ACP Seminar (Astronomy - Cosmology - Particle Physics)

Speaker: Olaf Scholten (KVI / Groningen)
Title: Improved flux limits for neutrinos with energies above 10^22 eV from NuMoon observations
Date (JST): Mon, Feb 22, 2010, 15:00 - 16:00
Place: Seminar Room at IPMU Kamioka Satellite
Abstract: The origin of cosmic rays at the highest energies is still unknown, all we know that they must be ejected from an extremely energetic cosmic event. The quest in high-energy cosmic-ray physics is to find the flux at the highest energies as well as the sites where they originate from.

Ultra-high energy (>10^20 eV) cosmic rays have a flux of about 1 particle per square kilometer per year, making it necessary to work with large detectors. When such a particle hits the Moon a very strong electromagnetic pulse is generated through a process known as the Askaryan effect. This mechanism will be explained and it is argued that in an observing window around 150~MHz there is a maximum chance for detecting this radiation on Earth with radio telescopes commonly used in astronomy. Using this principle we have set a new limit on the flux of neutrinos with energies in excess of 4 x 10^22 eV in 50 hours of observation time with the Westerbork Synthesis Radio Telescope array. Future plans for observations with LOFAR and SKA will also be discussed.
Contact: Kai Martens
Remarks: you can participate in this seminar in seminar room D on 5th floor.