Prof Roman Walczak

Abstract:

The cross section for the process e⁺e^-→π⁰+ anything has been measured at an average center of mass energy of 34.6 GeV for π⁰ energies between 0.7 and 17 GeV. The angular distribution for π⁰ energies larger than 2 GeV is of the form dσ/dΩ∼1+Acos²θ, with A=1.2±0.5. The ratio of π⁰ to π^± production in the measured energy range is 2σ(π⁰)/(σ(π⁺)+σ(π^-))=1.13±0.18 The form of the differential cross sections agrees within the errors. The mean π⁰ multiplicity is 5.8±0.9. © 1986 Springer-Verlag.

Abstract:

An analysis of the production of KS⁰KS⁰ and K^±Ks⁰π^∓ by two quasi-real photons is presented. The cross section for γγ→K⁰ {Mathematical expression}, which is given for the γγ invariant mass range from K {Mathematical expression} threshold to 2.5 GeV, is dominated by the f′(1525) resonance and an enhancement near the K {Mathematical expression} threshold. Upper limits on the product of the two-photon width times the branching ratio into K {Mathematical expression} pairs are given for Θ(1700), h(2030), and ξ(2220). For exclusive two-photon production of K^±Ks⁰π^∓ no significant signal was observed. Upper limits are given on the cross section of γγ→K⁺ {Mathematical expression}π^- or K^-K⁰π⁺ between 1.4 and 3.2 GeV and on the product of the γγ width times the branching ratio into the K {Mathematical expression}π final states for the ηc(2980) and the ι(1440), yielding Γ(γγ)→i(1440))·BR(i(1440)→K {Mathematical expression}π<2.2 keV at 95% C.L. © 1985 Springer-Verlag.