Speaker: Pravata Kumar Mohanty, Tata Institute of Fundamental Research, Mumbai
Abstract: The GRAPES-3 experiment located in Ooty, India employs a dense array of plastic scintillator detectors and a large area muon detector to measure all charged particles and muonic components in cosmic ray showers, respectively. Recently, we reported the measurement of the proton spectrum of cosmic rays from 50 TeV 1.3 PeV, with a significant hardening observed at around 166 TeV. The new feature contradicts the long-held belief that the cosmic ray spectrum follows a single power-law up to the knee energy and may require more complex models such as those where classes of sources with different cutoffs contribute to the flux. Additionally, we have reported the observation of two significant small-scale anisotropic structures in the cosmic ray arrival distribution, consistent with the observations of HAWC and ARGO-YBJ experiment. In this talk, I will provide an overview of the GRAPES-3 experimental setup, discuss the above mentioned results, and tell about the ongoing upgrade activities and future plans.