Observation of a multiplicity dependence in the $p_{\mathrm{T}}$-differential charm baryon-to-meson ratios in proton-proton collisions at $\sqrt{s}=13$ TeV

Abstract

The production of prompt $D^0$, $D_{\mathrm{s}}^{+}$, and ${\Lambda }_{\mathrm{c}}^{+}$ hadrons, and their ratios, $D_{\mathrm{s}}^{+}$/$D^0$ and ${\Lambda }_{\mathrm{c}}^{+}$/$D^0$, are measured in proton-proton collisions at $\sqrt{s}$ = 13 TeV at midrapidity ($|y|<0.5$) with the ALICE detector at the LHC. The measurements are performed as a function of the charm-hadron transverse momentum ($p_{\mathrm{T}}$) in intervals of charged-particle multiplicity, measured with two multiplicity estimators covering different pseudorapidity regions. While the strange to non-strange $D_{\mathrm{s}}^{+}$/$D^0$ ratio indicates no significant multiplicity dependence, the baryon-to-meson $p_{\mathrm{T}}$-differential ${\Lambda }_{\mathrm{c}}^{+}$/$D^0$ ratio shows a multiplicity-dependent enhancement, with a significance of 5.3$\sigma$ for $1<p_{\mathrm{T}}<12$ GeV/$c$, comparing the highest multiplicity interval with respect to the lowest one. The measurements are compared with a theoretical model that explains the multiplicity dependence by a canonical treatment of quantum charges in the statistical hadronisation approach, and with predictions from event generators that implement colour reconnection mechanisms beyond the leading colour approximation to model the hadronisation process. The ${\Lambda }_{\mathrm{c}}^{+}$/$D^0$ ratios as a function of $p_{\mathrm{T}}$ present a similar shape and magnitude as the $\Lambda /K_s^0$ ratios in comparable multiplicity intervals, suggesting a potential common mechanism for light- and charm-hadron formation, with analogous multiplicity dependence. The $p_{\mathrm{T}}$-integrated ratios, extrapolated down to $p_{\mathrm{T}}$=0, do not show a significant dependence on multiplicity within the uncertainties.

arXiv comment25 pages, 5 captioned figures, 1 table, authors from page 20, published version, figures at http://alice-publications.web.cern.ch/node/7524

References in corpus (48)

• XGBoost: A Scalable Tree Boosting System
• An Introduction to PYTHIA 8.2
• Herwig 7.0 / Herwig++ 3.0 Release Note
• Tuning PYTHIA 8.1: the Monash 2013 Tune
• Performance of the ALICE Experiment at the CERN LHC
• Heavy Ion Collisions: The Big Picture, and the Big Questions
• Enhanced production of multi-strange hadrons in high-multiplicity proton-proton collisions
• Theoretical predictions for charm and bottom production at the LHC
• Heavy-flavour and quarkonium production in the LHC era: from proton-proton to heavy-ion collisions
• Spectroscopy and Regge trajectories of heavy baryons in the relativistic quark-diquark picture
• String Formation Beyond Leading Colour
• K${}_{\mathrm{S}}^0$ and $\mathrm{\Lambda }$ production in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV
• Coalescence Models For Hadron Formation From Quark Gluon Plasma
• Inclusive Charmed-Meson Production at the CERN LHC
• Multiplicity dependence of light-flavor hadron production in pp collisions at $\sqrt{s}$ = 7 TeV
• Perturbative QCD Fragmentation Functions as a Model for Heavy-Quark Fragmentation
• Collinear Subtractions in Hadroproduction of Heavy Quarks
• Charm-Baryon Production in Proton-Proton Collisions
• Charged-particle multiplicities in proton-proton collisions at $\sqrt{s}$ = 0.9 to 8 TeV
• Combined analysis of charm-quark fragmentation-fraction measurements
• Measurement of b-hadron fractions in 13 TeV pp collisions
• Measurement of D${}^0$, D${}^{+}$, D${}^{\ast +}$ and D${}_{\mathrm{s}}^{+}$ production in Pb-Pb collisions at $\sqrt{{\mathbf{s}}_{\mathrm{NN}}}=5.02$ TeV
• Multiplicity dependence of (multi-)strange hadron production in proton-proton collisions at $\sqrt{s}$ = 13 TeV
• Multiplicity dependence of $\pi$, K, and p production in pp collisions at $\sqrt{s}=13$ TeV
• Charged-particle production as a function of multiplicity and transverse spherocity in pp collisions at $\sqrt{s}$ = 5.02 and 13 TeV
• Charm Hadrons in pp collisions at LHC energy within a Coalescence plus Fragmentation approach
• ${\Lambda }_{\mathrm{c}}^{+}$ production in pp collisions at $\sqrt{s}=7$ TeV and in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV
• Fragmentation fractions of c and b quarks into charmed hadrons at LEP
• Measurement of charm and beauty production at central rapidity versus charged-particle multiplicity in proton-proton collisions at $\sqrt{\text{s}}=7$ TeV
• First measurement of ${\Lambda }_c$ baryon production in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}$ = 200 GeV
• Measurement of ${\mathrm{D}}^0$, ${\mathrm{D}}^{+}$, ${\mathrm{D}}^{\ast +}$ and ${{\mathrm{D}}^{+}}_s$ production in pp collisions at $\sqrt{\text{s}}=5.02\mathbf{TeV}$ with ALICE
• Prompt D${}^0$, D${}^{+}$, and D${}^{\ast +}$ production in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV
• ${\mathrm{\Lambda }}_{\mathrm{c}}^{+}$ production and baryon-to-meson ratios in pp and p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV at the LHC
• Production of ${\Lambda }_{\mathrm{c}}^{+}$ baryons in proton-proton and lead-lead collisions at $\sqrt{s_{\mathrm{NN}}}=$ 5.02 TeV
• ${\Lambda }_{\mathrm{c}}^{+}$ production in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV
• Measurement of beauty and charm production in pp collisions at $\sqrt{s}=5.02$ TeV via non-prompt and prompt D mesons
• ${\Lambda }_c^{\pm }$ production in pp collisions with a new fragmentation function
• ${\mathrm{\Lambda }}_{\mathrm{c}}^{+}$ production in pp and in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV
• Measurement of prompt D${}^0$, ${\Lambda }_c^{+}$, and ${\Sigma }_c^{0,++}$(2455) production in pp collisions at $\sqrt{s}=13$ TeV
• Measurement of the $B^{\pm }$ production cross-section in pp collisions at $\sqrt{s}=$ 7 and 13 TeV
• Measurement of the total and differential inclusive B+ hadron cross sections in pp collisions at sqrt(s) = 13 TeV
• Pseudorapidity distributions of charged particles as a function of mid and forward rapidity mutiplicities in pp collisions at $\sqrt{s}$ = 5.02, 7 and 13 TeV
• Measurements of prompt charm production cross-sections in $pp$ collisions at $\sqrt{s}=5$TeV
• Measurement of the production cross section of prompt ${\Xi }_{\mathrm{c}}^0$ baryons at midrapidity in pp collisions at $\sqrt{s}$ = 5.02 TeV
• Observation of $D_s^{\pm }/D^0$ enhancement in Au+Au collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}$ = 200 GeV
• First measurement of ${\Xi }_{\mathrm{c}}^0$ production in pp collisions at $\sqrt{\mathbf{s}}$ = 7 TeV
• Measurement of D-meson production versus multiplicity in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV
• Charged-particle multiplicity dependence of charm-baryon-to-meson ratio in high-energy proton-proton collisions

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• Measurement of the production cross section of prompt ${\Xi }_{\mathrm{c}}^0$ baryons in p$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV
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