Prompt Muon-Neutrino Production in a 400-GeV Proton Beam-Dump Experiment

Abstract

The prompt ${\nu }_{\mu }$ and ${\overline{\nu }}_{\mu }$ flux produced by 400-GeV protons has been measured with a detector located 56 m from a tungsten target. The cross section for the hadronic production of charm is determined to be 27±4±5 μb/nucleon subject to the following assumptions: $D\overline{D}$ production only; $A^1$ variation of cross section; and a parametrization of the $D$-production cross section which is ${\mathrm{}(1-x)\mathrm{}}^4\exp (-2\mathrm{}{m}_{\perp })$. The ratio of prompt ${\overline{\nu }}_{\mu }$ flux to prompt ${\nu }_{\mu }$ is measured to be 1.12±0.24±0.17, consistent with predominantly $D\overline{D}$ production.