Angular correlations in $B^{+}\to X(3872)K^{+}$ decays, with $X(3872)\to {\rho }^{0}J/\psi$, ${\rho }^0\to {\pi }^{+}{\pi }^{-}$ and $J/\psi \to {\mu }^{+}{\mu }^{-}$, are used to measure orbital angular momentum contributions and to determine the $J^{PC}$ value of the $X(3872)$ meson. The data correspond to an integrated luminosity of $3.0{\mathrm{fb}}^{-1}$ of proton-proton collisions collected with the LHCb detector. This determination, for the first time performed without assuming a value for the orbital angular momentum, confirms the quantum numbers to be $J^{PC}=1^{++}$. The $X(3872)$ is found to decay predominantly through an S wave and an upper limit of 4% at 95% C.L. is set on the D-wave contribution.

• Received 23 April 2015

DOI:https://doi.org/10.1103/PhysRevD.92.011102

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© 2015 CERN, for the LHCb Collaboration