Measurement of the relative rate of prompt χ c0, χ c1 and χ c2 production at $ \sqrt{s}=7 $ TeV

Abstract

Measurement of the relative rate of prompt χ c0 , χ c1 and χ c2 production at √ s = 7 TeVThe LHCb collaboration E-mail: tournefier@lapp.in2p3.frAbstract: Prompt production of charmonium χ c0 , χ c1 and χ c2 mesons is studied using proton-proton collisions at the LHC at a centre-of-mass energy of √ s = 7 TeV. The χ c mesons are identified through their decay to J/ψγ, with J/ψ → µ + µ − using photons that converted in the detector. A data sample, corresponding to an integrated luminosity of 1.0 fb −1 collected by the LHCb detector, is used to measure the relative prompt production rate of χ c1 and χ c2 in the rapidity range 2.0 < y < 4.5 as a function of the J/ψ transverse momentum from 3 to 20 GeV/c. First evidence for χ c0 meson production at a high-energy hadron collider is also presented.

Search for the rare decaysB0→J/ψγandBAaij1, Beteta2, Adeva3 et al. 2015Phys. Rev. DSelf Cite8000View full textAdd to dashboardCite

“…They are reconstructed following a similar strategy to that described in Ref. [16], by combining electron and positron track pairs, which can be associated with electromagnetic clusters in the ECAL and are significantly displaced from the reconstructed B decay vertex. The energy loss of electrons by emission of bremsstrahlung photons is recovered by adding the energies of reconstructed photons associated with the track.…”

Hadronic production of heavy quarkonia at LHC

“…Later the CDF collaboration also measured p T -dependence of σ (χ c2 )/σ (χ c1 ) [20]. With the launch of the LHC a new data on σ (χ c2 )/σ (χ c1 ) became available (CMS [21], LHCb run1 [22] and run 2 [23], ATLAS [24]). ATLAS collaboration also measured p T -distributions of absolute cross sections of χ c1 -and χ c2 -mesons [24].…”

“…2 shows the obtained acceptable regions for each experiment. It is seen from this figure, that experimental data can be separated into two groups that give two disjoint regions for non-perturbative parameters: first group -LHCb (run 1) [22], CMS [21] and ATLAS [24], and second group -LHCb (run 2) [23] and CDF [20]. Obviously, these two regions will merge, if we increase the errors of our estimations (by allowing a larger variation of χ 2 ).…”

“…[22,21,24,23,20] 1.41 ± 0.6 1.23 ± 0.04 3.86 Table 2: Results of ratio fit for two groups of experiments and global fit of all data.…”

“…Luchinsky decays with NRQCD parameters obtained by fitting a whole set of data on ratio [22,21,24,23,20] and CDF data on spectrum [19]. CDF data shown with filled squares.…”