Rutgers Physics 418 Nuclei & Particles (Somalwar)

Homework 9 - Due December 1, 2017

Das & Ferbel refers to the textbook Introduction to Nuclear and Particle Physics, 2nd Edition, by A. Das and T. Ferbel

Read entire Chapter 11

1) Das & Ferbel, Problem 11.2.

2) Das & Ferbel, Problem 11.3. In each case, comment on the preferred direction of the pions, i.e., along or perpendicular to the Z-axis. By taking into account all the spin projections (0, +1 and -1), show that the distribution is spherically symmetric for unpolarized rho's.

3) Das & Ferbel, Problem 11.4. (A trick question? Note that the decay is weak.)

4) Das & Ferbel, Problem 11.5. For part (d), don't forget that both symmetric and antisymmetric combinations are possible for the final state.

5) The running QCD coupling constant αs can written as αs = 12π/(33-2f)ln(Q22) , where Λ is a parameter which is chosen to fit experiments and takes a value of about 500 MeV. In this formula f is the available number of quark flavors which increases from 3 (u,d,s) at Q2 = (1GeV)2 to 5 at Q2 = (10GeV)2 (all but the top quark). Use this formula to calculate αs at these two values of Q2.