The $CP$ asymmetry in $B^-\to D_s^-D^0$ and $B^-\to D^-D^0$ decays is measured using LHCb data corresponding to an integrated luminosity of 3.0 fb$^{-1}$, collected in $pp$ collisions at centre-of-mass energies of 7 and 8 TeV. The results are $A^{CP}(B^-\to D_s^-D^0)=(-0.4\pm 0.5\pm 0.5)\%$ and $A^{CP}(B^-\to D^-D^0)=( 2.3\pm 2.7\pm 0.4)\%$, where the first uncertainties are statistical and the second systematic. This is the first measurement of $A^{CP}(B^-\to D_s^-D^0)$ and the most precise determination of $A^{CP}(B^-\to D^-D^0)$. Neither result shows evidence of $CP$ violation.
Illustration of (left) tree diagram and (right) loop diagram contributions to the decay $ B ^- \rightarrow D ^- D ^0 $ . Similar diagrams, with the $ d $ replaced by $ s $ , apply to the decay $ B ^- \rightarrow D ^-_ s D ^0 $ . |
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Invariant-mass distribution of $ B ^- \rightarrow D ^-_{( s )} D ^0 $ candidates, separated by charge. The top row plots are $ B ^- \rightarrow D ^-_ s D ^0 $ decays with $ D ^0 \rightarrow K^-\pi^+ $ , the second row with $ D ^0 \rightarrow K^-\pi^+\pi^-\pi^+ $ . The plots in the third row correspond to $ B ^- \rightarrow D ^- D ^0 $ candidates with $ D ^0 \rightarrow K^-\pi^+ $ , the bottom row with $ D ^0 \rightarrow K^-\pi^+\pi^-\pi^+ $ . The left plots are $ B ^- $ candidates, the right plots $ B ^+ $ candidates. The overlaid curves show the fits described in the text. |
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Animated gif made out of all figures. |
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Yields and raw asymmetries for $ B ^- \rightarrow D ^-_{( s )} D ^0 $ decays. |
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Created on 02 May 2024.