Question

could you please answer all parts of this question. like and comment are rewarded.

Compulsory question: [8] A1. (a) Consider the following processes (i) + +n+p+et te (ii) H+ e + e + D (iii) + +et+ve (iv) K+ + + + V Use conservation laws to determine which of these processes are allowed. For processes that are not allowed, state which conservation laws are violated. For processes that are allowed, specify by which interaction (electromagnetic, weak or strong) they proceed. (b) The Aº baryon has quark composition uds and decays as follows Aº +p+ The Aº baryon has quark composition udd and decays as follows Aº +p+ Draw Feynman diagrams for each decay. Explain why the lifetimes of the Aº and Aº baryons are different. (c) Collisions of high-energy particles in the upper atmosphere, 8 km from the Earth's surface, producent and ut particles. Assuming that the it and ut each have a speed of 0.998c, determine whether the #t and ut can be ob- served at the Earth's surface. You may assume that the masses of the particles are m = 105.7 MeV/c and m. = 139.6 MeV/c?, and that the lifetimes are Tut = 2.2 x 10-6s and T+ = 2.6 x 10-8 s. (d) With the aid of a diagram showing cross section versus energy, explain what the term resonance means. 18 [8] 6

Answer 1

CONCLUSION-

AI. 1 I ) +/ +/ - Cal consider the following processes (i)xt t n Ptett e- to 1+1 - 1 --- conserved B 0 +1 1 +0+o conserved I + 1/2 (not conserved) Iz (conserved) S + o +0+0 As=0 The decay process is allowed by EM interaction (ii) e é + e + Du - 1 toto Lp +1 o tot not conserved B. o toto 0 +0+ 0 tre - - not conserved. o 0 1 The decay process is not allowed here. Ci e forbidden). (iii) at et the +1 ti to - + 1 O to inah Hoor o O 0 - - O - o to --- hot conserved - - - not conserved 0+ 0 0+ Hence the decay process is allowed by weak Interaction. (iv) kt rett Vre +1 +1 to Q B not conserved Iz S 0 ASE-1 (decay process is allowed by weak Interaction)

WO IF AS = 0 the process will be strong, EM or it may a weak in teraction also be Type of Interactions AS ΔΙ AI3 Strong O Electromagnetic Х xo Weak 0 II Х 2