Studies on the reaction γp → π+π-p at the experiment WA69 in the energy range from 60 to 170 GeV

In the present thesis the reaction γp → π+π-p was studied. The ρ(770) was analyzed by means of events in which the detectors and the reconstruction programs have detected the recoil proton. The cross section of the ρ production process was determined. The values for the cross section ρ (p → ρ(770)p) lie typically at (5.3(+1.6-0.5) μb. The extrapolation of the differential cross section dσ/dt to t=0 yields at a slope parameter b of (6.9±1) GeV2 a value of 65±20) μb/GeV2 a value of (65±20) μb/GeV2 and a cross section of σ(γp → ρ(770)p) (9.3±3) μb. The decay angular conservation. The spin-density matrix elements ρ1,-1 and Re(ρ1,0) are in the mass range of the ρ in the framework of the measuring accuracy equal to zero, the ρ0,0 lies with a value of 0.09±0.02 a little above. The reaction γ p → Φp studied with the same data on the decay into 2 kaons was measured with a cross section σ(γ p → Φ(→ K+K-)p) of (107(+35-12) nb. In the mass range of the ρ(1600) both in the data with reconstructed proton and in the data where only the 2 pions were to be detected a significant signal is to see. (orig./HSI)