Experimental Test of Baryon Conservation and Neutrino Flux Limits

An experiment has been performed in which events not directly attributable to cosmic rays or natural radioactivity were observed for 4500 h in a 200-liter liquid scintillation detector. Shielding from cosmic rays was obtained through anticoincidence techniques and by locating the detector 585 m underground. Background from natural radioactivity was reduced by placing high-energy requirements on acceptable events. The residual signal has been used to establish new lower limits on the stability of nucleons and a new upper limit on the product of the cross section and the electron neutrino (νₑ, νₑ) flux whatever its origin, providing its energy is 400 MeV and >30 MeV (νₑ) or > 12 MeV (νₑ). Depending on the assumed decay modes, nucleon lifetime limits in the range 0.6×{}10²⁸ to 4×{}10²⁸ years were obtained. The upper limits on the neutrino cross-section flux products are 8.5×10^-38νₑ sec^-1 and 3.2×10^-38νₑ sec^-1.