Beta Decay and Positron Emission
In reading about radioactive decay, if these equations
Beta decay: Neutron =>proton + electron + neutrino
Positron emission: Proton => positron + neutron + neutrino
A product of the decay of a neutron (the proton) can, during
positron emission, decay to form a neutron.
How can a proton decay to form a neutron in positron emission if, as
indicated by beta decay, it is a part of a neutron?
A proton is not part of a neutron. A neutron is not part of a proton.
They are very similar particles. According to quantum theory, each is
made of three particles called quarks. One of these three quarks is
different for protons as compared to neutrons. A neutron has just a
little bit more mass than a proton.
Given enough energy, each can change into the other. To maintain the
balance of the universe, the other particles must be emitted during the
change. The electron or positron maintains the balance of electric
charge. An anti-neutrino is emitted with the electron. A neutrino is
emitted with the positron (i.e. anti-electron). This maintains the
balance of leptons. Without such balances, the universe could easily
get out of control.
Dr. Ken Mellendorf
Illinois Central College
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Update: June 2012