# Charge anticharge superposition in nucleons

When a neutron converts itself into a proton, a negative quark changes into a positive quark. As the positive charge is geather than the negative ofcourse we must account for the expelled electron, it seems as there is a creation of charge and anticharge and maybe the nucleon quark charge is a resultant charge made up of distinct quantities of positive and negative charges in superposition. Are in that case quarks composite particles?

• Do you know about u with charge 2/3, d with charge -1/3, and the W- boson? n is udd, p is uud, and d goes to u and W-, which then goes to e ν. No quark needs be composite. What is it you are after? Apr 22 '20 at 21:08

Quarks come in "flavors" whose electric charges are one unit apart, but which are not equal in magnitude. The "up"-type quarks (called "up," "charm," and "top") have electric charge $$+2/3$$, while the down-type quarks ("down," "strange," "bottom") have electric charge $$-1/3$$. In a charged weak decay, a down-type quark changes into an up-type quark (or vice-versa); electric charge is conserved by emitting a charged lepton (an electron, a muon, or a tau) and a neutrino.
All of these particles have antimatter counterparts, whose electric charge is equal and opposite to the matter particle. So an anti-up quark has electric charge $$-2/3$$, and an anti-down quark has electric charge $$+1/3$$. Antiquarks are not involved in the beta decay of the matter neutron (well, not at "tree level").
There is a technical distinction between a particle that is a "superposition" and a particle that is "composite." There is currently no evidence that quarks are composite, with a substructure, in the way that atoms are composed of well-defined other particles. But there are several non-composite particles which can fairly be described as superpositions. Examples include the neutral $$K$$ mesons$$^\dagger$$; the neutrinos, whose flavor states don't have a well-defined mass and whose mass states don't have a well-defined flavor; and the photon, which is a mixture of two particles (which cannot be observed on their own) called $$W^0$$ and $$B$$.
$$^\dagger$$ Oops, the $$K$$ mesons are composite, since they're made of quarks. But if you want to read more about what a superposition means, the literature on $$K$$ mesons is a good place to start.