D^+_s meson production at central rapidity in proton–proton collisions at sqrt(s) = 7 TeV

The p T-differential inclusive production cross section of the prompt charm-strange meson Ds+ in the rapidity range |y|<0.5 was measured in proton-proton collisions at s=7 TeV at the LHC using the ALICE detector. The analysis was performed on a data sample of 2.98×10 8 events collected with a minimum-bias trigger. The corresponding integrated luminosity is L int=4.8nb -1. Reconstructing the decay Ds+→φπ+, with φ→K -K +, and its charge conjugate, about 480 Ds± mesons were counted, after selection cuts, in the transverse momentum range 2<p T<12GeV/c. The results are compared with predictions from models based on perturbative QCD. The ratios of the cross sections of four D meson species (namely D 0, D +, D *+ and D s +) were determined both as a function of p T and integrated over p T after extrapolating to full p T range, together with the strangeness suppression factor in charm fragmentation. The obtained values are found to be compatible within uncertainties with those measured by other experiments in e +e -, ep and pp interactions at various centre-of-mass energies.