Measurement of Prompt D^{0}, Λ_{c}^{+}, and Σ_{c}^{0,++}(2455) Production in Proton-Proton Collisions at sqrt[s]=13 TeV

The p(T)-differential production cross sections of prompt D-0, Lambda(c)+, and Sigma(0,++)(c) (2455) charmed hadrons are measured at midrapidity (vertical bar y vertical bar < 0.5) in pp collisions at root s. = 13 TeV. This is the first measurement of Sigma(0,++)(c) production in hadronic collisions. Assuming the same production yield for the three Sigma(0,++)(c) isospin states, the baryon-to-meson cross section ratios Sigma(0,+,++)(c)/D-0 and Lambda(+)(c)/D-0 are calculated in the transverse momentum (p(T)) intervals 2 < p(T) < 12 and 1 < p(T) < 24 GeV/c. Values significantly larger than in e(+)e(-) collisions are observed, indicating for the first time that baryon enhancement in hadronic collisions also extends to the Sigma(c). The feed-down contribution to Lambda(+)(c) production from Sigma(0,+,++)(c) is also reported and is found to be larger than in e(+)e(-) collisions. The data are compared with predictions from event generators and other phenomenological models, providing a sensitive test of the different charm-hadronization mechanisms implemented in the models.