No Arabic abstract
The $B^{+}to D^{+} K^{+} pi^{-}$ decay is observed in a data sample corresponding to $3.0,{rm fb}^{-1}$ of $pp$ collision data recorded by the LHCb experiment during 2011 and 2012. The signal significance is $8,sigma$ and the branching fraction is measured to be ${cal B}left(B^{+}to D^{+} K^{+} pi^{-}right) = (5.31 pm 0.90 pm 0.48 pm 0.35)times 10^{-6}$, where the uncertainties are statistical, systematic and due to the normalisation mode $B^{+}to D^{-} K^{+} pi^{+}$, respectively. The Dalitz plot appears to be dominated by broad structures. Angular distributions are exploited to search for quasi-two-body contributions from $B^{+}to D^{*}_{2}(2460)^{0}K^{+}$ and $B^{+}to D^{+} K^{*}(892)^{0}$ decays. No significant signals are observed and upper limits are set on their branching fractions.
The $B^+ to D^{*-}K^+pi^+$ decay potentially provides an excellent way to investigate charm meson spectroscopy. The decay is searched for in a sample of proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of $3~{rm fb}^{-1}$. A clear signal is observed, and the ratio of its branching fraction to that of the $B^+ to D^{*-}pi^+pi^+$ normalisation channel is measured to be begin{equation*} frac{mathcal{B}(B^+ to D^{*-}K^+pi^+)}{mathcal{B}(B^+ to D^{*-}pi^+pi^+)} = left( 6.39 pm 0.27 pm 0.48 right) times 10^{-2} , , end{equation*} where the first uncertainty is statistical and the second is systematic. This is the first observation of the $B^+ to D^{*-}K^+pi^+$ decay.
The $B^{-}to D^{+}K^{-}pi^{-}$ decay is observed in a data sample corresponding to $3.0~rm{fb}^{-1}$ of $pp$ collision data recorded by the LHCb experiment during 2011 and 2012. Its branching fraction is measured to be ${cal B}(B^{-}to D^{+}K^{-}pi^{-}) = (7.31 pm 0.19 pm 0.22 pm 0.39) times 10^{-5}$ where the uncertainties are statistical, systematic and from the branching fraction of the normalisation channel $B^{-}to D^{+}pi^{-}pi^{-}$, respectively. An amplitude analysis of the resonant structure of the $B^{-}to D^{+}K^{-}pi^{-}$ decay is used to measure the contributions from quasi-two-body $B^{-}to D_{0}^{*}(2400)^{0}K^{-}$, $B^{-}to D_{2}^{*}(2460)^{0}K^{-}$, and $B^{-}to D_{J}^{*}(2760)^{0}K^{-}$ decays, as well as from nonresonant sources. The $D_{J}^{*}(2760)^{0}$ resonance is determined to have spin~1.
The first observation of the decay $B^0 rightarrow D^0 overline{D}{}^0 K^+ pi^-$ is reported using proton-proton collision data corresponding to an integrated luminosity of 4.7 $mathrm{fb}^{-1}$ collected by the LHCb experiment in 2011, 2012 and 2016. The measurement is performed in the full kinematically allowed range of the decay outside of the $D^{*-}$ region. The ratio of the branching fraction relative to that of the control channel $B^0 rightarrow D^{*-} D^0 K^+$ is measured to be $mathcal{R} = (14.2 pm 1.1 pm 1.0)%$, where the first uncertainty is statistical and the second is systematic. The absolute branching fraction of $B^0 rightarrow D^0 overline{D}{}^0 K^+ pi^-$ decays is thus determined to be $mathcal{B}(B^0 rightarrow D^0 overline{D}{}^0 K^+ pi^-) = (3.50 pm 0.27 pm 0.26 pm 0.30) times 10^{-4}$, where the third uncertainty is due to the branching fraction of the control channel. This decay mode is expected to provide insights to spectroscopy and the charm-loop contributions in rare semileptonic decays.
First observations of the Cabibbo suppressed decays B0bar -->D+ K- pi+ pi- and B- --> D0 K- pi+ pi- are reported using 35 pb^{-1} of data collected with the LHCb detector. Their branching fractions are measured with respect to the corresponding Cabibbo favored decays, from which we obtain B(B0bar --> D+ K- pi+ pi-)/B(B0bar --> D+ pi- pi+ pi-)=(5.9pm1.1pm0.5) x 10^{-2} and B(B- --> D0 K- pi+ pi-)/B(B- --> D0 pi- pi+ pi-)=(9.4pm1.3pm0.9) x 10^{-2}, where the uncertainties are statistical and systematic, respectively. The B- --> D0 K- pi+ pi- decay is particularly interesting, as it can be used in a similar way to B- --> D0 K- to measure the CKM phase gamma.
We report the first observation of the doubly Cabibbo-suppressed decay $D^+_sto K^+K^+pi^-$ using 605 fb$^{-1}$ of data collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. The branching ratio with respect to its Cabibbo-favored counterpart $mathcal{B}(D^+_sto K^+K^+pi^-)$ / $mathcal{B}(D^+_sto K^+K^-pi^+)$ is (0.229$pm0.028pm$0.012)%, where the first uncertainty is statistical and the second is systematic. We also report a significantly improved measurement of the doubly Cabibbo-suppressed decay $D^+to K^+pi^+pi^-$, with a branching ratio $mathcal{B}(D^+to K^+pi^+pi^-)$ / $mathcal{B}(D^+to K^-pi^+pi^+)$=(0.569$pm0.018pm$0.014)%.