33RD INTERNATIONAL COSMIC RAY CONFERENCE, RIO DE JANEIRO 2013 THE ASTROPARTICLE PHYSICS CONFERENCE Study of the time structure of EAS particles with ARGO-YBJ

Abstract: The ARGO-YBJ experiment is an Extensive Air Shower array located at the high altitude Yangbajing Cosmic Ray Laboratory in the Tibet region. The detector consists of a layer of Resistive Plate Counters (RPCs) covering a total area of about 11000 m2. Detector features allow studying the shower front structure with unprecedented space-time resolution. Besides the study of the shape of the shower front, events with peculiar particle time distribution can be selected and analyzed. Two main categories have been identified: Multiple-Front and Wide-Front Showers (MFS and WFS). MFS events might be produced by exotic particle decay, while WFSs are expected to be due to EAS with the core position well outside the detector carpet. Preliminary results of these analyses, also in terms of the Linsley parametrization of the shower thickness, will be presented