Search for electron decay mode e→γ+ν with prototype of Borexino detector

The prototype of the Borexino detector Counting Test Facility, located in the Gran-Sasso laboratory, has been used to obtain a bound on the stability of the electron. The new lower limit on the mean lifetime defined on 32.1 days of data set is tau(e(-) --> nu(e) + y) greater than or equal to 4.6 x 10(26) yr (90% c.l.). (C) 2002 Published by Elsevier Science B.V.