A-dependence of low-mass muon pair production in 300 GeV/c p and 320 GeV/cπ− interactions

Abstract The A -dependence of inclusive μ + μ − production is measured in the kinematical region 2 m μ ⩽ m ( μ + μ − ) ⪅1.5 GeV/ c 2 , 0.1≲ x F ( μ + μ − ) ≲0.6, using a 300 GeV/ c p beam and a 320 GeV/ c π − beam, on Al, Fe, and U targets. Assuming that the production cross section varies as A α , we obtain α =0.68±0.03 −0.05 +0.02 for the beam and α =0.8+-0.02 −0.05 +0.02 for the the π − beam.