Evidence for the decay $B^0\to J/\ddot{I}ˆ\ddot{I}‰$ and measurement of the relative branching fractions of $B_s^0$ meson decays to $J/\ddot{I}ˆ\hat{I}\cdot$ and $J/\ddot{I}ˆ\hat{I}{\cdot }^{{}^{\prime }}$

Abstract

First evidence of the $B^0\to J/\ddot{I}ˆ\ddot{I}‰$ decay is found and the $B_s^0\to J/\ddot{I}ˆ\hat{I}\cdot$ and $B_s^0\to J/\ddot{I}ˆ\hat{I}{\cdot }^{\prime }$ decays are studied using a dataset corresponding to an integrated luminosity of 1.0 ${\mathrm{fb}}^{-1}$ collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}=7$ TeV. The branching fractions of these decays are measured relative to that of the ${\mathrm{B}}^0\to J/\ddot{I}ˆ\ddot{I}{}^0$ decay: $$\frac{Br(B^0\to J/\ddot{I}ˆ\ddot{I}‰)}{Br(B^0\to J/\ddot{I}ˆ\ddot{I}{}^0)}=0.89\pm 0.19(stat{)}_{-0.13}^{+0.07}(syst)$$ $$\frac{Br(B_s^0\to J/\ddot{I}ˆ\hat{I}\cdot )}{Br(B^0\to J/\ddot{I}ˆ\ddot{I}{}^0)}=14.0\pm 1.2(stat{)}_{-1.5}^{+1.1}(syst{)}_{-1.0}^{+1.1}(\frac{f_d}{f_s}),$$ $$\frac{Br(B_s^0\to J/\ddot{I}ˆ\hat{I}{\cdot }^{\prime })}{Br(B^0\to J/\ddot{I}ˆ\ddot{I}{}^0)}=12.7\pm 1.1(stat{)}_{-1.3}^{+0.5}(syst{)}_{-0.9}^{+1.0}(\frac{f_d}{f_s}),$$ where the last uncertainty is due to the knowledge of $f_d/f_s$, the ratio of b-quark hadronization factors that accounts for the different production rate of $B^0$ and $B_s^0$ mesons. The ratio of the branching fractions of $B_s^0\to J/\ddot{I}ˆ\hat{I}{\cdot }^{\prime }$ and $B_s^0\to J/\ddot{I}ˆ\hat{I}\cdot$ decays is measured to be $$\frac{Br(B_s^0\to J/\ddot{I}ˆ\hat{I}{\cdot }^{\prime })}{Br(B_s^0\to J/\ddot{I}ˆ\hat{I}\cdot )}=0.90\pm 0.09(stat{)}_{-0.02}^{+0.06}(syst).$$

23 pages, 7 figures