Particle production at high baryon density in central Au+Au reactions at 11.6A GeV/c

Semi-inclusive proton and pion distributions from central Au+Au reactions at 11.6A GeV/c have been measured. The proton rapidity distribution shows significantly increased stopping compared to lighter systems, providing strong evidence for the formation of a state of matter with baryon density substantially greater than normal nuclear matter. Unlike reactions at this energy induced by lighter heavy ions, at low m{sub t}-m{sub 0} the proton invariant spectra deviate from a single exponential shape and become flatter, while {pi}{sup {minus}} spectra are found to rise faster than the {pi}{sup +} spectra. {copyright} {ital 1998} {ital The American Physical Society}