Amplitude analysis and branching fraction measurement ofB¯s0→J/ψK+K−

An amplitude analysis of the final state structure in the ${\overline{B}}_{s}^{0}\ensuremath{\rightarrow}J/\ensuremath{\psi}{K}^{+}{K}^{\ensuremath{-}}$ decay mode is performed using $1.0\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of data collected by the LHCb experiment in 7 TeV center-of-mass energy $pp$ collisions produced by the LHC. A modified Dalitz plot analysis of the final state is performed using both the invariant mass spectra and the decay angular distributions. Resonant structures are observed in the ${K}^{+}{K}^{\ensuremath{-}}$ mass spectrum as well as a significant nonresonant $S$-wave contribution over the entire ${K}^{+}{K}^{\ensuremath{-}}$ mass range. The largest resonant component is the $\ensuremath{\phi}(1020)$, accompanied by ${f}_{0}(980)$, ${f}_{2}^{\ensuremath{'}}(1525)$, and four additional resonances. The overall branching fraction is measured to be $\mathcal{B}({\overline{B}}_{s}^{0}\ensuremath{\rightarrow}J/\ensuremath{\psi}{K}^{+}{K}^{\ensuremath{-}})=(7.70\ifmmode\pm\else\textpm\fi{}0.08\ifmmode\pm\else\textpm\fi{}0.39\ifmmode\pm\else\textpm\fi{}0.60)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$, where the first uncertainty is statistical, the second systematic, and the third due to the ratio of the number of ${\overline{B}}_{s}^{0}$ to ${B}^{\ensuremath{-}}$ mesons produced. The mass and width of the ${f}_{2}^{\ensuremath{'}}(1525)$ are measured to be $1522.2\ifmmode\pm\else\textpm\fi{}{2.8}_{\ensuremath{-}2.0}^{+5.3}\text{ }\text{ }\mathrm{MeV}$ and $84\ifmmode\pm\else\textpm\fi{}{6}_{\ensuremath{-}5}^{+10}\text{ }\text{ }\mathrm{MeV}$, respectively. The final state fractions of the other resonant states are also reported.