Study of flavor dependence of the baryon-to-meson ratio in proton-proton collisions at √s=13 TeV

Abstract

The production cross sections of ${\mathrm{D}}^{0}$ and ${\mathrm{\ensuremath{\Lambda}}}_{\mathrm{c}}^{+}$ hadrons originating from beauty-hadron decays (i.e., nonprompt) were measured for the first time at midrapidity ($|y|<0.5$) by the ALICE Collaboration in proton-proton collisions at a center-of-mass energy $\sqrt{s}=13\text{ }\text{ }\mathrm{TeV}$. They are described within uncertainties by perturbative QCD calculations employing the fragmentation fractions of beauty quarks to baryons measured at forward rapidity by the LHCb Collaboration. The $\mathrm{b}\overline{\mathrm{b}}$ production cross section per unit of rapidity at midrapidity, estimated from these measurements, is $\mathrm{d}{\ensuremath{\sigma}}_{\mathrm{b}\overline{\mathrm{b}}}/\mathrm{d}y{|}_{|y|<0.5}=83.1\ifmmode\pm\else\textpm\fi{}3.5(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}\phantom{\rule{0ex}{0ex}}5.4(\mathrm{syst}{)}_{\ensuremath{-}3.2}^{+12.3}(\text{extrap})\text{ }\text{ }\mathrm{\ensuremath{\mu}}\mathrm{b}$. The baryon-to-meson ratios are computed to investigate the hadronization mechanism of beauty quarks. The nonprompt ${\mathrm{\ensuremath{\Lambda}}}_{\mathrm{c}}^{+}/{\mathrm{D}}^{0}$ production ratio has a similar trend to the one measured for the promptly produced charmed particles and to the $\mathrm{p}/{\ensuremath{\pi}}^{+}$ and $\mathrm{\ensuremath{\Lambda}}/{\mathrm{K}}_{\mathrm{S}}^{0}$ ratios, suggesting a similar baryon-formation mechanism among light, strange, charm, and beauty hadrons. The ${p}_{\mathrm{T}}$ -integrated nonprompt ${\mathrm{\ensuremath{\Lambda}}}_{\mathrm{c}}^{+}/{\mathrm{D}}^{0}$ ratio is found to be significantly higher than the one measured in ${\mathrm{e}}^{+}{\mathrm{e}}^{\ensuremath{-}}$ collisions.