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Physics of Atomic Nuclei

, Volume 80, Issue 5, pp 995–999 | Cite as

Exotic quarkonium states in CMS

XIX International Moscow School of Physics (44th ITEPWinter School of Physics) and International School of Physics “QCD and Exotic Hadrons” February 16–23, 2016, Serpukhov, Russia/Elementary Particles and Fields Theory
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Abstract

The studies of the production of the X(3872), either prompt or from B-hadron decays, and of the J/ψϕ mass spectrum in B-hadron decays have been carried out by using pp collisions at \(\sqrt s \) = 7 TeV collected with the CMS detector at the LHC. The cross-section ratio of the X(3872) with respect to the ψ(2S) in the J/ψπ + π decay channel and the fraction of X(3872) coming from B-hadron decays are measured as a function of transverse momentum (p T ), covering unprecedentedly high values of p T . For the first time, the prompt X(3872) cross section times branching fraction is extracted differentially in p T and compared with NRQCD predictions. The dipion invariant-mass spectrum of the J/ψπ + π system in the X(3872) decay is also investigated. A peaking structure in the J/ψϕ mass spectrum near threshold is observed in B ±J/ψϕK ± decays. The data sample, selected on the basis of the dimuon decay mode of the J/ψ, corresponds to an integrated luminosity of 5.2 fb−1. Fitting the structure to an S-wave relativistic Breit–Wigner lineshape above a three-body phase-space nonresonant component gives a signal statistical significance exceeding five standard deviations. The fitted mass and width values are m = 4148.0 ± 2.4(stat.) ± 6.3(syst.) MeV and Γ = 28+15 − 11(stat.) ± 19(syst.) MeV, respectively. Evidence for an additional peaking structure at higher J/ψϕ mass is also reported.

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Copyright information

© Pleiades Publishing, Ltd. 2017

Authors and Affiliations

  1. 1.Dipartimento Interateneo di FisicaUniversità di BariBariItaly
  2. 2.INFN, Sezione di BariBariItaly

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