, where $ell^+ell^-$ is either $e^+e^-$ or $mu^+mu^-$. The analysis is performed on a data sample corresponding to an integrated luminosity of $711~mathrm{fb}^{-1}$ containing $772times 10^{6}$ $Bbar B$ pairs, collected at the $Upsilon(4S)$ resonance with the Belle detector at the asymmetric-energy $e^+e^-$ collider KEKB. Four angular observables, $P_{4,5,6,8}$ are extracted in five bins of the invariant mass squared of the lepton system, $q^2$. We compare our results for $P_{4,5,6,8}$ with Standard Model predictions including the $q^2$ region in which the LHCb collaboration reported the so-called $P_5$ anomaly.
The time-integrated Dalitz plot of the three-body hadronic charmless decay ${{overline{B}}^0 to K_{mathrm{scriptscriptstyle S}}^0 pi^+ pi^-}$ is studied using a $pp$ collision data sample recorded with the LHCb detector, corresponding to an integrated luminosity of $3.0;mathrm{fb}^{-1}$. The decay amplitude is described with an isobar model. Relative contributions of the isobar amplitudes to the ${overline{B}^0 to K_{mathrm{scriptscriptstyle S}}^0 pi^+ pi^-}$ decay branching fraction and CP asymmetries of the flavour-specific amplitudes are measured. The CP asymmetry between the conjugate ${overline{B}^0 to K^{*}(892)^{-}pi^+}$ and ${overline{B}^0 to K^{*}(892)^{+}pi^-}$ decay rates is determined to be $-0.308 pm 0.062$.