Bottom production cross section from double muonic decays of b-flavoured hadrons in 920 GeV proton-nucleus collisions

Abstract The b b ¯ production cross section in 920 GeV proton-nucleus fixed target collisions is measured by observing double muonic decays of b -flavoured hadrons in the kinematic region − 0.3 x F ( μ ) 0.15 . A total number of 83 ± 12 b b ¯ events is obtained with a likelihood fit of the signal and background simulated events to the data. The resulting cross section is σ b b ¯ = 17.5 ± 2.6 stat ± 3.3 sys nb / nucleon , or, when combined with a previous HERA-B measurement of similar precision, σ b b ¯ = 15.8 ± 1.7 stat ± 1.3 sys uncorr ± 2.0 sys corr nb / nucleon , which is consistent with recent NLO calculations.