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Abstract The transverse momentum ($$p_{\textrm{T}}$$ ) differential production cross section of the promptly produced charm-strange baryon$$\mathrm {\Xi _{c}^{0}}$$ (and its charge conjugate$$\overline{\mathrm {\Xi _{c}^{0}}}$$ ) is measured at midrapidity via its hadronic decay into$$\mathrm{\pi ^{+}}\Xi ^{-}$$ in p–Pb collisions at a centre-of-mass energy per nucleon–nucleon collision$$\sqrt{s_{\textrm{NN}}}~=~5.02$$ TeV with the ALICE detector at the LHC. The$$\mathrm {\Xi _{c}^{0}}$$ nuclear modification factor ($$R_{\textrm{pPb}}$$ ), calculated from the cross sections in pp and p–Pb collisions, is presented and compared with the$$R_{\textrm{pPb}}$$ of$$\mathrm {\Lambda _{c}^{+}}$$ baryons. The ratios between the$$p_{\textrm{T}}$$ -differential production cross section of$$\mathrm {\Xi _{c}^{0}}$$ baryons and those of$$\mathrm {D^0}$$ mesons and$$\mathrm {\Lambda _{c}^{+}}$$ baryons are also reported and compared with results at forward and backward rapidity from the LHCb Collaboration. The measurements of the production cross section of prompt$$\Xi ^0_\textrm{c}$$ baryons are compared with a model based on perturbative QCD calculations of charm-quark production cross sections, which includes only cold nuclear matter effects in p–Pb collisions, and underestimates the measurement by a factor of about 50. This discrepancy is reduced when the data is compared with a model that includes string formation beyond leading-colour approximation or in which hadronisation is implemented via quark coalescence. The$$p_{\textrm{T}}$$ -integrated cross section of prompt$$\Xi ^0_\textrm{c}$$ -baryon production at midrapidity extrapolated down to$$p_{\textrm{T}}$$ = 0 is also reported. These measurements offer insights and constraints for theoretical calculations of the hadronisation process. Additionally, they provide inputs for the calculation of the charm production cross section in p–Pb collisions at midrapidity.
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Light-flavor particle production in high-multiplicity pp collisions at $$ \sqrt{\textrm{s}} $$ = 13 TeV as a function of transverse spherocity
A<sc>bstract</sc> Results on the transverse spherocity dependence of light-flavor particle production (π, K, p,ϕ, K*0,$$ {\textrm{K}}_{\textrm{S}}^0 $$ , Λ, Ξ) at midrapidity in high-multiplicity pp collisions at$$ \sqrt{s} $$ = 13 TeV were obtained with the ALICE apparatus. The transverse spherocity estimator$$ \left({S}_{\textrm{O}}^{p_{\textrm{T}}=1}\right) $$ categorizes events by their azimuthal topology. Utilizing narrow selections on$$ {S}_{\textrm{O}}^{p_{\textrm{T}}=1} $$ , it is possible to contrast particle production in collisions dominated by many soft initial interactions with that observed in collisions dominated by one or more hard scatterings. Results are reported for two multiplicity estimators covering different pseudorapidity regions. The$$ {S}_{\textrm{O}}^{p_{\textrm{T}}=1} $$ estimator is found to effectively constrain the hardness of the events when the midrapidity (|η| < 0.8) estimator is used. The production rates of strange particles are found to be slightly higher for soft isotropic topologies, and severely suppressed in hard jet-like topologies. These effects are more pronounced for hadrons with larger mass and strangeness content, and observed when the topological selection is done within a narrow multiplicity interval. This demonstrates that an important aspect of the universal scaling of strangeness enhancement with final-state multiplicity is that high-multiplicity collisions are dominated by soft, isotropic processes. On the contrary, strangeness production in events with jet-like processes is significantly reduced. The results presented in this article are compared with several QCD-inspired Monte Carlo event generators. Models that incorporate a two-component phenomenology, either through mechanisms accounting for string density, or thermal production, are able to describe the observed strangeness enhancement as a function of$$ {S}_{\textrm{O}}^{p_{\textrm{T}}=1} $$ .
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- PAR ID:
- 10514233
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- ink.springer.com
- Date Published:
- Journal Name:
- Journal of High Energy Physics
- Volume:
- 2024
- Issue:
- 5
- ISSN:
- 1029-8479
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1007/JHEP05(2024)184
