Measurement of the X(3872) production cross section via decays to J/ψπ + π − in pp collisions at $ \sqrt{s}=7 $ TeV

Abstract

Measurement of the X(3872) production cross section via decays to J/ψπ + π − in pp collisions at √ s = 7 TeVThe CMS collaboration E-mail: cms-publication-committee-chair@cern.chAbstract: The production of the X(3872) is studied in pp collisions at √ 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.

The hidden-charm pentaquark and tetraquark states

“…[658], Guo, Meissner, Wang, and Yang used the Monte Carlo event generator tools Pythia and Herwig to simulate the production of bottom/charm meson and antimeson pairs at hadron colliders in proton-proton/antiproton collisions, and then derived an order-of-magnitude estimate for the production cross sections of the X(3872) as a DD * molecular state at the LHC and Tevatron experiments. Their results are consistent with the experimental measurement by the CDF [712] and CMS [73] collaborations, which are shown in Table 26 together with the predictions of Refs. [708,707].…”

“…Let's cherish all the expected and embrace all the unexpected. Belle [63], BaBar [84] Belle [75], BaBar [90] Belle [76], BaBar [87] Belle [75], BaBar [86] CDF [67], D0 [68] LHCb [91], CMS [73] LHCb [92] BESIII [93] BaBar [62], CLEO [60], Belle [119] BaBar [123] CLEO [120] BESIII [64], Belle [124] BESIII [159] BESIII [160] BESIII [161] BESIII [93] Belle [172], Belle [177] P c (4380) + * 4380 ± 8 ± 29 [2] 205 ± 18 ± 86 [2] LHCb [2] …”

“…Especially, the production rate of the X(3872) is comparable to that of ψ at hadron colliders [67,708,73], which may also imply a cc core within the X(3872). In Ref.…”

“…[589], Butenschoen, He, and Kniehl studied the inclusive hadroproduction of the χ c1 (2P) within the factorization formalism of nonrelativistic QCD at the next-to-leading order. They tested the hypothesis that the X(3872) is a pure χ c1 (2P) charmonium state using the data from the CDF [67,712], CMS [73], and LHCb [91] collaborations. The authors concluded that NLO NRQCD is inconsistent with the hypothesis X(3872) ≡ χ c1 (2P), because they either obtained an unacceptably high value of χ 2 , a value of |R 2P (0)| incompatible with well-established potential models, or an intolerable violation of the NRQCD velocity rules.…”

Measurement of D-meson production at mid-rapidity in pp collisions at $${\sqrt{s}=7}$$ s = 7 TeV

“…In previous analyses, an alternative method based on the ratio of the FONLL cross sections for feed-down and prompt D mesons was also used in the estimation of the systematic uncertainties. In this analysis it was no longer used, on the basis of the observation that FONLL calculations at LHC energies provide a good description of the production cross sections of B 0 , B + and B 0 s mesons at both central and forward rapidity, while it underestimates prompt charm production [43][44][45][46][47][48]. Hence, the uncertainty due to the B feed-down correction is significantly reduced and more symmetric as compared to our previous publications.…”