Λc+ production in pp and in p -Pb collisions at sNN =5.02 TeV

Abstract

The production cross section of prompt ${\mathrm{\ensuremath{\Lambda}}}_{c}^{+}$ charm baryons was measured with the ALICE detector at the LHC at midrapidity in proton-proton ($pp$) and proton-lead ($p\text{--Pb}$) collisions at a center-of-mass energy per nucleon pair of $\sqrt{{s}_{\mathrm{NN}}}=5.02\phantom{\rule{0.16em}{0ex}}\mathrm{TeV}$. The ${\mathrm{\ensuremath{\Lambda}}}_{c}^{+}$ and $\overline{\mathrm{\ensuremath{\Lambda}}}{}_{c}^{\ensuremath{-}}$ baryons were reconstructed in the hadronic decay channels ${\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}p{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ and ${\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}p{K}_{S}^{0}$ and respective charge conjugates. The measured differential cross sections as a function of transverse momentum (${p}_{T}$) and the ${p}_{T}$-integrated ${\mathrm{\ensuremath{\Lambda}}}_{c}^{+}$ production cross section in $pp$ and in $p\text{--Pb}$ collisions are presented. The ${\mathrm{\ensuremath{\Lambda}}}_{c}^{+}$ nuclear modification factor (${R}_{p\mathrm{Pb}}$), calculated from the cross sections in $pp$ and in $p\text{--Pb}$ collisions, is presented and compared with the ${R}_{p\mathrm{Pb}}$ of $D$ mesons. The ${\mathrm{\ensuremath{\Lambda}}}_{c}^{+}/{D}^{0}$ ratio is also presented and compared with the light-flavor baryon-to-meson ratios $p/\ensuremath{\pi}$ and $\mathrm{\ensuremath{\Lambda}}/{K}_{S}^{0}$, and measurements from other LHC experiments. The results are compared to predictions from model calculations and Monte Carlo event generators.