  The cross section for jets from b quarks produced with a W boson has been
measured in ppbar collision data from 1.9/fb of integrated luminosity recorded
by the CDF II detector at the Tevatron. The W+b-jets process poses a
significant background in measurements of top quark production and prominent
searches for the Higgs boson. We measure a b-jet cross section of 2.74 +-
0.27(stat.) +- 0.42(syst.) pb in association with a single flavor of leptonic W
boson decay over a limited kinematic phase space. This measured result cannot
be accommodated in several available theoretical predictions.
