engleski

Λ(+)(c) Production and Baryon-to-Meson Ratios in pp and p-Pb Collisions at √sNN=5.02 TeV at the LHC

The prompt production of the charm baryon Λ(c+) and the Λ(c)(+)/D-0 production ratios were measured at midrapidity with the ALICE detector in pp and (p)-Pb collisions at √sNN = 5.02 TeV. These new measurements show a clear decrease of the Λ(+)(c)/D-0 ratio with increasing transverse momentum (p(T)) in both collision systems in the range 2 < P-T < 12 GeV/c, exhibiting similarities with the light-flavor baryon-tomeson ratios p/pi and Λ/K-S(0). At low p(T), predictions that include additional color-reconnection mechanisms beyond the leading- color approximation, assume the existence of additional higher-mass charm- baryon states, or include hadronization via coalescence can describe the data, while predictions driven by charmquark fragmentation processes measured in e(+) e(-) and e(-) p collisions significantly underestimate the data. The results presented in this Letter provide significant evidence that the established assumption of universality (colliding-system independence) of parton-to-hadron fragmentation is not sufficient to describe charm-baryon production in hadronic collisions at LHC energies.

multiplicity dependence ; rapidity ; proton ; kaon ; pion

nije evidentirano