The first observation of the decay $B^0_s\rightarrow\chi_{ c1}\phi$ and a study of $B^0\rightarrow\chi_{ c1,2}K^{ *0}$ decays are presented. The analysis is performed using a dataset, corresponding to an integrated luminosity of 1.0 fb$^{ -1}$, collected by the LHCb experiment in pp collisions at a centre-of-mass energy of 7 TeV. The following ratios of branching fractions are measured: \begin{ equation*} \begin{ array}{ lll} \dfrac{ \cal{ B}(B^0_s\rightarrow\chi_{ c1}\phi)}{ \cal{ B}(B^0_s\rightarrow J/\psi\phi)} &=& (18.9 \pm1.8\,(stat)\pm1.3\,(syst)\pm0.8\,(\cal{ B})) \times 10^{ -2}, \nonumber \\ \noalign{ \vskip 3pt} \dfrac{ \cal{ B}(B^0\rightarrow\chi_{ c1}K^{ *0})}{ \cal{ B}(B^0\rightarrow J/\psiK^{ *0})} &=& (19.8 \pm1.1\,(stat)\pm1.2\,(syst)\pm0.9\,(\cal{ B})) \times 10^{ -2}, \nonumber \\ \noalign{ \vskip 3pt} \dfrac{ \cal{ B}(B^0\rightarrow\chi_{ c2}K^{ *0})}{ \cal{ B}(B^0\rightarrow\chi_{ c 1}K^{ *0})} &=& (17.1 \pm5.0\,(stat)\pm1.7\,(syst)\pm1.1\,(\cal{ B})) \times 10^{ -2}, \nonumber \\ \noalign{ \vskip 3pt} \end{ array} \end{ equation*} \noindent where the third uncertainty is due to the limited knowledge of the branching fractions of ${ \chi_{ c}\rightarrow J/\psi \gamma}$ modes.
Categories: hep-ex
