This page is just a collection of some old and new things I have done and want to make available for others in the collaboration. Lots of technical stuff.
This is an analysis to search for a WIMP signal from the centre of the Earth, or (most probably) to set an upper limit for the flux of neutrinos from WIMP annihilation that can be arriving at the detector from this direction. The analysis is optimized using the 20% data sample from 2001-2003, and the following concerns only the preparations for this specific analysis.
The data filter does not use hard angular cuts, because we wanted it to be useful also for other types of analyses. The first precut before optimization of the Earth WIMP analysis is therefore to select only events with reconstructed zenith angle larger than 140 degrees. After this, the events are retriggered (only events that still fulfill at least one of the trigger conditions after hit cleaning are used).
The detector was slightly different in these three years. Most of the difference happened between 2001 and 2002, when the trigger settings were changed and parts of the detector electronics was repaired and exchanged. The following figure shows an example of the kind of difference we see in the data from these years.
After retriggering the cuts are optimized to reduce the background while keeping as much as possible of the signal. The optimization is made following a method used for a similar analysis (thesis by P Olbrechts as gzipped postscript file) with good results.
Details on the method, selected variables and results are located on the unblinding page, available for those who know the secret password.