Charged jet cross sections and properties in proton-proton collisions at √s = 7 TeV

The differential charged jet cross sections, jet fragmentation distributions, and jet shapes are measured in minimum bias proton-proton collisions at center-of-mass energy √s = 7 TeV using the ALICE detector at the LHC. Jets are reconstructed from charged particle momenta in the midrapidity region using the sequential recombination k_T and anti-k_T as well as the SISCone jet finding algorithms with several resolution parameters in the range R = 0.2–0.6. Differential jet production cross sections measured withthe three jet finders are in agreement in the transverse momentum (p_T) interval 20 < p_T^jet,ch < 100 GeV/c. They are also consistent with prior measurements carried out at the LHC by the ATLAS Collaboration. The jet charged particle multiplicity rises monotonically with increasing jet p_T  in qualitative agreement with prior observations at lower energies. The transverse profiles of leading jets are investigated using radial momentum density distributions as well as distributions of the average radius containing 80% (⟨R₈₀⟩) of the reconstructed jet p_T  The fragmentation of leading jets with R = 0.4 using scaled p_T spectra of the jet constituents is studied. The measurements are compared to model calculations from event generators (PYTHIA, PHOJET, HERWIG). The measured radial density distributions and ⟨ R₈₀⟩ distributions are well described by the PYTHIA model (tune Perugia-2011). The fragmentation distributions are better described by HERWIG.