Beta (\(\beta^-\)) decay is the release of an electron by the change of a neutron to a proton. The neutron (charge = 0) is made up of one up quark (charge = \(\frac{2}{3}\)) and two down quarks ...

Here is the equation for the alpha decay of radon-219 into polonium. Beta decay involves the conversion of a down quark to an up quark. This changes a neutron into a proton plus an electron.