Measurement of the production cross section of prompt $\Xi^0_{\rm c}$ baryons at midrapidity in pp collisions at $\sqrt{s}$ = 5.02 TeV

TL;DR

This paper measures the production rate of prompt $ ext{Xi}^0_{ ext{c}}$ baryons in proton-proton collisions at 5.02 TeV, comparing results with various models to understand charm hadronization.

Contribution

It provides the first detailed measurement of $ ext{Xi}^0_{ ext{c}}$ production at LHC energies and compares it with models including an extended set of charm-baryon states.

Findings

The $ ext{Xi}^0_{ ext{c}}$ to $ ext{D}^0$ ratio is approximately 0.20.

Results suggest modifications in charm fragmentation in pp collisions.

Measurements are consistent with models including quark coalescence.

Abstract

The transverse momentum ($p_{\rm T}$) differential cross section of the charm-strange baryon $\Xi^0_{\rm c}$ is measured at midrapidity ($|y|<$ 0.5) via its semileptonic decay into ${\rm e^{+}}\Xi^{-}\nu_{\rm e}$ in pp collisions at $\sqrt{s}$ = 5.02 TeV with the ALICE detector at the LHC. The ratio of the $p_{\rm T}$-differential $\Xi^0_{\rm c}$-baryon and ${\rm D^0}$-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 $p_{\rm T}$-integrated cross section of prompt $\Xi^0_{\rm c}$-baryon production at midrapidity is also reported, which is used to calculate the baryon-to-meson ratio $\Xi^0_{\rm c}/{\rm D^0} = 0.20 \pm 0.04~{\rm (stat.)} ^{+0.08}_{-0.07}~{\rm (syst.)}$. These results provide an additional indication of a modification of the charm fragmentation from $\rm e^+e^-$ and $\rm e^{-}p$ collisions to pp collisions.