cern.ch

Measurement of $CP$ observables in $B^0\to D K^{*0}$ with $D\to K^+K^-$

[to restricted-access page]

Abstract

The decay B0 -> D K*0 and the charge conjugate mode are studied using 1.0fb-1 of pp collision data collected by the LHCb experiment at sqrt(s) = 7TeV in 2011. The CP asymmetry between the B0 -> D K*0 and the B0bar -> D K*0bar decay rates, with the neutral D meson in the CP-even final state K+K-, is found to be A_d_KK = -0.45 +- 0.23 +- 0.02, where the first uncertainty is statistical and the second is systematic. In addition, favoured B0 -> D K*0 decays are reconstructed with the D meson in the non-CP eigenstate K+ pi-. The ratio of the B-flavour averaged decay rates in D decays to CP and non-CP eigenstates is measured to be R_d_KK = 1.36 (+0.37) (-0.32) +- 0.07, where the ratio of the branching fractions of D0 -> K- pi+ to D0 -> K+ K- decays is included as multiplicative factor. The CP asymmetries measured with two control channels, the favoured B0 -> DK*0 decay with D -> K+ pi- and the Bs0bar -> D K*0 decay with D K+ K-, are also reported.

Figures and captions

Feynman diagrams for (a) $ B ^0 \rightarrow \overline{ D }{} ^0 K ^{*0} $ and (b) $ B ^0 \rightarrow D ^0 K ^{*0} $.

B2Dbar[..].pdf [195 KiB]
HiDef png [52 KiB]
Thumbnail [8 KiB]
*.C file
B2DbarKstar.pdf
B2DKstar.pdf [194 KiB]
HiDef png [51 KiB]
Thumbnail [8 KiB] *.C file
B2DKstar.pdf

Invariant mass distributions of ({a}) $ D _{[ K ^+ K ^- ]} \overline{ K }{} ^{*0} $, ({b}) $ D _{[ K ^+ K ^- ]} K ^{*0} $, ({c}) $ D _{[ K ^- \pi ^+ ]} \overline{ K }{} ^{*0} $ and ({d}) $ D _{[ K ^+ \pi ^- ]} K ^{*0} $ candidates. The $ D \overline{ K }{} ^{*0} $ distributions correspond to $\overline{ B }{} ^0$ and $ B ^0_ s $ decays whereas the $ D K ^{*0} $ distributions correspond to $ B ^0$ and $\overline{ B }{} ^0_ s $ decays. The fit functions are superimposed; the different $ B $ decays and combinatorial background components are detailed in the legends.

cBmass[..].pdf [25 KiB]
HiDef png [265 KiB]
Thumbnail [68 KiB]
*.C file
cBmass_D02KK_B0bar_foo_5p8freeslope_noPiPi.pdf
cBmass[..].pdf [25 KiB]
HiDef png [281 KiB]
Thumbnail [71 KiB] *.C file
cBmass_D02KK_B0_foo_5p8freeslope_noPiPi.pdf
cBmass[..].pdf [23 KiB]
HiDef png [280 KiB]
Thumbnail [72 KiB] *.C file
cBmass_D02KPi_SameSign_B0bar_foo_5p8freeslope_noPiPi.pdf
cBmass[..].pdf [23 KiB]
HiDef png [287 KiB]
Thumbnail [73 KiB] *.C file
cBmass_D02KPi_SameSign_B0_foo_5p8freeslope_noPiPi.pdf

Animated gif made out of all figures.

PAPER-2012-042.gif
Thumbnail
thumbnail_PAPER-2012-042.gif

Tables and captions

Signal yields with their statistical uncertainties.

Table_1.pdf [66 KiB]
HiDef png [35 KiB]
Thumbnail [5 KiB]
tex code
Table_1.pdf

Summary of the absolute systematic uncertainties on the measured observables.

Table_2.pdf [49 KiB]
HiDef png [95 KiB]
Thumbnail [13 KiB]
tex code
Table_2.pdf

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