Beta Decay not a specific problem, just a question

[erinec]

I understand that a beta plus decay emits positron and beta minus decay emits electron. For the calculation of kinetic energy of the particle released, you take into account the mass of electron for beta plus, but why is it that you DON'T take into account the mass of electron for beta minus? I kind of heard that the mass of electron cancels out for beta minus decay. I do not see how that happens. If you could show me how the mass of electron "cancels out" when calculating the kinetic energy released for beta minus decay, I would feel extremely grateful. Thank you for taking your time to read my question.

 

[Hootenanny]

I understand that a beta plus decay emits positron and beta minus decay emits electron. For the calculation of kinetic energy of the particle released, you take into account the mass of electron for beta plus, but why is it that you DON'T take into account the mass of electron for beta minus? I kind of heard that the mass of electron cancels out for beta minus decay. I do not see how that happens. If you could show me how the mass of electron "cancels out" when calculating the kinetic energy released for beta minus decay, I would feel extremely grateful. Thank you for taking your time to read my question.

Who doesn't take into account the mass of the electron?

 

[nlightner]

Hello,

Thank you for your question about beta decay. You are correct in understanding that beta plus decay emits a positron and beta minus decay emits an electron. The calculation of kinetic energy released in beta decay involves the difference in mass between the parent nucleus and the daughter nucleus. This is known as the mass defect. In beta plus decay, the mass defect is equal to the mass of the electron, which is why we take it into account when calculating the kinetic energy released. However, in beta minus decay, the mass defect is not equal to the mass of the electron. Instead, it is equal to the mass of the electron plus the mass of the antineutrino. The mass of the antineutrino is very small compared to the mass of the electron, so it is often neglected in calculations. This is why we do not take the mass of the electron into account when calculating the kinetic energy released in beta minus decay. It does not cancel out, but rather is a very small contribution to the overall mass defect. I hope this helps clarify your understanding. Thank you for your interest in this topic. If you have any further questions, please do not hesitate to ask.