Why is it easier to see the properties of the c, b, and t quarks in mesons having composition W − or tt - rather than in baryons having a mixture of quarks, such as udb?

If the mass-density of baryonic matter is rhoM = 10^-28 kg m^-3 and the current temperature of the cosmic microwave background is T = 2.7 K, calculate: (a) The mass-density of radiation (i.e rhoR) (b) The photon-baryon ratio (c) The temperature when rhoR = rhoM

You are working as an assistant for a physics professor. For an upcoming lecture, your professor asks you to prepare a presentation slide with the following two proposed reactions which might proceed via the strong interaction:(i) π- + p → K0 +Λ0(ii) π- + p → K0 + nOn the slide, the professor wishes for you to show the quark analysis of the reactions, and (a) identify which reaction is observed, and (b) explain why the other is not observed.

When a p0 decays to two photons, what happens to the quarks of which it was made?