Neutron Star Formation: Quarks, Protons, Electrons Explained

[StanEvans]

So a programme that I watched on tv was talking about neutron stars and they said that the neutron stars neutrons were formed by protons and electrons combining to make neutrons. I was just wondering, how does this work, in the field of the quarks in the proton and how they are effected by an electron to change.

 

[mfb]

$e+u \to \nu_e + d$ via W exchange. The standard beta decay process, just with different initial particles.