Charged jet cross section and fragmentation in proton-proton collisions at √s = 7 TeV

Abstract

We report the differential charged jet cross section and jet fragmentation distributions measured with the ALICE detector in proton-proton collisions at a center-of-mass energy ffiffiffi s p ¼ 7 TeV. Jets with pseudorapidity jηj < 0.5 are reconstructed from charged particles using the anti-kT jet-finding algorithm with a resolution parameter R ¼ 0.4. The jet cross section is measured in the transverse momentum interval 5 ≤ pch jet T < 100 GeV=c. Jet fragmentation is studied measuring the scaled transverse momentum spectra of the charged constituents of jets in four intervals of jet transverse momentum between 5 and 30 GeV=c. The measurements are compared to calculations from the PYTHIA model as well as next-to-leading-order perturbative QCD calculations with POWHEG+PYTHIA8. The charged jet cross section is well described by POWHEG for the entire measured range of pch jet T . For pch jet T > 40 GeV=c, the PYTHIA calculations also agree with the measured charged jet cross section. PYTHIA6 simulations describe the fragmentation distributions to 15%. Larger discrepancies are observed for PYTHIA8.