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Improved Measurement of the b-bbar Production Cross Section in 920 GeV Fixed-Target Proton-Nucleus Collisions

B Collaboration·I. Abt
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Abstract

A new measurement of the b-bbar production cross section in 920 GeV proton-nucleus collisions is presented by the HERA-B collaboration. The b-bbar production is tagged via inclusive bottom quark decays into J/psi mesons, by exploiting the longitudinal separation of J/psi->ll decay vertices from the primary proton-nucleus interaction point. Both e+e- and mu+mu- channels are reconstructed, for a total of 83 +- 12 inclusive b->J/psi X events found. The combined analysis yields a b-bbar to prompt J/psi cross section ratio of ${\frac{Δσ(bbbar)}{Δσ_{\jpsi}}} = 0.032\pm 0.005 \stat \pm 0.004 \sys$ measured in the x_f acceptance (-0.35 <x_f <0.15), extrapolated to $σ(bbbar) = 14.9 \pm 2.2 \stat \pm 2.4 \sys $ nb/nucleon in the total phase space.

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B Collaboration, I. Abt. 2005-12-15. Improved Measurement of the b-bbar Production Cross Section in 920 GeV Fixed-Target Proton-Nucleus Collisions. https://doi.org/10.1103/physrevd.73.052005

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