Measurement of Cosmic Ray spectrum and Anisotropy with ARGO-YBJ

In this paper we report on the observation of the anisotropy of cosmic ray arrival direction at different angular scales with ARGO-YBJ. Evidence of new few-degree excesses throughout the sky region 195$^{\circ}\leq$ R.A. $\leq$ 315$^{\circ}$ is presented for the first time. We report also on the measurement of the light-component (p+He) spectrum of primary cosmic rays in the range 5 - 200 TeV.Comment: Invited talk to the 3rd Galileo - Xu Guangqi meeting, October 11-15, 2011 Beijing (China

The Trigger System of the ARGO-YBJ detector

The ARGO-YBJ experiment has been designed to detect air shower events over a large size scale and with an energy threshold of a few hundreds GeV. The building blocks of the ARGO-YBJ detector are single-gap Resistive Plate Counters (RPCs). The trigger logic selects the events on the basis of their hit multiplicity. Inclusive triggers as well as dedicated triggers for specific physics channels or calibration purposes have been developed. This paper describes the architecture and the main features of the trigger system.Comment: 4 pages, to be published in the Proceedings of the 28th International Cosmic Ray Conference (Tsukuba, Japan 2003

Latest results on cosmic ray physics from the ARGO-YBJ experiment

Cosmic ray physics in the 10^12–10^15 eV primary energy range is among the main scientific goals of the ARGO-YBJ experiment. The detector, located in the Cosmic Ray Observatory of Yangbajing (Tibet, China) at 4300 m a.s.l., is a full coverage extensive air shower array consisting of a carpet of Resistive Plate Chambers (RPCs) distributed over an area of more than 10 000 m2. The apparatus layout, performance and location offer a unique opportunity for a detailed study of several characteristics of the hadronic component of the cosmic ray flux in an energy window marked by the transition from direct to indirect measurements. Moreover, the analog readout of the RPC signals indeed provides a powerful tool to study, with unprecedented resolution and without saturation, the extensive air shower space–time structure down to few meters from its axis. Latest results concerning the study of cosmic ray energy spectrum, mass composition and arrival directions will be given together with the search for an antiproton signal, the proton–air cross-section measurement, the study of the interplanetary magnetic field, and the effects of the geomagnetic field on secondary particles. Furthermore, particle distributions close to the shower axis are being extensively studied, also giving new inputs, in the very forward region, to the hadronic interaction models currently used for understanding particle physics and cosmic rays up to the highest energies

Time structure of the extensive air shower front with theARGO-YBJ experiment

The ARGO-YBJ experiment is an Extensive Air Shower array currently operating at the high altitude Yangbajing Cosmic Ray Laboratory (Tibet, P.R. China 4300 m a.s.l.). The detector consists of a layer of Resistive Plate Counters (RPCs) covering an area of about 5800 m2. Its fine granularity, full coverage design and high time resolution provide a detailed characterization of cosmic ray showers. Curvature, thickness and shape of the shower front have been investigated up to 100 TeV. Detailed Monte Carlo simulations of the detector response have been performed using CORSIKA showers and results are compared to data. Finally, correlations of measured observables with the nature of the primary are discusse