The prompt production of charmonium χcand J/ψ states is studied in proton–proton collisions at a centre-of-mass energy of root s=7 TeV at the Large Hadron Collider. The χc and J/ψ mesons are identified through their decays χc→J/ψγ andJ/ψ→μ+μ− using 36 pb−136 pb−1 of data collected by the LHCb detector in 2010. The ratio of the prompt production cross-sections for χc and J/ψ, σ(χc→J/ψγ)/σ(J/ψ), is determined as a function of the J/ψ transverse momentum in the range 2<pT(J/ψ)<15 GeV/c. The results are in excellent agreement with next-to-leading order non-relativistic expectations and show a significant discrepancy compared with the colour singlet model prediction at leading order, especially in the low pT(J/ψ) region.
Measurement of the ratio of prompt chi(c) to J/psi production in pp collisions at root s=7 TeV
CARDINALE, ROBERTA;FONTANELLI, FLAVIO;PATRIGNANI, CLAUDIA;PETROLINI, ALESSANDRO;SANNINO, MARIO;
2012-01-01
Abstract
The prompt production of charmonium χcand J/ψ states is studied in proton–proton collisions at a centre-of-mass energy of root s=7 TeV at the Large Hadron Collider. The χc and J/ψ mesons are identified through their decays χc→J/ψγ andJ/ψ→μ+μ− using 36 pb−136 pb−1 of data collected by the LHCb detector in 2010. The ratio of the prompt production cross-sections for χc and J/ψ, σ(χc→J/ψγ)/σ(J/ψ), is determined as a function of the J/ψ transverse momentum in the range 2I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.