Introduction to HEP
Thursday, 9 January 1996

Physics is an experimental science, so everything should have a quantitative experimental foundation. This course is mostly about standard topics, but in this problem you have a chance to sharpen your critical abilities on some basic issues ranging from the almost standard to the rarely thought of.

Answer just one of the following (i.e. Choose one part to answer, not all of them!) You will get a mark of at least 90% as long as it is clear that you have tried to find the answer and thought about the question.

What is the best (if any) experimental or observational evidence that indicates:

1. energy is conserved?
2. each individual quark has a fractional electric charge?
3. SU(3)_colour is an exact symmetry?
4. there is no gauge boson coupling to lepton number?
5. there are only 3 spatial dimensions and 1 time dimension?
6. strange quarks are point particles?
7. muons obey Fermi-Dirac statistics?
8. up quarks and charm quarks have the same electric charge?
9. there are not more quarks or leptons to be discovered?
10. the fine structure constant is constant?
11. the Z⁰ boson has a universal coupling to all point fermions?

These questions could each be the subject for a long report (in fact, many of them are research questions I occasionally work on), but your answer must be less than two pages (i.e. one double-sided sheet). Be as quantitative as possible. You should cite original papers (including the full title of the paper) for any experimental data. In some cases the evidence may be indirect and require some theoretical filtering. Come and talk to me if you have trouble getting started, or if you don't understand what I am asking for.