Measurement of inclusive charged-particle b-jet production in pp and p-Pb collisions at $$ \sqrt{s_{\mathrm{NN}}} $$ = 5.02 TeV

Abstract

A measurement of the inclusive b-jet production cross section is presented in pp and p-Pb collisions at $$ \sqrt{s_{\mathrm{NN}}} $$ s NN = 5.02 TeV, using data collected with the ALICE detector at the LHC. The jets were reconstructed in the central rapidity region |η| < 0.5 from charged particles using the anti-kT algorithm with resolution parameter R = 0.4. Identification of b jets exploits the long lifetime of b hadrons, using the properties of secondary vertices and impact parameter distributions. The pT-differential inclusive production cross section of b jets, as well as the corresponding inclusive b-jet fraction, are reported for pp and p-Pb collisions in the jet transverse momentum range 10 ≤ pT,ch jet≤ 100 GeV/c, together with the nuclear modification factor, $$ {R}_{\mathrm{pPb}}^{\mathrm{b}-\mathrm{jet}} $$ R pPb b − jet . The analysis thus extends the lower pT limit of b-jet measurements at the LHC. The nuclear modification factor is found to be consistent with unity, indicating that the production of b jets in p-Pb at $$ \sqrt{s_{\mathrm{NN}}} $$ s NN = 5.02 TeV is not affected by cold nuclear matter effects within the current precision. The measurements are well reproduced by POWHEG NLO pQCD calculations with PYTHIA fragmentation.

The Partonic Origin of Multiplicity Scaling in Heavy and Light Flavor Jets

“…The reconstructed jets were categorized in 20 different p jet T ranges, from 15 GeV up to 400 GeV. In the case of the charm and beauty jet samples, the corresponding heavy quark was required to fall within the cone of the selected jet, similarly to jet-tagging methods that are utilized in the experiment [29,30].…”

Defining the Underlying-Event Activity in the Presence of Heavy-Flavour Processes in Proton-Proton Collisions at LHC Energies

“…(Note that R influences the amount of background picked up by the jet clustering algorithm as well as the fraction of the full parton shower is typically contained in the jet. This analysis uses R = 0.4, a choice employed by several inclusive and heavy-flavour jet analyses [27,28]). The jets were required to be fully contained within the pseudorapidity region of |η| < 0.8.…”

Measurement of inclusive charged-particle jet production in pp and p-Pb collisions at $$ \sqrt{s_{\textrm{NN}}} $$ = 5.02 TeV

“…In-bunch pileup events, where multiple interactions occur in the same bunch crossing, are rejected by requiring that only a single primary vertex is reconstructed with the SPD in the event [24]. For the data samples considered in this paper, pileup events amount to less than 1% of the event sample both in pp and p-Pb collisions [40]. Accepted events are required to have the reconstructed primary vertex position along the beam axis within 10 cm from the center of the detector [24].…”

“…The influence of the statistical fluctuations on the systematic uncertainties of the raw spectrum was suppressed by using pseudo-experiments as done in refs. [40,63]. For each source JHEP05(2024)041 of uncertainty, several randomized instances of the raw jet p ch T,jet spectrum were generated by variations around the measured central value in each bin using a Gaussian distribution, with σ taken to be the uncorrelated statistical error in the bin.…”