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A<sc>bstract</sc> Measurements of the production cross sections of prompt D0, D+, D*+,$$ {\textrm{D}}_{\textrm{s}}^{+} $$ ,$$ {\Lambda}_{\textrm{c}}^{+} $$ , and$$ {\Xi}_{\textrm{c}}^{+} $$ charm hadrons at midrapidity in proton-proton collisions at$$ \sqrt{s} $$ = 13 TeV with the ALICE detector are presented. The D-meson cross sections as a function of transverse momentum (pT) are provided with improved precision and granularity. The ratios ofpT-differential meson production cross sections based on this publication and on measurements at different rapidity and collision energy provide a constraint on gluon parton distribution functions at low values of Bjorken-x(10−5–10−4). The measurements of$$ {\Lambda}_{\textrm{c}}^{+} $$ ($$ {\Xi}_{\textrm{c}}^{+} $$ ) baryon production extend the measuredpTintervals down topT= 0(3) GeV/c. These measurements are used to determine the charm-quark fragmentation fractions and the$$ \textrm{c}\overline{\textrm{c}} $$ production cross section at midrapidity (|y|<0.5) based on the sum of the cross sections of the weakly-decaying ground-state charm hadrons D0, D+,$$ {\textrm{D}}_{\textrm{s}}^{+} $$ ,$$ {\Lambda}_{\textrm{c}}^{+} $$ ,$$ {\Xi}_{\textrm{c}}^0 $$ and, for the first time,$$ {\Xi}_{\textrm{c}}^{+} $$ , and of the strongly-decaying J/ψmesons. The first measurements of$$ {\Xi}_{\textrm{c}}^{+} $$ and$$ {\Sigma}_{\textrm{c}}^{0,++} $$ fragmentation fractions at midrapidity are also reported. A significantly larger fraction of charm quarks hadronising to baryons is found compared to e+e−and ep collisions. The$$ \textrm{c}\overline{\textrm{c}} $$ production cross section at midrapidity is found to be at the upper bound of state-of-the-art perturbative QCD calculations.
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This content will become publicly available on March 1, 2026
First observation of strange baryon enhancement with effective energy in pp collisions at the LHC
A<sc>bstract</sc> The production of (multi-)strange hadrons is measured at midrapidity in proton-proton collisions at$$ \sqrt{s} $$ = 13 TeV as a function of the local charged-particle multiplicity in the pseudorapidity interval |η|<0.5 and of the very-forward energy measured by the ALICE Zero-Degree Calorimeters. The latter provides information on the effective energy, i.e. the energy available for particle production in the collision once subtracted from the centre-of-mass energy. The yields of$$ {\textrm{K}}_{\textrm{S}}^0 $$ ,$$ \Lambda +\overline{\Lambda} $$ , and$$ {\Xi}^{-}+{\overline{\Xi}}^{+} $$ per charged-particle increase with the effective energy. In addition, this work exploits a multi-differential approach to decouple the roles of local multiplicity and effective energy in such an enhancement. The results presented in this article provide new insights into the interplay between global properties of the collision, such as the initial available energy in the event, and the locally produced final hadronic state, connected to the charged-particle multiplicity at midrapidity. Notably, a strong increase of strange baryon production with effective energy is observed for fixed charged-particle multiplicity at midrapidity. These results are discussed within the context of existing phenomenological models of hadronisation implemented in different tunes of the PYTHIA 8 event generator.
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- Award ID(s):
- 2208883
- PAR ID:
- 10599241
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- Springer
- Date Published:
- Journal Name:
- Journal of High Energy Physics
- Volume:
- 2025
- Issue:
- 3
- ISSN:
- 1029-8479
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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