Effect of nuclear transparency from the (p,2p) measurements on 6Li and 12C at 1 GeV

We studied the production of protons to the backward direction in (p,2p) reactions on 6Li and 12C, accompanied by a proton emitted into the forward hemisphere. The momenta of the final two protons were measured in a wide range with the two-arm time-of-flight spectrometer. For each event we reconstructed the mass of the intermediate off-shell particles. We have discovered a strong narrow dip in the mass spectra of intermediate mesons at the mass of the real pion.