nalysis of IceCube Data During the Three Year Period Beginning May 2006 P. B. Price, Physics Dept., U. C. Berkeley
The Berkeley group led by P. B. Price has participated in the AMANDA high-energy neutrino astrophysics project since its inception in 1991. Beyond their participation in the construction of the growing IceCube observatory, this new grant will provide some support to the present group of 12 researchers as they analyze data flowing from IceCube. Here are a few of the topics they will study: - Development of algorithms for analysis of electromagnetic cascades induced by electron neutrinos. They will be used to study high-energy cascades of both atmospheric and astrophysical origin. - Using their new reconstruction algorithms, they will look for neutrinos produced by giant flares from powerful extragalactic sources of high energy neutrinos. - They will exploit their method for increasing signal to noise by "stacking" data from particular families of point sources of high energy neutrinos with the expectation of seeing neutrinos from certain classes of active galaxies. - By means of a special "slow-particle trigger", they will search for hypothetical particles such as strangelets, supermassive magnetic monopoles, and Q-balls that will pass through much of the earth without significant slowing and that can be recognized by their slow speed (less than 1% the speed of light). - Theorists have recently calculated that neutrinos with energy up to a trillion electron volts generated in core-collapse extragalactic supernovae may be detectable in IceCube for sources at distances within about 50 million light years of Earth. An unmistakable signal would be the detection of at least two such neutrinos from the same direction in the sky within a few seconds. Such a discovery would have great significance for astrophysics, gravitational physics, and relativity. The Berkeley group has led in inventing new devices for AMANDA and IceCube and in applying them to totally different topics at the forefront of science. The first such device was their laser-powered dust logger, which they have used to detect volcanic ash layers and climate-correlated dust concentrations, by means of which they discovered a causal relationship between large volcanic eruptions and abrupt climate change. By adding fluorescence channels to the dust logger, they created a biologger, with which they can detect various classes of microbes that contain molecules such as chlorophyll and tryptophan (an amino acid in all cells) whose fluorescence induced by the biologger allows them to study the history of microbial deposition and its possible correlation with climate and volcanism. A very recent example of the breadth of their interest is their realization that the explanation of the mysterious increase in phototube noise near the bottom of the IceCube strings is the light emitted by the glacial ice at great depths where the temperature is warm enough to allow shear of the flowing ice to develop, during which visible light and sound are produced. This poorly understood optical phenomenon of triboluminescence induced during jerky deformation of certain solids such as ice will be studied using IceCube data. There will no doubt be new spinoffs as they analyze ongoing IceCube data.
