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Observation of $B^0 \to \bar{D}^0 K^+ K^-$ and evidence of $B^0_s \to \bar{D}^0 K^+ K^-$

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Abstract

The first observation of the decay B0 -> D0bar K+ K- is reported from an analysis of 0.62 fb-1 of pp collision data collected with the LHCb detector. Its branching fraction is measured relative to that of the topologically similar decay B0 -> D0bar pi+ pi- to be BR(B0 -> D0bar K+ K-)/BR(B0 -> D0bar pi+ pi-) = 0.056+-0.011+-0.007, where the first uncertainty is statistical and the second is systematic. The significance of the signal is 5.8 sigma. Evidence, with 3.8 sigma significance, for Bs -> D0bar K+ K- decays is also presented, with a relative branching fraction of BR(Bs -> D0bar K+ K-)/BR(B0 -> D0bar K+ K-) = 0.90+-0.27+-0.20.

Figures and captions

Sample decay diagrams that contribute to the $ B ^0 \rightarrow \overline{ D }{} ^0 K ^+ K ^- $ final state via (left) $W$-exchange, (right) rescattering from a colour-suppressed decay.

feynma[..].pdf [14 KiB]
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feynman-dsstK.pdf
feynma[..].pdf [14 KiB]
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feynman-d0a0.pdf

Fits to the $ B ^0_{( s )} $ candidate invariant mass distributions for the (left) $\overline{ D }{} ^0 \pi ^+ \pi ^- $ and (right) $\overline{ D }{} ^0 K ^+ K ^- $ samples. Data points are shown in black, the full fitted PDFs as solid blue lines and the components as detailed in the legends. Yields of the partially reconstructed and peaking backgrounds are all small for the $\overline{ D }{} ^0 K ^+ K ^- $ sample.

Dpipi_[..].pdf [9 KiB]
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Dpipi_PAPER_Fit1.pdf
DKK_PA[..].pdf [11 KiB]
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DKK_PAPER_Fit1.pdf

Dalitz plot distributions for (left) $ B ^0 \rightarrow \overline{ D }{} ^0 \pi ^+ \pi ^- $ and (right) $ B ^0 \rightarrow \overline{ D }{} ^0 K ^+ K ^- $ obtained from the signal weights. Note that these distributions contain contributions from charmless peaking backgrounds.

Dpipi_[..].pdf [7 KiB]
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Dpipi_DP_sig_sqr.pdf
DKK_DP[..].pdf [6 KiB]
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DKK_DP_sig_25bins_sqr.pdf

Animated gif made out of all figures.

PAPER-2012-018.gif
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thumbnail_PAPER-2012-018.gif

Supplementary Material [file]

Supplementary material full pdf

Supple[..].pdf [66 KiB]
Supplementary.pdf
Figsupa.pdf [9 KiB]
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Figsupa.pdf
Figsupb.pdf [10 KiB]
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Figsupb.pdf

Created on 09 December 2018.Citation count from INSPIRE on 18 December 2018.