Transverse momentum spectra of b jets in pPb collisions at sqrt(s[NN]) = 5.02 TeV

TL;DR

This study measures b jet transverse momentum spectra in pPb collisions at 5.02 TeV, compares results to pp simulations, and evaluates nuclear modification factors to understand cold nuclear matter effects.

Contribution

First measurement of b jet spectra in pPb collisions at the LHC using secondary vertex tagging techniques.

Findings

Nuclear modification factor around 1.22 indicating slight enhancement.

Results consistent with perturbative QCD predictions.

Provides baseline for understanding heavy-flavor production in nuclear collisions.

Abstract

We present a measurement of b jet transverse momentum (pt) spectra in proton-lead (pPb) collisions using a dataset corresponding to about 35 inverse nanobarns collected with the CMS detector at the LHC. Jets from b quark fragmentation are found by exploiting the long lifetime of hadrons containing a b quark through tagging methods using distributions of the secondary vertex mass and displacement. Extracted cross sections for b jets are scaled by the effective number of nucleon-nucleon collisions and are compared to a reference obtained from PYTHIA simulations of pp collisions. The PYTHIA-based estimate of the nuclear modification factor is found to be 1.22 +/- 0.15 (stat + syst pPb) +/- 0.27 (syst PYTHIA) averaged over all jets with pt between 55 and 400 GeV/c and with abs(eta[lab]) < 2. We also compare this result to predictions from models using perturbative calculations in quantum chromodynamics.