Highlights from the ARGO-YBJ Experiment

The ARGO-YBJ experiment is an air]shower detector installed at high altitude (4300 m a.s.l.) at the Yangbajing Cosmic Ray Laboratory (Tibet, China). The detector is a full-coverage single layer of Resistive Plate Chambers (RPCs) operated in streamer mode, providing a single-hit time resolution less than 2 us. The detector structure allows unprecedented imaging of the shower front (e.g. space-time distribution and thickness). The installation of the detector was completed in October 2007 and the experiment has been running uninterruptedly since then, collecting over 2 x 10(11) events generated by cosmic rays and gamma rays with lower energy threshold of a few hundreds of GeV, over a similar to 2 sr solid angle. The main research topics of the ARGO-YBJ experiment are the search for astronomical gamma-ray sources and cosmic-ray physics in the energy range from a few hundreds of GeV up to above 1 PeV. The main results obtained so far are presented, emphasizing the study of the TeV emission from the Crab Nebula and the Mrk 421 AGN, the search for antimatter in the primary cosmic radiation and the search for gamma-ray bursts with a ground-based detector.