hey, i was told that in a Atom's Nucleus, Nucleons keep changing from Proton state to Neutron state , and vice versa , by the means of Pions exchange. But how does this works I know : p+ : u u d n : u d d Positive pion (that turns neutron into proton ?) : (d) u u d d + (d) u = u u d ?? Negative pion (that turns proton into neutron ?) : (u) d u u d + (u) d = u d d ?? /// Also : how can a Baryon produce a pion to be able to exchange it ?? i mean how does it produce the anti quark ?