Question

Briefly discuss the essentials of the quark model for strongly interacting particles. In your discussion specify the baryon number, spin and charge of each of the quarks, explain what is meant by flavour, colour(-charge) and quark confinement. State the quark composition of mesons and hadrons, and explain why there are only quark- antiquark combinations, and combinations of three quarks and of three anti-quarks 4. (a) (4 marks) 0, Л0--, and According to the Eightfold Way, the light baryons p, n, arranged in an octet. These baryons all have JP, and are each composed of the lightest 3 quarks. In the baryon octet combinations of three identical quarks are forbidden by the Pauli exclusion principle (b) o can be , Construct this baryon octet, and indicate in your diagram the charge Q, the strangeness S, and the quark content of each of these baryons. (i) (2 marks) (ii) The light baryons can be arranged in multiplets with isospin 1 that the number of particles in each multiplet are distinguished by the possible values of the z-component of the isospin 13 =-1,-1 +1 … +1. Identify all multiplets in the baryon octet (including singlets), and briefly explain the relevance of introducing isospirn 0, %, and 1, such (2 marks) (iii) 0, + each decay via the strong interaction into a proton The sigma baryons and a pion or a neutron and a pion. Given that there are 5 possible decays in total, write down the decay equation for each of these decays , (2 marks)

Answer 1

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