So below are three more questions on experimental high-energy physics, a bit more accessible than the previous ones. Please try them and report your answers below. The time you spend on the test will not be wasted!
1) The LHC experiments will search for Z bosons in their early 2010 data. The Z decay to muon pairs, in particular, provides a means to verify the correct alignment of tracking detectors and the precise modeling of the magnetic field inside the solenoid, which bends charged tracks traversing its volume.
If the signal cross section equals 50 nanobarns, and only three decays in a hundred produce muon pairs, calculate the integrated luminosity required to identify 100 candidates, assuming that the efficiency with which a muon is detected is 70%.
Hint: you will need to use the formula , and all the information provided above.
2) In the decay of stopped muons, , the produced electron is observed to have an energy spectrum peaking close to the maximum allowed value. What is this maximum value, and what causes the preferential decay to energetic electrons ?
Hint: you might find inspiration in the answer to the first question I posted on Dec. 26th.
3) The decay to an electron-neutrino pair of the W boson occurs one-ninth of the time, because the W may also decay to the other lepton pairs and to light quarks, and the universality of charged weak currents guarantees an equal treatment of all fermion pairs. The question is: if the W boson had a mass of 300 GeV, what would the rate of electron-neutrino decays ?
Hint: the top quark would play a role...
Bonus question: What do you get if you put together three sexy red quarks ?
Answers in a couple of days... Take your thinking hat and start working now!