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A 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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Abstract

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.

Figures and captions

Invariant mass distributions of selected \favBToDHWithDToKPiPi0 candidates, separated by $ B $ hadron charge. $ B ^\mp \!\rightarrow D K ^\mp $ signal events are in the upper plots and \BToDPi events are in the lower plots. The solid dark (red) curve represents $ B ^\mp \!\rightarrow D K ^\mp $ events and the solid light (green) curve represents \BToDPi events. The solid (grey) shape indicates partially reconstructed $ B ^\mp$ decays and the heavy dotted (red) curve indicates wrongly reconstructed $ D $ decays. The solid (blue) line represents the total PDF and includes the combinatorial component.

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canvas_d2kpipi0.pdf

Invariant mass distributions of selected \supBToDHWithDToKPiPi0 candidates. See the caption of Fig. 1 for a full description. The lightly dotted (blue) line represents the combinatorial component and the long-dashed (magenta) line indicates contributions from partially reconstructed $ B ^0_ s \rightarrow D K ^\mp \pi ^\pm $ decays where the pion is not reconstructed.

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canvas_d2pikpi0.pdf

Invariant mass distributions of selected \BToDHWithDToPiPiPi0 candidates. See the caption of Fig. 1 for a full description. The lightly dotted (blue) line represents the combinatorial component.

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canvas_d2pipipi0.pdf

Invariant mass distributions of selected \BToDHWithDToKKPi0 candidates. See the caption of Fig. 1 for a full description. The lightly dotted (blue) line represents the combinatorial component.

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canvas_d2kkpi0.pdf

Scan of the $\chi^2$ probabilities over the $\gamma $ --$r_B$ parameter space. Shown are the $n\sigma$ profile likelihood contours, where $\Delta\chi^2 = n^2$, with $n=1$ being the light (blue) shaded region, $n=2$ the dark (blue) shaded region and $n=3$ corresponding to the white area. The result is seen to be compatible with the current LHCb measurement of $\gamma $ and $r_B$, indicated by the point with error bars.

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rB_vs_gamma.pdf

Scan of the $\chi^2$ probabilities over the $\gamma $ --$\delta_B$ parameter space. Shown are the $n\sigma$ profile likelihood contours, where $\Delta\chi^2 = n^2$, with $n=1$ being the light (blue) shaded region, $n=2$ the dark (blue) shaded region and $n=3$ corresponding to the white area. The result is compatible with the current LHCb measurement of $\gamma $ and $\delta_B$, indicated by the point with error bars.

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deltaB_vs_gamma.pdf

Animated gif made out of all figures.

PAPER-2015-014.gif
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thumbnail_PAPER-2015-014.gif

Tables and captions

The final signal yields, split in categories based on the charges of the $ B $ hadron (only statistical uncertainties are shown).

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Table_1.pdf

Systematic uncertainties on the observables, multiplied by a factor of $10^{3}$. `PID' refers to the fixed PID efficiency attributed to the bachelor tracks. `PDFs' refers to the uncertainties based on fixed parameters in the PDF shapes that are used in the invariant mass fit. `Sim' refers to the use of simulation to calculate relative efficiencies between the $ B ^\mp \!\rightarrow D K ^\mp $ and \BToDPi modes, in addition to the estimated charmless background contributions and the fixed $DK$ to $D\pi$ ratio on the ADS modes. `$A_{\rm instr}$' refers to the interaction and detection asymmetries. The `Total' column represents the sum in quadrature of all of the categories of systematic uncertainties.

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Supplementary Material [file]

Supplementary material full pdf

supple[..].pdf [221 KiB]
supplementary.pdf

This ZIP file contains supplementary material for the publication LHCb-PAPER-2015-014. The files are: supplementary.pdf : An overview of the extra figures *.pdf, *.png, *.eps, *.C : The figures in various formats

FigS1.pdf [30 KiB]
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FigS1.pdf
FigS2.pdf [30 KiB]
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FigS2.pdf

Created on 09 December 2018.Citation count from INSPIRE on 09 December 2018.