3. (i) Explain the role of the CKM matrix in the Standard Model. [1 mark] (ii) Explain how the presence of non-zero off-diagonal terms allows some neutral matter mesons to turn into their antimatter partners. Several Feynman diagram B meson mixing. Draw the diagram with the largest contribution. Label the CKM matrix elements on vertices. [2 marks] (iii) Discuss whether leptons can turn into their antimatter particles. Draw a representative Feynman diagram responsible for neutrino mixing. [2 marks] (iv) Explain why the rate at which matter turns into anti-matter differs from the rate for the reverse process. How is this accommodated in the Standard Model? [2 marks] (v) The branching fraction for the decay B Dat is equal to 2.7x10-3. Explain why the branching fraction for B D+ is much smaller, and make an estimate of its size. [3 marks) .974 227 .004 Note that the magnitudes of the CKM matrix elements are: .227 973 .042 1.008.042 999 3. (i) Explain the role of the CKM matrix in the Standard Model. [1 mark] (ii) Explain how the presence of non-zero off-diagonal terms allows some neutral matter mesons to turn into their antimatter partners. Several Feynman diagram B meson mixing. Draw the diagram with the largest contribution. Label the CKM matrix elements on vertices. [2 marks] (iii) Discuss whether leptons can turn into their antimatter particles. Draw a representative Feynman diagram responsible for neutrino mixing. [2 marks] (iv) Explain why the rate at which matter turns into anti-matter differs from the rate for the reverse process. How is this accommodated in the Standard Model? [2 marks] (v) The branching fraction for the decay B Dat is equal to 2.7x10-3. Explain why the branching fraction for B D+ is much smaller, and make an estimate of its size. [3 marks) .974 227 .004 Note that the magnitudes of the CKM matrix elements are: .227 973 .042 1.008.042 999