Multiplicity dependence of ₂^+ and ₂^0 production in pp collisions at s=13 TeV

A bstract The first measurement at midrapidity (| y | < 0. 5) of the production yield of the strange-charm baryons ₂^+ and ₂^0 as a function of transverse momentum (p T) in different charged-particle multiplicity classes in proton-proton collisions at s=13 TeV with the ALICE experiment at the LHC is reported. The ₂^+ baryon is reconstructed via the ₂^+ ^- ^+ ^+ decay channel in the range 4 < p T < 12 GeV /c, while the ₂^0 baryon is reconstructed via both the ₂^0 ^- ^+ and ₂^0 ^-e^+ ₄ decay channels in the range 2 < p T < 12 GeV /c. The baryon-to-meson (₂^0, +/D^0) and the baryon-to-baryon (₂^0, +/₂^+) 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 BR (₂^0 ^-e^+ ₄) /BR (₂^0 ^- ^+) 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.