Michael Lauterbach

This paper presents measurements of the polarization of muons produced very near the point of proton - nucleon interaction. The experiment utilized a 400 GeV proton beam available in the Proton Central area of Fermilab. Muons were produced by the interaction of these protons with a variable density copper target. Extrapolation to infinite target density allowed elimination of contributions due to muons from meson decay. Measurements were made upon muons produced in the forward direction with energies near 185 GeV and upon muons produced with transverse momenta near 1.9 GeV/c and an energy of 54 GeV. In the first case only the longitudinal polarization was measured: P = - 0.01 ± 0.14. Under the second set of kinematic conditions both the longitudinal and transverse polarization were measured: P_L = - 0.06 ± 0.16, P_T = - 0.01 ± 0.11. These null measurements suggest that an electromagnetic process is the dominant mechanism for prompt muon production. The measurements also indicate an upper limit of Bμ ( D° ) σ_D° + B_μ (D⁺) σ_D⁺ < 6.7 × 10_-8 barns may be placed upon the production cross section for D particles.