2024/11/15 by ALICE Collaboration
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #Nuclear Experiment (nucl-ex)
paper · doi:10.48550/arxiv.2411.10104
The distribution of angular correlations between prompt charm hadrons and primary charged particles in pp collisions is sensitive to the charm-quark hadronisation process. In this letter, charm-baryon correlations are measured for the first time by studying the azimuthal-angle difference between charged particles and prompt Λ\rm c+ baryons produced in pp collisions at a centre-of-mass energy of √(s) = 13 TeV, with the ALICE detector. Λ\rm c+ baryons are reconstructed at midrapidity (|y| < 0.5) in the transverse-momentum interval 3 < p\rm T < 16 GeV/c, and correlated with charged particles with p\rm T > 0.3 GeV/c and pseudorapidity |η| < 0.8. For 3< p\rm T^Λ\rm c+,\rm D <5 GeV/c, the comparison with published measurements of D-meson and charged-particle correlations in the same collision system hints at a larger number of low-momentum particles associated with Λ\rm c+-baryon triggers than with D-meson triggers, both in the collinear and opposite directions with respect to the trigger particle. These differences can be quantified by the comparison of the properties of the near- and away-side correlation peaks, and are not reproduced by predictions of various Monte Carlo event generators, generally underpredicting the associated particle yields at p\rm T\rm assoc<1 GeV/c. This tension between Λ\rm c+-baryon and D-meson associated peak yields could suggest a modified fragmentation of the charm quark, or a different hadronisation process, when a charm baryon is produced in the final state.