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


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 \( \sqrt{s}=7 \) 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.


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