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Register a new userA study of $CP$ violation in $B^mp rightarrow Dh^mp$ ($h=K,pi$) with the modes $D rightarrow K^mp pi^pm pi^0$, $D rightarrow pi^+pi^-pi^0$ and $D rightarrow K^+K^-pi^0$
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An analysis of the decays of $B^mp rightarrow D K^mp$ and $B^mp rightarrow D pi^mp $ is presented in which the $D$ meson is reconstructed in the three-body final states $K^mp pi^pm pi^0$, $pi^+ pi^- pi^0$ and $K^+ K^- pi^0$. Using data from LHCb corresponding to an integrated luminosity of 3.0 fb$^{-1}$ of $pp$ collisions, measurements of several $CP$ observables are performed. First observations are obtained of the suppressed ADS decay $B^mp rightarrow [pi^mp K^pm pi^0]_D pi^mp$ and the quasi-GLW decay $B^mp rightarrow [K^+ K^- pi^0]_D pi^mp$. The results are interpreted in the context of the unitarity triangle angle $gamma$ and related parameters.
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Time-integrated $CP$ asymmetries in $D^0$ decays to the final states $K^- K^+$ and $pi^- pi^+$ are measured using proton-proton collisions corresponding to $3mathrm{,fb}^{-1}$ of integrated luminosity collected at centre-of-mass energies of $7mathrm{,Tekern -0.1em V}$ and $8mathrm{,Tekern -0.1em V}$. The $D^0$ mesons are produced in semileptonic $b$-hadron decays, where the charge of the accompanying muon is used to determine the initial flavour of the charm meson. The difference in $CP$ asymmetries between the two final states is measured to be begin{align} Delta A_{CP} = A_{CP}(K^-K^+)-A_{CP}(pi^-pi^+) = (+0.14 pm 0.16mathrm{,(stat)} pm 0.08mathrm{,(syst)})% . onumber end{align} A measurement of $A_{CP}(K^-K^+)$ is obtained assuming negligible $CP$ violation in charm mixing and in Cabibbo-favoured $D$ decays. It is found to be begin{align} A_{CP}(K^-K^+) = (-0.06 pm 0.15mathrm{,(stat)} pm 0.10mathrm{,(syst)}) % , onumber end{align} where the correlation coefficient between $Delta A_{CP}$ and $A_{CP}(K^-K^+)$ is $rho=0.28$. By combining these results, the $CP$ asymmetry in the $D^0rightarrowpi^-pi^+$ channel is $A_{CP}(pi^-pi^+)=(-0.20pm0.19mathrm{,(stat)}pm0.10mathrm{,(syst)})%$.
We present an amplitude analysis of the decay $D^{0} rightarrow K^{-} pi^{+} pi^{+} pi^{-}$ based on a data sample of 2.93 ${mbox{,fb}^{-1}}$ acquired by the BESIII detector at the $psi(3770)$ resonance. With a nearly background free sample of about 16000 events, we investigate the substructure of the decay and determine the relative fractions and the phases among the different intermediate processes. Our amplitude model includes the two-body decays $D^{0} rightarrow bar{K}^{*0}rho^{0}$, $D^{0} rightarrow K^{-}a_{1}^{+}(1260)$ and $D^{0} rightarrow K_{1}^{-}(1270)pi^{+}$, the three-body decays $D^{0} rightarrow bar{K}^{*0}pi^{+}pi^{-}$ and $D^{0} rightarrow K^{-}pi^{+}rho^{0}$, as well as the four-body decay $D^{0} rightarrow K^{-}pi^{+}pi^{+}pi^{-}$. The dominant intermediate process is $D^{0} rightarrow K^{-}a_{1}^{+}(1260)$, accounting for a fit fraction of $54.6%$.
A measurement of the $CP$ asymmetries $S_{f}$ and $S_{bar{f}}$ in $B^0to D^{mp}pi^{pm}$ decays is reported. The decays are reconstructed in a dataset collected with the LHCb experiment in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV and corresponding to an integrated luminosity of $3.0 rm{ fb}^{-1}$. The $CP$ asymmetries are measured to be $S_{f} = 0.058 pm 0.020 (rm{stat}) pm 0.011(rm{syst})$ and $S_{bar{f}} = 0.038pm 0.020 (text{stat})pm 0.007 (text{syst})$. These results are in agreement with, and more precise than, previous determinations. They are used to constrain $|sinleft(2beta+gammaright)|$ and $gamma$ to intervals that are consistent with the current world-average values.
Amplitude models are constructed to describe the resonance structure of ${D^{0}to K^{-}pi^{+}pi^{+}pi^{-}}$ and ${D^{0} to K^{+}pi^{-}pi^{-}pi^{+}}$ decays using $pp$ collision data collected at centre-of-mass energies of 7 and 8 TeV with the LHCb experiment, corresponding to an integrated luminosity of $3.0mathrm{fb}^{-1}$. The largest contributions to both decay amplitudes are found to come from axial resonances, with decay modes $D^{0} to a_1(1260)^{+} K^{-}$ and $D^{0} to K_1(1270/1400)^{+} pi^{-}$ being prominent in ${D^{0}to K^{-}pi^{+}pi^{+}pi^{-}}$ and $D^{0}to K^{+}pi^{-}pi^{-}pi^{+}$, respectively. Precise measurements of the lineshape parameters and couplings of the $a_1(1260)^{+}$, $K_1(1270)^{-}$ and $K(1460)^{-}$ resonances are made, and a quasi model-independent study of the $K(1460)^{-}$ resonance is performed. The coherence factor of the decays is calculated from the amplitude models to be $R_{K3pi} = 0.459pm 0.010,(mathrm{stat}) pm 0.012,(mathrm{syst}) pm 0.020,(mathrm{model})$, which is consistent with direct measurements. These models will be useful in future measurements of the unitary-triangle angle $gamma$ and studies of charm mixing and $C!P$ violation.
A model-dependent amplitude analysis of the decay $B^0rightarrow D(K^0_Spi^+pi^-) K^{*0}$ is performed using proton-proton collision data corresponding to an integrated luminosity of 3.0fb$^{-1}$, recorded at $sqrt{s}=7$ and $8 TeV$ by the LHCb experiment. The CP violation observables $x_{pm}$ and $y_{pm}$, sensitive to the CKM angle $gamma$, are measured to be begin{eqnarray*} x_- &=& -0.15 pm 0.14 pm 0.03 pm 0.01, y_- &=& 0.25 pm 0.15 pm 0.06 pm 0.01, x_+ &=& 0.05 pm 0.24 pm 0.04 pm 0.01, y_+ &=& -0.65^{+0.24}_{-0.23} pm 0.08 pm 0.01, end{eqnarray*} where the first uncertainties are statistical, the second systematic and the third arise from the uncertainty on the $Drightarrow K^0_S pi^+pi^-$ amplitude model. These are the most precise measurements of these observables. They correspond to $gamma=(80^{+21}_{-22})^{circ}$ and $r_{B^0}=0.39pm0.13$, where $r_{B^0}$ is the magnitude of the ratio of the suppressed and favoured $B^0rightarrow D K^+ pi^-$ decay amplitudes, in a $Kpi$ mass region of $pm50 MeV$ around the $K^*(892)^0$ mass and for an absolute value of the cosine of the $K^{*0}$ decay angle larger than $0.4$.
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