As far as I know a Baryon is made of three Quarks (eg uud, udd etc) and a Meson of two Quarks, a Quark/Antiquark pair. As I am not a student / scholar in Physics but very deeply interested in this field, I couldn't find any explanation, why a Meson is omly made up by a Quark/Antiquark pair. What hinders a Meson to be made of, let's say an up-down Quark pair? Pauli only forbids constructions like up-up or down-down as both involved Quarks cannot be differed in this. So, can anyone please help my fault in thinking and grant me a hint, on why two Quarks cannot form a Meson WITHOUT an Anti-Quark / third Quark? Add-on question: if such ud-Quark is not possible, would such construction MAYBE possible in a process when glasma becomes Quark-Gluon-Plasma? This is not a question for a scientific work, neither homework etc. this is just a question to ease my always chatting mind at night as I am very sich, struck with central apnea sleeping disorder and hence my mind ventures into all sorts of science to keep my spirit going. I apologise for any error I made in constructing my question. Thank you.