Homework Problem due on February 20
[20 points]
The lifetime of the muon is about 2.2 x 10^{-6} seconds and the
lifetime of the neutron is about 930 seconds.
Both are said to be weak nuclear decays.
In class we found that the matrix element for muon decay is proportional
to the fifth power of the muon mass.
The neutron is more massive than is the muon.
Consider the phase space available for neutron decay and for muon decay
and compare the magnitudes of the matrix elements of these two decays.
Recall that these are both three-body decays.
The arguments you present should be qualitatively compelling, but only
semi-quantitative.
Do not reproduce the calculation of section 10.3 of Griffiths.
Rather, present a back-of-the-envelope calculation that an undergraduate
taking a first course in quantum mechanics could understand.
last modified February 11, 2002