# Hi,When a nucleus does $\beta$-decay$$_Z^A X 1. Jan 10, 2012 ### A_B Hi, When a nucleus does $\beta$-decay [tex] _Z^A X \rightarrow _{Z+1}^A Y + e^- + \overline{\nu}$$
The daughter nucleus has one more charge than the mother nucleus, so it will take an electron into its cloud. Why is this electron's contribution to the Q-value said to cancel that from the emitted $\beta$ particle? The $\beta$ particle is created in the reaction so that obviously gives a $-m_e c^2$ in the Q-value. But the absorbed electron exists before and after the reaction, so I don't see how it should have any effect.

thanks
A_B