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Register a new userMeasurement of the CKM angle gamma using B^pm --> D K^pm with D-->K_Spi^+pi^-, K_SK^+K^- decays
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A binned Dalitz plot analysis of $B^pm to D K^pm$ decays, with $D to K_S pi^+pi^-$ and $D to K_S K^+ K^-$, is performed to measure the CP-violating observables $x_{pm}$ and $y_{pm}$, which are sensitive to the Cabibbo-Kobayashi-Maskawa angle $gamma$. The analysis exploits a sample of proton-proton collision data corresponding to 3.0invfb collected by the LHCb experiment. Measurements from CLEO-c of the variation of the strong-interaction phase of the $D$ decay over the Dalitz plot are used as inputs. The values of the parameters are found to be $x_+ = (-7.7 pm 2.4 pm 1.0 pm 0.4)times 10^{-2}$, $x_- = (2.5 pm 2.5 pm 1.0 pm 0.5) times 10^{-2}$, $y_+ = (-2.2 pm 2.5 pm 0.4 pm 1.0)times 10^{-2}$, and $y_- = (7.5 pm 2.9 pm 0.5 pm 1.4) times 10^{-2}$. The first, second, and third uncertainties are the statistical, the experimental systematic, and that associated with the precision of the strong-phase parameters. These are the most precise measurements of these observables and correspond to $gamma = (62^{,+15}_{,-14})^circ$, with a second solution at $gamma to gamma + 180^circ$, and $r_B = 0.080^{+ 0.019}_{-0.021}$, where $r_B$ is the ratio between the suppressed and favoured $B$ decay amplitudes.
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A measurement of $CP$-violating observables is performed using the decays $B^pmto D K^pm$ and $B^pmto D pi^pm$, where the $D$ meson is reconstructed in one of the self-conjugate three-body final states $K_{mathrm S}pi^+pi^-$ and $K_{mathrm S}K^+K^-$ (commonly denoted $K_{mathrm S} h^+h^-$). The decays are analysed in bins of the $D$-decay phase space, leading to a measurement that is independent of the modelling of the $D$-decay amplitude. The observables are interpreted in terms of the CKM angle $gamma$. Using a data sample corresponding to an integrated luminosity of $9,text{fb}^{-1}$ collected in proton-proton collisions at centre-of-mass energies of $7$, $8$, and $13,text{TeV}$ with the LHCb experiment, $gamma$ is measured to be $left(68.7^{+5.2}_{-5.1}right)^circ$. The hadronic parameters $r_B^{DK}$, $r_B^{Dpi}$, $delta_B^{DK}$, and $delta_B^{Dpi}$, which are the ratios and strong-phase differences of the suppressed and favoured $B^pm$ decays, are also reported.
A model-dependent amplitude analysis of $B^{pm} rightarrow D K^{pm}$ with $D rightarrow K_S^0 pi^+ pi^-$ decays is performed using proton-proton collision data, corresponding to an integrated luminosity of $1$ fb$^{-1}$, recorded by LHCb at a centre-of-mass energy of $7$ TeV in $2011$. Values of the $CP$ violation observables $x_{pm}$ and $y_{pm}$, which are sensitive to the CKM angle $gamma$, are measured to be begin{align*} x_- &= +0.027 pm 0.044 ^{+0.010}_{-0.008} pm 0.001, y_- &= +0.013 pm 0.048 ^{+0.009}_{-0.007} pm 0.003, x_+ &= -0.084 pm 0.045 pm 0.009 pm 0.005, y_+ &= -0.032 pm 0.048 ^{+0.010}_{-0.009} pm 0.008, end{align*} where the first uncertainty is statistical, the second systematic and the third arises from the uncertainty of the $D rightarrow K_S^0 pi^+ pi^-$ amplitude model. The value of $gamma$ is determined to be $(84^{+49}_{-42})^circ$, including all sources of uncertainty. Neutral $D$ meson mixing is found to have negligible effect.
We present the first model-independent measurement of the CKM unitarity triangle angle $phi_3$ using $B^{pm}to D(K_{rm S}^0pi^+pi^-pi^0)K^{pm}$ decays, where $D$ indicates either a $D^{0}$ or $overline{D}^{0}$ meson. Measurements of the strong-phase difference of the $D to K_{rm S}^0pi^+pi^-pi^0$ amplitude obtained from CLEO-c data are used as input. This analysis is based on the full Belle data set of $772times 10^{6}$ $Boverline{B}$ events collected at the $Upsilon(4S)$ resonance. We obtain $phi_3 = (5.7~^{+10.2}_{-8.8} pm 3.5 pm 5.7)^{circ}$ and the suppressed amplitude ratio $r_{B} = 0.323 pm 0.147 pm 0.023 pm 0.051$. Here the first uncertainty is statistical, the second is the experimental systematic, and the third is due to the precision of the strong-phase parameters measured from CLEO-c data. The 95% confidence interval on $phi_3$ is $(-29.7,~109.5)^{circ}$, which is consistent with the current world average.
Measurements of $CP$ observables in $B^pm rightarrow D^{(*)} K^pm$ and $B^pm rightarrow D^{(*)} pi^pm$ decays are presented, where $D^{(*)}$ indicates a neutral $D$ or $D^*$ meson that is an admixture of $D^{(*)0}$ and $bar{D}^{(*)0}$ states. Decays of the $D^*$ meson to the $Dpi^0$ and $Dgamma$ final states are partially reconstructed without inclusion of the neutral pion or photon, resulting in distinctive shapes in the $B$ candidate invariant mass distribution. Decays of the $D$ meson are fully reconstructed in the $K^pm pi^mp$, $K^+ K^-$ and $pi^+ pi^-$ final states. The analysis uses a sample of charged $B$ mesons produced in $pp$ collisions collected by the LHCb experiment, corresponding to an integrated luminosity of 2.0, 1.0 and 2.0 fb$^{-1}$ taken at centre-of-mass energies of $sqrt{s}$ = 7, 8 and 13 TeV, respectively. The study of $B^{pm} to D^{*} K^{pm}$ and $B^{pm} to D^{*} pi^{pm}$ decays using a partial reconstruction method is the first of its kind, while the measurement of $B^{pm} to D K^{pm}$ and $B^{pm} to D pi^{pm}$ decays is an update of previous LHCb measurements. The $B^{pm} to D K^{pm}$ results are the most precise to date.
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