"Results of Neutrino Analysis performed using TeraGrid"
UC Irvine: Andrea Silvestri
I have been using Datastar to perform numerical simulations of self-gravitating accretion disks, in particular disk around young stars. My most recent work has been to consider under what conditions such disks may fragment to form bound, gaseous objects. In disks around young stars, such a process could form Jupiter-like planets. A similar process could lead to the formation of stars in disks in the nuclei of active galaxies.
A new data acquisition electronics of the AMANDA-II detector was upgraded in 2003 to readout the complete waveforms of the optical sensors using Transient Waveform Recorders (TWR). The new system produces 15TB (after compression) per year compared to ~1TB of the standard system. Using the storage capacity of the SRB system and the high performance computing resource of the TeraGrid cluster, we performed the analisys of 15 TB of raw data in a reasonable short time scale.
The goal of this analysis is to search for atmospheric neutrinos using the data with waveforms and to compare the results to the standard data analysis. From the analysis based on waveform data, 1152 neutrinos are observed compared to 1080 and 1179 neutrinos of the standard analyses.
The figure shows the cos(theta) angular distribution of the atmospheric neutrinos sample extracted from the data with waveforms, compared to the standard analyses. Satisfactory agreement can be seen for the cos(theta) distribution of the neutrino samples obtained by the different analyses.
This encouraging result was obtained by first converting the waveforms into the more restricted information collected by the old acquisition system. Now that the performance of the TWR-DAQ is verified by the atmospheric neutrino analysis, we are developing new software tools to exploit the full information contained in the waveform. We expect that the additional information contained in the waveform will improve energy and angular resolution crucial for the search of high energy phenomena.
The full data analysis was performed using the TeraGrid and the SRB systems with approximately 60,000 SU hours.
Reference: A. Silvestri et al., Performance of AMANDA-II using Transient Waveform Recorders, Proceedings of 29th International Cosmic Ray Conference, Pune, India August 3-10 2005.
