Professor Brian Foster OBE, FRS

Abstract:

We have studied the properties of hadron production in photon-photon scattering with tagged photons at the e+e- storage ring PETRA. A tail in the pT distribution of particles consistent with pT-4 has been observed. We show that this tail cannot be due to the hadronic part of the photon. Selected events with high pT particles are found to be consistent with a two-jet structure as expected from a point-like coupling of the photons to quarks. The lowest-order cross section predicted for γγ → qq, σ = 3 Σ eq4 · σγγ → μμ, is approached from above by the data at large transverse momenta. © 1981.

Abstract:

We report on the results of a partial-wave analysis of the 3π system produced by baryon exchange in the reaction K-p→Σ-π+π+π- at 4.2 GeV/c. We confirm the existence of an enhancement in the 1+S(ρ{variant}π) wave as previously established from a Dalitz plot analysis of the same data. The phase variation of this wave is found to be consistent with that expected for a resonance and thus the enhancement is identified with A1 production. No clear signal for this state is found in either the reaction K-p→Σ+π+π+π-π- or K-p→Λπ+π-π0. We also find production via baryon exchange of the A2 in all three reactions and the ω and ω* (1975) in the third reaction. © 1981.