Beta Decay
Radioactivity is the spontaneous emission of radiation (energy) by certain unstable atomic nucleus. This phenomenon, discovered by Henri Becquerel
and Pierre & Marie Curie in 1896-1898, occurs in different forms. Let's focus on the beta decay, discovered a few years later by Ernest Rutherford.
More specifically, there are two beta decays: beta minus and beta plus.
Both are described in more detail within the following picture gallery (Here: Help to understand Feynman diagrams):
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During beta minus decay, an electron is emitted from an unstable nucleus. This happens when a neutron
changes into a proton. There is also one electron anti-neutrino produced. The electron and
electron anti-neutrino come from the decay of the W-particle (here the W--particle).
Particle physicists see this decay like this: when one down quark of the proton transforms into an up quark,
a W--particle is emitted. The W--particle decays into an electron and an electron
anti-neutrino after the unbelievably short time of about 10-25 seconds.
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During beta plus decay, a positron is emitted from an unstable nucleus when a proton inside the nucleus transforms into a neutron.
An electron neutrino is also produced. The positron and electron
neutrino come from the decay of the W-particle (here the W+-particle).
Particle physicists see the decay like this: when one up quark of the proton transforms into a down quark,
a W+-particle is emitted. The W+-particle decays into a positron and an electron
neutrino after the unbelievably short time of about 10-25 seconds.
Conservation of Electric Charge
Have you noticed that the sum of electric charge remains the same during the beta decays? Just
calculate the electric charge before and after the decay of the existing particle.
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