Why is it difficult to detect the presence of an anti-neutrino during decay ? Define the term decay constant of a radioactive nucleus and derive the expression for its mean life in terms of the decay constant.
Since penetrating power is high during decay, that's the reason for the difficulty in detecting the presence of anti-neutrino.
It also doesn't interact with matter.
The decay constant of a radioactive nucleus is defined as the reciprocal of the time duration in which undecayed radioactive nuclei reduce to times the nuclei present initially.
In terms of the decay constant, the expression for the mean life.