UCLA

The production cross section of a W boson in association with two b jets is measured using a sample of proton–proton collisions at s=8TeV$$\sqrt{s} = 8{\,\mathrm{{TeV}}} $$ collected by the CMS experiment at the CERN LHC. The data sample corresponds to an integrated luminosity of 19.8fb-1$$\,\text {fb}^\text {-1}$$. The W bosons are reconstructed via their leptonic decays, W→ℓν$$\mathrm {W}\rightarrow \ell u $$, where ℓ=μ$$\ell =\mu $$ or e$$\mathrm {e}$$. The fiducial region studied contains exactly one lepton with transverse momentum pTℓ>30GeV$$p_{\mathrm {T}} ^{\ell }>30\,\mathrm{{GeV}} $$ and pseudorapidity |ηℓ|<2.1$$|\eta ^{\ell } |<2.1$$, with exactly two b jets with pT>25GeV$$p_{\mathrm {T}} >25\,\mathrm{{GeV}} $$ and |η|<2.4$$|\eta |<2.4$$ and no other jets with pT>25GeV$$p_{\mathrm {T}} >25\,\mathrm{{GeV}} $$ and |η|<4.7$$|\eta |<4.7$$. The cross section is measured to be σ(pp→W(ℓν)$$\sigma ( {{\mathrm {p}\mathrm {p}}} \rightarrow {\mathrm {W}} (\ell u )$$+bb¯)=0.64±0.03(stat)±0.10(syst)±0.06(theo)±0.02(lumi)pb$${\mathrm{{b}}\mathrm{{\overline{b}}}})= 0.64 \pm 0.03{\,\mathrm{{(stat)}}} \pm 0.10{\,\mathrm{{(syst)}}} \pm 0.06{\,\mathrm{{(theo)}}} \pm 0.02{\,\mathrm{{(lumi)}}}\,{\text {pb}}$$, in agreement with standard model predictions.