We have measured dijet angular distributions at √s =1.8 TeV with the Collider Detector at Fermilab and the Tevatron p¯p Collider and find agreement with leading-order QCD. By comparing the distribution for the highest dijet invariant masses with the prediction of a model of quark compositeness, we set a lower limit on the associated scale parameter Λc at 330 GeV (95% C.L.).
We have used a magnetic spectrometer to study the production of charged pions in collisions of 600-MeV neutrons with nuclei of Be, C, Al, Cu, and Pb over a wide range of angles. For these nuclei we have obtained at five angles (16, 30, 60, 90, and 123°) the spectra of pions of both signs, on the basis of which we have found the cross sections, atomic-number dependences, and angular distributions of pion production. The influence of a number of effects on the characteristics of pion production in nuclei is discussed. The analysis performed permits us to obtain a qualitative picture of the basic regulari- ties of pion production.
The transverse momentum distribution at 90° of pions, protons and antiprotons have been measured at the CERN intersecting storage rings for C.M. energies between 23.2 and 52.7 GeV. In this energy range, the pion and proton distributions are almost energy independent. The antiproton production rises by a factor of two between 23.2 and 52.7 GeV.
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Experimental data exhibiting the separation of single and double quasi-elastic scattering in proton-deuteron collisions at 19.2 GeV/ c and for momentum transfers around 1 GeV/ c are presented. An analysis of the scattering cross section in terms of the multiple scattering theory is given. The possibilities for the deduction of proton-neutron differential cross sections particularly at large momentum transfers are pointed out.
Inclusive π − spectra have been measured for 14 N+C collisions at 41 A , 67 A , 80 A and 135 A MeV, the lowest energies measured for the charged pion. The cross sections fall exponentially with T π and the exponential slope factors at 90° in the nucleon-nucleon center of mass frame are determined. Energy distributions below a beam energy of 100 A MeV are less steep than expected from the monotonic decrease of the slope factor down to 100 A MeV. The production mechanism of energetic pions far below threshold is discussed for several models.
The experimental data on d-d collisions at 4.3, 6.3 and 8.9 GeV/ c , exhibiting the two-peak structure in the high-momentum parts of the secondary deuteron spectra at momentum transfers | t | ≈ 0.4–0.8 (GeV/ c ) 2 , are presented. An analysis of the results in terms of the multiple nucleon-nucleon scattering model is given. Some conclusions about the mechanism of the elastic and quasielastic d-d scattering at the above-mentioned momentum transfers are made.
Differential and double differential cross sections of positive pion production by 240 MeV protons on carbon and copper nuclei are measured. The energy dependence of differential cross section for copper nucleus at 90 deg angle within the 240-500 MeV energy range of protons and angular dependence of the integrated differential cross section are obtained. It is shown that the differential cross section at 250 MeV is 80 times less than that at 585 MeV