Analysis of the Quantum Numbers JPC of the X(3872) Particle (original) (raw)
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Analysis of the quantum numbers JPCJ^{PC}JPC of the X(3872)X(3872)X(3872)
We present an analysis of angular distributions and correlations of the X(3872) particle in the exclusive decay mode X(3872)->J/psi pi+ pi- with J/psi->mu+ mu-. We use 780 pb -1 of data from ppbar collisions at sqrt{s} = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. We derive constraints on spin, parity, and charge conjugation parity of the X(3872) particle by comparing measured angular distributions of the decay products with predictions for different JPC hypotheses. The assignments JPC = 1++ and 2-+ are the only ones consistent with the data.
Experimental constraints on the possible J^PC quantum numbers of the X(3872)
arXiv (Cornell University), 2005
We examine possible J P C quantum number assignments for the X(3872). Angular correlations between final state particles in X(3872) → π + π − J/ψ decays are used to rule out J P C values of 0 ++ and 0 −+. The shape of the π + π − mass distribution near its upper kinematic limit favors S-wave over P-wave as the relative orbital angular momentum between the final-state dipion and J/ψ, which strongly disfavors 1 −+ and 2 −+ assignments. The accumulated evidence strongly favors a J P C = 1 ++ assignment for the X(3872), although the 2 ++ possibility is not ruled out by tests reported here. The analysis is based on a sample of X(3872) mesons produced via the exclusive process B → KX(3872) in a 256 fb −1 data sample collected at the Υ(4S) resonance in the Belle detector at the KEKB collider.
Physical Review Letters, 2004
We report the observation of the X(3872) in the J/ψπ+π- channel, with J/ψ decaying to μ+μ-, in pp¯ collisions at √(s)=1.96 TeV. Using approximately 230 pb-1 of data collected with the RunII 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.
Journal of High Energy Physics, 2013
The production of the X(3872) is studied in pp collisions at $ \sqrt{s}=7 $ TeV, using decays to J/ψπ + π −, where the J/ψ decays to two muons. The data were recorded by the CMS experiment and correspond to an integrated luminosity of 4.8 fb−1. The measurements are performed in a kinematic range in which the X(3872) candidates have a transverse momentum 10 < p T < 50 GeV and rapidity |y| < 1.2. The ratio of the X(3872) and ψ(2S) cross sections times their branching fractions into J/ψπ + π − is measured as a function of p T. In addition, the fraction of X(3872) originating from B decays is determined. From these measurements the prompt X(3872) differential cross section times branching fraction as a function of p T is extracted. The π + π − mass spectrum of the J/ψπ + π − system in the X(3872) decays is also investigated.
Determination of the X(3872) meson quantum numbers
Physical review letters, 2013
The quantum numbers of the X(3872) meson are determined to be J(PC)=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 J(PC)=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.