Measurement of the inclusive b production cross section in pp collisions at $\sqrt{s}$ = 7 TeV

This paper presents the measurement of inclusive b production cross section at the central mass energy of 7 TeV in CMS from the PAS BPH-10-007 and PAS BPH-10-009. The measurement are based on two different methods, one of which uses inclusive jets with secondary vertex tagging and the b-jet reconstruction efficiency and the other of which selects a sample of events containing jets and at least one muon whose the transverse momentum with respect to the closest jet axis discriminates b events from the background. At the every beginning of CMS run, $60 \ \textrm{nb} ^{-1}$ data is used in the b-jet cross section study and jets in the region of $18 \textrm{GeV} /c<p_T<300 \textrm{GeV} /c$ and tracker acceptance $\mid y \mid <2.0$ are constructed with the anti-$k_T$ algorithm within cone size $R=0.5$ using Particle Flow objects. The systematic uncertainty is at 21\% and the statistical one is 2\%. For the jet with muon cross section is measured with $8.1 \ \textrm{nb} ^{-1}$. Events are selected by requiring a good reconstructed muon and the systematic uncertainty is limited to be 20\%. At last, both results will compare with the theoretic predictions of Pythia and QCD Monte Carlo predictions at next-to-leading order (NLO).