The quantum numbers of the X(3872) meson are determined to be JPC=1 ++ based on angular correlations in B+→X(3872)K + decays, where X(3872)→π+π-J/ψ and J/ψ→μ+μ-. The data correspond to 1.0 fb-1 of pp collisions collected by the LHCb detector. The only alternative assignment allowed by previous measurements JPC=2-+ is rejected with a confidence level equivalent to more than 8 Gaussian standard deviations using a likelihood-ratio test in the full angular phase space. This result favors exotic explanations of the X(3872) state. © 2013 CERN. Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
Aaij, R., Abellan Beteta, C., Adeva, B., Adinolfi, M., Adrover, C., Affolder, A., … Zvyagin, A. (2013). Determination of the X(3872) meson quantum numbers. Physical Review Letters, 110(22). https://doi.org/10.1103/PhysRevLett.110.222001