Multiplicity dependence of and production in pp collisions at TeV

Abstract

The first measurement at midrapidity (|y| < 0.5) of the production yield of the strange-charm baryons and as a function of transverse momentum (pT) in different charged-particle multiplicity classes in proton-proton collisions at TeV with the ALICE experiment at the LHC is reported. The baryon is reconstructed via the decay channel in the range 4 < pT< 12 GeV/c, while the baryon is reconstructed via both the and decay channels in the range 2 < pT< 12 GeV/c. The baryon-to-meson and the baryon-to-baryon production yield ratios show no significant dependence on multiplicity. In addition, the observed yield ratios are not described by theoretical predictions that model charm-quark fragmentation based on measurements at e+e− and e−p colliders, indicating differences in the charm-baryon production mechanism in pp collisions. A comparison with different event generators and tunings, including different modelling of the hadronisation process, is also discussed. Moreover, the branching-fraction ratio of is measured as 0.825 ± 0.094 (stat.) ± 0.081 (syst.). This value supersedes the previous ALICE measurement, improving the statistical precision by a factor of 1.6.