Analysis of 303 GeV/c proton-nucleus interactions tagged by high-energy γ-rays with emulsion chambers

Two emulsion chambers are exposed to 303 GeV/c proton beams at the Fermi National Accelerator Laboratory. The event structure of 70 proton-nucleus interactions tagged by high-energy γ-rays is analysed. Strong correlation is observed in the forward fragmentation region between high-energy γ-rays and a charged secondary particle with the highest transverse momentum (PT ≳ 1 GeV/c) in each event. Formation of a forward excited baryon and its decay into a charged baryon and γ-rays is one of the possible explanations of this effect. Correlation between the excited baryon and other produced particles in each interaction is also studied.