An amplitude analysis of the final state structure in the ${\overline{B}}_s^0\to J/\psi K^{+}{K}^{-}$ decay mode is performed using $1.0{\mathrm{fb}}^{-1}$ 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 $K^{+}{K}^{-}$ mass spectrum as well as a significant nonresonant $S$-wave contribution over the entire $K^{+}{K}^{-}$ mass range. The largest resonant component is the $\varphi (1020)$, accompanied by $f_0(980)$, $f_2^{\prime }(1525)$, and four additional resonances. The overall branching fraction is measured to be $\mathcal{B}({\overline{B}}_s^0\to J/\psi K^{+}{K}^{-})=(7.70\pm 0.08\pm 0.39\pm 0.60)\times {10}^{-4}$, 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 $B^{-}$ mesons produced. The mass and width of the $f_2^{\prime }(1525)$ are measured to be $1522.2\pm {2.8}_{-2.0}^{+5.3}\mathrm{MeV}$ and $84\pm 6_{-5}^{+10}\mathrm{MeV}$, respectively. The final state fractions of the other resonant states are also reported.

• Received 5 February 2013

DOI:https://doi.org/10.1103/PhysRevD.87.072004

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© 2013 CERN, for the LHCb collaboration