As known, the proton is from two up and a single down quark, while the neutron is from a single up and two down quarks. The down quark is a little bit more massive and the up, and so the neutron is also a little bit more massive as the proton. It was my naive layman's hypothese.

But the masses of the quarks (4 and 8 MeV) take only a tiny part in the whole mass of the baryons ($\approx 1\textrm{ GeV}$). Their masses are coming mainly from the gluon field around them.

And, considering the relative recent charming result of the calculation of the protons and neutrons from the principles, I think maybe this question could have a more detailed answer.

I think the mass difference is coming from the difference of the gluon field, is it okay? What is that difference?

Extension: comment says, that calculation couldn't yet differentiate between protons and neutrons. I hope, maybe the last 8 years made possible this improvement.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.