  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.
