Speaker
Dr
Mauricio Bustamante
(Center for Cosmology and Astroparticle Physics, The Ohio State University)
Description
Cosmogenic neutrinos, produced in interactions of ultra-high-energy cosmic rays (UHECRs) with cosmological background photons, should exist above 100 PeV, but remain undetected. Their flux depends on the uncertain composition and maximum energy of UHECRs. Pessimistic predictions, of 10^{-10} GeV cm^{-2} s^{-1} sr^{-1} or lower, are beyond reach of existing detectors after reasonable exposure times. The planned Giant Radio Array for Neutrino Detection (GRAND) addresses this possibility: its main goal is the assured discovery of cosmogenic neutrinos, even in pessimistic flux scenarios. It will detect the coherent radio emission from extensive air showers triggered by the decay of taus produced in interactions of cosmogenic nu_tau's in rock. By densely instrumenting a very large area --200 000 km^2 with 10^5 small radio antennas-- GRAND could reach an exquisite sensitivity of 3*10^{-11} GeV cm^{-2} s^{-1} sr^{-1} above 30 PeV in 3 years, corresponding to a handful of events per year. More reasonable flux scenarios predict up to 100 events per year. A precise angular resolution of 0.1° will allow to test isotropy and source correlations. I will discuss these and other science goals of GRAND, the status of the prototype array, and future prospects.
Author
Dr
Mauricio Bustamante
(Center for Cosmology and Astroparticle Physics, The Ohio State University)
