Inclusive particle production in e+e- interactions at 3.8 and 4.8 GeV

An experiment is described which measured the inclusive momentum spectra for hadrons and muons produced in e+e- interactions at total center of mass energies of 3.8 and 4.8 GeV. The experiment was performed at the SPEAR electron-positiron storage ring at the Stanford Linear Accelerator Center. It consisted of a single-arm spectrometer, with additional apparatus to measure charged multiplicities and to tag collinear muon and electron pairs. The Lorentz-invariant cross section for hadrons is found to exhibit Feynman scaling at all measured momenta. The invariant cross sections for pions, kaons and protons fell along the same exponential energy curve, exhibiting a characteristic hadron temperature of kT = 0.19 GeV. Bjorken scaling was found to hold separately for pions and for kaons for x identical with 2E/√S greater than 0.4; however, the x-dependences of the two cross sections are significantly different. Results are also presented for the inclusive momentum distributions of the hadron charged multiplicity. An examination of inclusive muon production found the presence of a small anomalous muon signal for two-prong events noncoplanar by more than 200 and with p/sub μ/ greater than 1.05 GeV/c: d sigma/dΩvertical bar/sub 900/ = 17/sup +12//sub -9/ pb/sr. Known processes accounted for the observed muon events having charged multiplicity greater than 2, giving an upper limit at the 95 percent confidence level of d sigma/dΩvertical bar/sub 900/ less than 7.5 pb/sr for any new process