Heavy Pair Production Research Articles

Shrinkage, complex poles and the Chou-Yang model

The shrinkage of the diffraction peaks is reproduced by the interference of a geometric pomeron and of complex poles representing S-channel threshold effects (like heavy pair production). Asymptotically, one recovers the Chou and Yang model. The shrinkage is expected to stop at P lab ⋍ 10 5 GeV/c . The total cross section σ T is conjectured to have a maximum of 45–48 mb (for pp) at about the same energy where the shrinkage stops. The asymptotic value of σ T would only differ from the maximum value by about 1 mb. The break structure at |t| ⋍ 1.2 GeV 2/c 2 seen at low energies for pp elastic scattering is explained in term of secondary Regge exchanges only. At high energies, the dip at | t| ∼ 1.3–1.4 GeV 2/ c 2 is given by the geometric pomeron. Because of the eikonalization procedure one obtains an intermediate | t| shrinkage and a dip displacement in good agreement with experiment.

Thermodynamic inclusive single particle spectra and particle production ratios at the ISR

Two essential modifications of the thermodynamic single particle spectra using fireballs according to the strong bootstrap model are described: (i) An energy-dependent velocity weight function is introduced which leads to better agreement with the flat single particle spectra in the central region observed at the ISR. (ii) Heavy pair production is modified by producing the two particles in different steps of the decay chain of the fireballs. The fact that heavy fireballs are produced leads in the model to a natural understanding of the deviations from scaling behaviour in the central region of single particle spectra p + p → π +-, p or K − + anything between 20 GeV and ISR energies. The particle production ratios p /π −, K −/π −, π +/p, K +/p and p /p are compared to recent ISR data.