# Observation of $B^0_s\rightarrow\chi_{c1}\phi$ decay and study of $B^0\rightarrow\chi_{c1,2}K^{*0}$ decays

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## Abstract

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 \\ {} \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 \\ {} \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 \\ {} \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.

## Figures and captions

 Leading-order tree level diagram for the $B ^0 _{( s )}\rightarrow \chi _{ c } X$ decays. [Failure to get the plot] Invariant mass distributions for: (a) $B ^0 \rightarrow \chi _{ c } K ^{*0}$ and (b) $B ^0_ s \rightarrow \chi _{ c 1} \phi$ candidates with $\chi _{ c 1}$ mass constraint; (c) $B ^0 \rightarrow \chi _{ c } K ^{*0}$ and (d) $B ^0_ s \rightarrow \chi _{ c 1} \phi$ candidates with $\chi _{ c 2}$ mass constraint. The total fitted function (thick solid blue), signal for the $\chi _{ c 1}$ and $\chi _{ c 2}$ modes (thin green solid and dotted, respectively) and the combinatorial background (dashed blue) are shown. Fig_2.pdf [173 KiB] HiDef png [337 KiB] Thumbnail [234 KiB] *.C file tex code Background-subtracted invariant mass distributions for: (a) ${ J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} \gamma$ and (b) $K ^+ \pi ^-$ final states from $B ^0 \rightarrow \chi _{ c 1} K ^{*0}$ decays obtained with the $\chi _{ c 1}$ mass constraint applied to the $B ^0 _{( s )}$ candidate invariant mass; (c) ${ J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} \gamma$ and (d) $K ^+ \pi ^-$ final states from $B ^0 \rightarrow \chi _{ c 2} K ^{*0}$ decays obtained with the $\chi _{ c 2}$ mass constraint applied to the $B ^0 _{( s )}$ candidate invariant mass; (e) ${ J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} \gamma$ and (f) $K ^+ K ^-$ final states from $B ^0_ s \rightarrow \chi _{ c 1} \phi$ decays obtained with the $\chi _{ c 1}$ mass constraint applied to the $B ^0 _{( s )}$ candidate invariant mass. The total fitted function (solid) and the non-resonant contribution (dotted) are shown. Fig_3.pdf [227 KiB] HiDef png [419 KiB] Thumbnail [322 KiB] *.C file tex code Invariant mass distributions for (a) $B ^0 \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} K ^{*0}$ and (b) $B ^0_ s \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} \phi$. The total fitted function (thick solid blue), signal (thin solid green), the $B ^0_ s \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} K ^{*0}$ (green dotted) and the combinatorial background (dashed blue) are shown. Fig_4.pdf [128 KiB] HiDef png [143 KiB] Thumbnail [99 KiB] *.C file tex code Background-subtracted invariant mass distributions for (a) $K ^+ \pi ^-$ combinations from $B ^0 \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} K ^{*0}$ decays and (b) $K ^+ K ^-$ combination from $B ^0_ s \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} \phi$ decays. The total fitted function (solid) and the non-resonant contribution (dotted) are shown. Fig_5.pdf [139 KiB] HiDef png [136 KiB] Thumbnail [93 KiB] *.C file tex code Animated gif made out of all figures. PAPER-2013-024.gif Thumbnail

## Tables and captions

 Signal yields for the $B$ decays. Table_1.pdf [51 KiB] HiDef png [131 KiB] Thumbnail [54 KiB] tex code Total efficiencies for all decay modes. Uncertainties are statistical only and reflect the size of the simulation sample. Table_2.pdf [51 KiB] HiDef png [116 KiB] Thumbnail [50 KiB] tex code Relative systematic uncertainties (in $\%$) on the ratio of branching fractions. Table_3.pdf [54 KiB] HiDef png [52 KiB] Thumbnail [24 KiB] tex code

Created on 22 October 2019.