A Experimental Limit on Proton Decay: Proton ---> Positron + Neutral Pion
Abstract
A search for the decay p (--->) e('+) (pi)('0) was performed in the 8000 metric ton Irvine-Michigan-Brookhaven water Cherenkov detector which was constructed underground at a depth of 1570 meters of water equivalent. In a 130 live day exposure (3.9 x 10('32) proton years in the 3300 ton fiducial volume of the detector) no events consistent with the above decay were found. With calculated detection efficiencies of 0.92 and 0.54 for p (--->) e('+) (pi)('0) events occurring in hydrogen and oxygen respectively, this thesis establishes at the 90% confidence level that the partial lifetime for this decay mode exceeds 1.1 x 10('32) years. This result is incompatible with predictions from minimal SU(5), the simplest of the Grand Unified Theories and with previously reported experimental measurements. For p (--->) e('+) (pi)('0) decays occurring from free protons in the hydrogen in our detector we establish a partial lifetime limit which is independent of nuclear effects of 3.1 x 10('31) years. The rate and characteristics of neutrino interactions observed in our detector (112 events in 130 days) are compatible with expectations. This thesis documents the author's design for the electronics readout system for the IMB detector as well as his event fitting, reconstruction, and event simulation software.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- 1983
- Bibcode:
- 1983PhDT........48F
- Keywords:
-
- PIZERO;
- WATER;
- CHERENKOV;
- Physics: Elementary Particles and High Energy