Possible consequences of the zeno effect on nuclear double-beta decay and a bound on m_ν

It is shown that a Zeno-type effect due to disturbances caused by collisions associated with correlated pairs inside the nucleus may significantly modify double-beta decay rates. Several nuclei for which double-beta decay data is available are studied, and it is shown that the trend of the effect is consistent with this interpretation. The resulting ratio of the lifetimes of ¹²⁸Te to ¹³⁰Te could indicate (in the absence of particle-particle interaction corrections to which the theoretical amplitudes are extremely sensitive) an increased likelihood for the occurrence of the 0ν mode. An upper limit on the neutrino mass of about 4 eV appears to be compatible with the experimental bounds on ⁷⁶Ge, ⁸²Se double-beta decay lifetimes, and the ratio of the lifetimes of the Te isotopes.