Measurement of the production cross section of prompt Xi(0)(c) baryons at midrapidity in pp collisions at root s=5.02 TeV

The transverse momentum (pT) differential cross section of the charm-strange baryon \u39e0c is measured at midrapidity (|y| < 0.5) via its semileptonic decay into e+\u39e 12\u3bde in pp collisions at s 1a = 5.02 TeV with the ALICE detector at the LHC. The ratio of the pT-differential \u39e0c-baryon and D0-meson production cross sections is also reported. The measurements are compared with simulations with different tunes of the PYTHIA 8 event generator, with predictions from a statistical hadronisation model (SHM) with a largely augmented set of charm-baryon states beyond the current lists of the Particle Data Group, and with models including hadronisation via quark coalescence. The pT-integrated cross section of prompt \u39e0c-baryon production at midrapidity is also reported, which is used to calculate the baryon-to-meson ratio \u39e0c/D0 = 0.20 \ub1 0.04 (stat.)+0.08 120.07 (syst.). These results provide an additional indication of a modification of the charm fragmentation from e+e 12 and e 12p collisions to pp collisions

Measurement of the Cross Sections of Xi(0)(c) and Xi(+)(c) Baryons and of the Branching-Fraction Ratio BRo (Xi(0)(c) -> Xi(-) e(+) nu(e))/BR(Xi(0)(c) -> Xi(-) pi(+)) in pp Collisions at root s=13 TeV

The pT-differential cross sections of prompt charm-strange baryons Ξ0c and Ξ+c were measured at midrapidity (|y|<0.5) in proton-proton (pp) collisions at a center-of-mass energy √s=13  TeV with the ALICE detector at the LHC. The Ξ0c baryon was reconstructed via both the semileptonic decay (Ξ−e+νe) and the hadronic decay (Ξ−π+) channels. The Ξ+c baryon was reconstructed via the hadronic decay (Ξ−π+π+) channel. The branching-fraction ratio BR(Ξ0c→Ξ−e+νe)/BR(Ξ0c→Ξ−π+)=1.38±0.14(stat)±0.22(syst) was measured with a total uncertainty reduced by a factor of about 3 with respect to the current world average reported by the Particle Data Group. The transverse momentum (pT) dependence of the Ξ0c- and Ξ+c-baryon production relative to the D0 meson and to the Σ0,+,++c- and Λ+c-baryon production are reported. The baryon-to-meson ratio increases toward low pT up to a value of approximately 0.3. The measurements are compared with various models that take different hadronization mechanisms into consideration. The results provide stringent constraints to these theoretical calculations and additional evidence that different processes are involved in charm hadronization in electron-positron (e+e−) and hadronic collisions.publishedVersio