Lower limit on the proton lifetime according to data from the Baksan underground scintillation telescope
Alekseev E. N., Bakatanov V. N., Butkevich A. V., Voevodskii A. V., Gitel'son A. A., Danshin A. E., Keidan G. P., Kiryushin A. A., Petkova O. I., Chudakov A. E., Shtern B. E.
Two inner layers of scintillators of the Baksan underground telescope are used to study proton decay, while six outer layers serve as an anticoincidence shield. No signal with an energy > 500 MeV was observed over an exposure time of 0.47' yr. On this basis a lower limit of 1.25 Χ 1030 yr is estimated for the lifetime of the proton for the neutron).