The real part of the forward amplitude for Compton scattering on protons was measured through the interference between the Compton and Bethe-Heithler amplitudes by detecting the zero-degree electron pairs asymmetrically. The measurement was made at an average photon energy of 〈k〉=2.2 GeV, and an average momentum transfer to the recoil proton 〈t〉=−0.027 (GeV/c)2. The result confirms the prediction of the Kramers-Kronig relation.
No description provided.
The reaction π − p → ηφ has been studied at 1.8 GeV/ c incident pion momentum using the Bologna-CERN NBC set-up, in order to investigate the electromagnetic decay mode φ → ηγ . We observed (27 ± 6) events, yielding a branching ratio Γ(φ → ηγ) Γ(φ → total ) = (7.3 ± 1.9)% . The theoretical implications of this result are discussed.
ASSUMING THE TOTAL PHI CROSS SECTION IS 35 +- 5 MUB, THIS YIELDS THE BRANCHING RATIO OF (7.3 +- 1.9) PCT FOR PHI --> ETA GAMMA.