Particle Physics, Interaction Lagrangian Su(2) X U(1), Electroweak theory.

Deadline 23rd April 2013


This is the baisic outline of the problem, but I will upload the actual question sheet.


1) Solve the interaction Lagrangian to show the interactions between the Z boson with quarks.
2) Derive expressions (in terms of the Weinberg angle) for the decay rate of Z to each type of quark and lepton.
Evaluate these decay rates (in units of GeV; remember these formulae are quoted in
h = c = 1 units). Add them up to show that the total decay rate of the Z (i.e. the width
of the Z resonance) is 2.5 GeV.


Specific requirements:
Must have step by step workings and adhere to the form of the Lagrangian in the question. No index notation to be used.

Second question requires that:
CL for neutrinos = 1/2
CL for electrons = -1/2 + Sin^2(Theta_w)
CR for electrons = Sin^2(Theta_w)