The two reactions np .-->. nn.pi. and np .-->. pp.pi.− were studied at 790 MeV (incident neutron energy). Pion spectra were measured at 10 different angles with a multiwire proportional chamber spectrometer. Approximately 100,000 events were analyzed. The angular distribution of pions in the np center of momentum system (d sigma/d.cap omega.*) was given by ((123.1 +- 2.7) + (88.3 +- 4.9)cos2(theta*))(.mu.b/sr). The cross section sigma(np .-->. NN.pi./sup +-/) was determined to be 1.92 +- 20 mb by integrating (d sigma/d.cap omega.*) over all angles. The partial cross section for pion production from T = 0 np interactions (sigma01) was found to be .1/sub -.1//sup +.5/ mb by using the relation sigma01 = 2sigma(np .-->. NN.pi./sup +- )--sigma(pp .-->. pp.pi.°). Stronger indications of nonresonant pion production were given by the presence of asymmetries between the positive and negative pion spectra and a comparison of the data with an isobar model calculation.

Triply differential cross sections for the reactions np --> np[pi]0 and np --> pp[pi]− have been measured at the WNR Facility of the Los Alamos Neutron Science Center at the Los Alamos National Laboratory. The measurements were made with a pulsed neutron beam with a continuous spectrum ranging from as low as a few MeV up to about 800 MeV, which covers the pion threshold energy of about 280 MeV and above, on a cryogenic liquid Hydrogen target. The two outgoing nucleons are detected in coincidence. Pure CsI crystals were used on one side of the beam (12,̊ 200,̊ 280)̊, whose pulse height information was used for energy determination of identified protons, and on the opposite side of the beam (12-̊ 32)̊, the neutrons or protons were observed in an array of organic scintillators with time of flight information. Measurement of'both nucleon energies, by the combination of the pulsed nature of the beam, times of flight and pulse height, completely determines the kinematics and allows the angular distribution of the unobserved pions to be extracted for both np --> np[pi]0 and np --> pp[pi]− actions.

Inclusive pion, kaon, proton, and antiproton production from proton-proton collisions is studied at a variety of proton energies. Various available parameterizations of Lorentz-invariant differential cross sections as a function of transverse momentum and rapidity are compared with experimental data. The Badhwar and Alper parameterizations are moderately satisfactory for charged pion production. The Badhwar parameterization provides the best fit for charged kaon production. For proton production, the Alper parameterization is best, and for antiproton production the Carey parameterization works best. However, no parameterization is able to fully account for all the data. Norbury, John W. and Blattnig, Steve R. Langley Research Center ANTIPROTONS; KAONS; PROTON ENERGY; SCATTERING CROSS SECTIONS; PIONS; PARAMETERIZATION; TRANSVERSE MOMENTUM