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Abstract The total charm-quark production cross section per unit of rapidity$$\textrm{d}\sigma ({{\textrm{c}}\overline{\textrm{c}}})/\textrm{d}y$$ , and the fragmentation fractions of charm quarks to different charm-hadron species$$f(\textrm{c}\rightarrow {\textrm{h}}_{\textrm{c}})$$ , are measured for the first time in p–Pb collisions at$$\sqrt{s_\textrm{NN}} = 5.02~\text {Te}\hspace{-1.00006pt}\textrm{V} $$ at midrapidity ($$-0.96<0.04$$ in the centre-of-mass frame) using data collected by ALICE at the CERN LHC. The results are obtained based on all the available measurements of prompt production of ground-state charm-hadron species:$$\textrm{D}^{0}$$ ,$$\textrm{D}^{+}$$ ,$$\textrm{D}_\textrm{s}^{+}$$ , and$$\mathrm {J/\psi }$$ mesons, and$$\Lambda _\textrm{c}^{+}$$ and$$\Xi _\textrm{c}^{0}$$ baryons. The resulting cross section is$$ \textrm{d}\sigma ({{\textrm{c}}\overline{\textrm{c}}})/\textrm{d}y =219.6 \pm 6.3\;(\mathrm {stat.}) {\;}_{-11.8}^{+10.5}\;(\mathrm {syst.}) {\;}_{-2.9}^{+8.3}\;(\mathrm {extr.})\pm 5.4\;(\textrm{BR})\pm 4.6\;(\mathrm {lumi.}) \pm 19.5\;(\text {rapidity shape})+15.0\;(\Omega _\textrm{c}^{0})\;\textrm{mb} $$ , which is consistent with a binary scaling of pQCD calculations from pp collisions. The measured fragmentation fractions are compatible with those measured in pp collisions at$$\sqrt{s} = 5.02$$ and 13 TeV, showing an increase in the relative production rates of charm baryons with respect to charm mesons in pp and p–Pb collisions compared with$$\mathrm {e^{+}e^{-}}$$ and$$\mathrm {e^{-}p}$$ collisions. The$$p_\textrm{T}$$ -integrated nuclear modification factor of charm quarks,$$R_\textrm{pPb}({\textrm{c}}\overline{\textrm{c}})= 0.91 \pm 0.04\;\mathrm{(stat.)} ^{+0.08}_{-0.09}\;\mathrm{(syst.)} ^{+0.05}_{-0.03}\;\mathrm{(extr.)} \pm 0.03\;\mathrm{(lumi.)}$$ , is found to be consistent with unity and with theoretical predictions including nuclear modifications of the parton distribution functions.
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Measurement of the production cross section of prompt $$\Xi ^0_{\textrm{c}}$$ baryons in p–Pb collisions at $$\sqrt{s_{{\textrm{NN}}}}=5.02$$ TeV
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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- PAR ID:
- 10599245
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- Springer
- Date Published:
- Journal Name:
- The European Physical Journal C
- Volume:
- 85
- Issue:
- 1
- ISSN:
- 1434-6052
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1140/epjc/s10052-024-13531-w
