Small Angle Muon and Bottom Quark Production in pbarp Collisions at sqrt(s) = 1.8 TeV

Abstract

This Letter describes a measurement of the muon cross section originating from b quark decay in the forward rapidity range 2.4 < y(mu) < 3.2 in pbarp collisions at sqrt(s) = 1.8 TeV. The data used in this analysis were collected by the D0 experiment at the Fermilab Tevatron. We find that NLO QCD calculations underestimate b quark production by a factor of four in the forward rapidity region. A cross section measurement using muon+jet data has been included in this version of the paper.

Figures (5)

• Figure 1: The inclusive muon cross section in the forward region as a function of $p_T^{\mu}$ (per unit rapidity). The dashed line shows the expected contributions from $\pi/K$ decays.
• Figure 2: Data $p_T^{\rm rel}$ distributions for two selected $p_T^{\mu}$ ranges. The solid line shows the fit to the data, with broken lines showing contributions from $b$ quark (dashed), $c$ quark (dotted), and $\pi /K$ (dot-dashed) decay. $f_b$ is the $b$ quark fraction after $\pi /K$ subtraction (errors are statistical only).
• Figure 3: $f_b$ for muons with an associated jet as measured from data $p_T^{\rm rel}$ fits (triangles and circle) and as predicted by the NLO QCD MC (dot-dashed curve) The prediction of $f_b$ for muons without the jet requirement is shown by the solid curve with uncertainties indicated by dotted curves.
• Figure 4: The cross section for muons from $b$ quark decay as a function of $p_T^{\mu}$ (per unit rapidity) as measured with the inclusive muon sample (triangles) and its sub-sample of events that have a jet associated with the muon (circles). The solid curve is the NLO QCD prediction, with the dashed curves representing the theoretical uncertainties.
• Figure 5: The cross section of muons from $b$ quark decay as a function of $|{\rm \sl y}^{\mu}|$ for $p_T^{\mu}> 5$ GeV/$c$, and $p_T^{\mu}> 8$ GeV/$c$. The solid curves are the NLO QCD predictions, with uncertainty bands shown by the dashed lines.