1 research outputs found
First measurement of <math><msubsup><mi mathvariant="normal">Î</mi><mrow><mi>c</mi></mrow><mo>+</mo></msubsup></math> production down to <math><mrow><msub><mi>p</mi><mi>T</mi></msub><mo>=</mo><mn>0</mn></mrow></math> in <math><mrow><mi>p</mi><mi>p</mi></mrow></math> and <math><mi>p</mi></math>-Pb collisions at <math><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>5.02</mn></mrow></math> TeV
International audienceThe production of prompt Îc+ baryons has been measured at midrapidity in the transverse momentum interval 0<pT<1 GeV/c for the first time, in pp and pâPb collisions at a center-of-mass energy per nucleon-nucleon collision sNN=5.02TeV. The measurement was performed in the decay channel Îc+âpKS0 by applying new decay reconstruction techniques using a Kalman-Filter vertexing algorithm and adopting a machine-learning approach for the candidate selection. The pT-integrated Îc+ production cross sections in both collision systems were determined and used along with the measured yields in PbâPb collisions to compute the pT-integrated nuclear modification factors RpPb and RAA of Îc+ baryons, which are compared to model calculations that consider nuclear modification of the parton distribution functions. The Îc+/D0 baryon-to-meson yield ratio is reported for pp and pâPb collisions. Comparisons with models that include modified hadronization processes are presented, and the implications of the results on the understanding of charm hadronization in hadronic collisions are discussed. A significant (3.7Ï) modification of the mean transverse momentum of Îc+ baryons is seen in pâPb collisions with respect to pp collisions, while the pT-integrated Îc+/D0 yield ratio was found to be consistent between the two collision systems within the uncertainties