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تسجيل مستخدم جديدImproved sensitivity to the CKM phase $gamma$ through binning phase space in $B^- to DK^-$, $D to K^+pi^-pi^-pi^+$ decays
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A binning scheme is proposed for $D^0 to K^+pi^-pi^-pi^+ $ phase space that will improve the sensitivity of a $B^- to DK^-$ analysis to the angle $gamma$ of the Cabibbo-Kobayashi-Maskawa Unitarity Triangle. The scheme makes use of amplitude models recently reported by the LHCb collaboration. Assuming that a four-bin scheme optimised on the models retains a similar sensitivity when applied in data, it is estimated that the statistical uncertainty on $gamma$ from the $B$-meson sample so far collected by the LHCb experiment will be as low as 5 degrees. This will be one of the most precise results available for any single decay mode in a $B^- to D K^-$ measurement. Quantum-correlated $Dbar{D}$ data accumulated by the CLEO-c experiment are analysed to provide first constraints on the coherence factors and average strong-phase differences in the four bins, which are necessary inputs for the measurement. These constraints are compared with the predictions of the model, and consequences for the measurement of $gamma$ are discussed.
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We report a study of the suppressed $B^-to DK^-pi^+pi^-$ and favored $B^-to Dpi^-pi^+pi^-$ decays, where the neutral $D$ meson is detected through its decays to the $K^{mp}pi^{pm}$ and CP-even $K^+K^-$ and $pi^+pi^-$ final states. The measurement is
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The decays $Dto K^-pi^+pi^+pi^-$ and $D to K^-pi^+pi^0$ are studied in a sample of quantum-correlated $Dbar{D}$ pairs produced through the process $e^+e^- to psi(3770) to Dbar{D}$, exploiting a data set collected by the BESIII experiment that corresp
onds to an integrated luminosity of 2.93 fb$^{-1}$. Here $D$ indicates a quantum superposition of a $D^0$ and a $bar{D}^0$ meson. By reconstructing one neutral charm meson in a signal decay, and the other in the same or a different final state, observables are measured that contain information on the coherence factors and average strong-phase differences of each of the signal modes. These parameters are critical inputs in the measurement of the angle $gamma$ of the Unitarity Triangle in $B^- to DK^-$ decays at the LHCb and Belle II experiments. The coherence factors are determined to be $R_{K3pi}=0.52^{+0.12}_{-0.10}$ and $R_{Kpipi^0}=0.78 pm 0.04$, with values for the average strong-phase differences that are $delta_D^{K3pi}=left(167^{+31}_{-19}right)^circ$ and $delta_D^{Kpipi^0}=left(196^{+14}_{-15}right)^circ$, where the uncertainties include both statistical and systematic contributions. The analysis is re-performed in four bins of the phase-space of the $D to K^-pi^+pi^+pi^-$ to yield results that will allow for a more sensitive measurement of $gamma$ with this mode, to which the BESIII inputs will contribute an uncertainty of around 6$^circ$.
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