2013/02/25 by LHCb collaboration, R. Aaij, C. Abellan Beteta +619 · 1 citation
Physics and Astronomy · #hep-ex
paper · pdf · doi:10.1103/physrevlett.110.222001
published as Phys. Rev. Lett. 110, 222001 (2013) · 10 pages, 4 figures
arxiv created 2013/02/25 · arxiv updated 2013/06/20
The quantum numbers of the X(3872) meson are determined to be JPC = 1++ based on angular correlations in B+ to X(3872) K+ decays, where X(3872) to pi+pi- J/psi and J/psi to 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 eight Gaussian standard deviations using the likelihood-ratio test in the full angular phase space. This result favors exotic explanations of the X(3872) state.