# How are exchange terms in phenomenological nuclear potentials related to the exchange of nuclear force carrirer particles?

Consider a proton-neutron system.

Phenomenlogical nucleon-nucleon potentials contain exchange forces terms (Majorana, Bartlett and Heisenberg terms), which are linked to the symmetry of the state w.r.t. (for example) the exchange of isospin (i.e. charge).

On the other hand proton and neutron can interact exchanging a pion (in the Yukawa theory) and exchange their charges: if proton and neutron collide they can exchange their charges because of the exchange of a charged pion. In this sense the interaction between neutron and proton (nuclear force) can be defined as an exchange force (because of the exchange of the pion, as described here).

I'm quite confused about the term "exchange", in particular in the first case: what is "exchanged" when we talk about exchange force in the case of nuclear force? Is the exchange related to the symmetry of the system (as in first case) or to the physical exchange of a particle (Yukawa meson)?

• Can you link to some papers that use the potentials you're thinking about? I think I have an answer for you but I don't want us to talk past each other. – rob Jul 2 '18 at 1:17
• @rob I found a description on Basic "Physics Of Radiotracers: Volume II" page 8 (visible on google books) – Sørën Jul 2 '18 at 8:56
• Do you mean here? – rob Jul 3 '18 at 16:06