Observation and Properties of the 𝑋(3872) Decaying to 𝐽/𝜓𝜋+𝜋− in 𝑝 ‾ 𝑝 Collisions at √𝑠=1.96 TeV
V. M. Abazov, H. Castilla-Valdez, E. De La Cruz-Burelo, A. Sánchez-Hernández et al. (D0 Collaboration)
Abstract
We report the observation of the 𝑋(3872) in the 𝐽/𝜓𝜋+𝜋− channel, with 𝐽/𝜓 decaying to 𝜇+𝜇−, in 𝑝‾𝑝 collisions at √𝑠=1.96 TeV. Using approximately 230 pb−1 of data collected with the Run II D0 detector, we observe 522±100 𝑋(3872) candidates. The mass difference between the 𝑋(3872) state and the 𝐽/𝜓 is measured to be 774.9±3.1(stat)±3.0(syst) MeV/𝑐2. We have investigated the production and decay characteristics of the 𝑋(3872) and find them to be similar to those of the 𝜓(2𝑆) state.
DOI: 10.1103/PhysRevLett.93.162002