Ringlike event observed in superhigh-energy interactions and a possible phase transition

The kinematical analysis of a ringlike event observed in a mountain emulsion chamber shows that this kind of event might be related to multiparticle production within a narrow rapidity interval of the fragmentation region in superhigh-energy interactions, therefore possibly related to a phase transition in the nucleus-nucleus interaction. The air cascade showers induced by superhigh-energy nucleus-nucleus interactions are simulated by a transition model. Under the conditions of the emulsion chamber experiment, the ringlike event is obtained.