THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS
Abstract
The multiplicity dependence of jet production in pp collisions at the centre-of-mass energy of √s = 13 TeV is studied for the first time. Jets are reconstructed from charged particles using the anti-kT algorithm with resolution parameters R varying from 0.2 to 0.7. The jets are measured in the pseudorapidity range |ηjet| < 0.9 − R and inn the transverse momentum range 5 < pch < 140 GeV/c. T,jet. The multiplicity intervals are categorised by the ALICE forward detector V0. The pT differential cross section of charged-particle jets are compared to leading order (LO) and next-to-leading order (NLO) perturbative quantum chro- modynamics (pQCD) calculations. It is found that the data are better described by the NLO calculation, although the NLO prediction overestimates the jet cross section below 20 GeV/c. The cross section ratios for different R are also measured and compared to model calculations. These mea- surements provide insights into the angular dependence of jet fragmentation. The jet yield increases with increasing self-normalised charged-particle multiplicity. This increase shows only a weak dependence on jet transverse momentum and resolution parameter at the highest multiplicity. While such behaviour is qualitatively described by the present ver- sion of PYTHIA, quantitative description may require imple- menting new mechanisms for multi-particle production in hadronic collisions.
