Charm-Baryon Production in Proton-Proton Collisions

Abstract

Recent measurements of charm-baryon production in proton-proton collisions at the LHC have found a surprisingly large yield relative to those of $D$-mesons. We propose that this observation can be explained by the statistical hadronization model (SHM), by employing a largely augmented set of charm-baryon states beyond the current listings of the particle data group. We estimate the additional states using guidance from the relativistic quark model and from lattice QCD. Using charm- and strange-quark fugacity factors to account for the well-known suppression of heavy flavor in elementary collisions, we compute the yields and spectra of $D$, $D_s$ and ${\Lambda }_c$ hadrons in proton-proton collisions at $\sqrt{s}=5$\,TeV. Our main finding is that the enhanced feeddown from excited charm baryons can account for the ${\Lambda }_c/D^0$ ratio measured by ALICE at midrapidity, with some caveat for the forward-rapidity LHCb data. Furthermore, assuming independent fragmentation of charm quarks but with the hadronic ratios fixed by the SHM, the measured transverse-momentum ($p_T$) spectra of $D$-mesons and ${\Lambda }_c$ can also be described; in particular, the low-$p_T$ enhancement in the observed ${\Lambda }_c/D^0$ ratio is attributed to the enhanced feeddown from "missing" charm-baryon states. We comment on the implications of these findings for measurements of $D_s$ and ${\Lambda }_c$ in heavy-ion collisions.

7 pages, 3 figures; Ref.[17] updated

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Cited by in corpus (7)

• Further developments of a multi-phase transport model for relativistic nuclear collisions
• ${\Lambda }_c^{\pm }$ production in pp collisions with a new fragmentation function
• Charged-particle multiplicity dependence of charm-baryon-to-meson ratio in high-energy proton-proton collisions
• Recent ALICE results on charm production and hadronisation
• Event-activity dependent production of strange and non-strange charmed baryons in the enhanced color-reconnection scheme
• Heavy flavour production and spectroscopy
• First measurement of ${\mathrm{\Omega }}_{\mathrm{c}}^0$ production in pp collisions at $\sqrt{s}=13$ TeV with ALICE