Master & PhD defense exam at UZH CMS

Some typical questions during exams at UZH:

• Questions about your analysis or thesis (obviously).
  • What is the theoretical or experimental motivation of your model? What motivates your particular chosen set or range of parameter values?
  • What are motivated variations of your signal model? E.g. different mass or coupling parameters.
  • What is the broader context of your model in other experiments? This can be past, current or future experiments like LEP, Tevatron, or LH-LHC. How would your signal show up there? What would the backgrounds be? What exclusions do they give?
  • How would your signal and analysis change with more luminosity (e.g. Run3, LH-LHC data) or higher center of mass energy? (Future colliders.)
  • Questions on the process, like the color flow of Feynman diagram, or parton (like initial b quark) coming from the protons (see PDFs below), …
  • Is the uncertainty in your result statistically or systematically driven? (Yuta's favorite.)
  • Specifics about certain systematics (nuisance parameters): Which (background) systematics are important? How can they be constrained? …
• Detector / accelerations questions:
  • PDFs at LHC (quark, b quark, gluon content of proton and anti-proton), see bottom plots.
  • Difference between LHC, LEP, and Tevatron; advantages/disadvantages, production mechanisms, …
• Higgs physics
  • In particular the different Higgs production mechanism at the LHC or LEP. See e.g. this article on LEP, this CMS article in Nature, this paper on LHC, or the complete set of cross section and branching plots here.
  • If you are very unlucky the Higgs mechanism.
• Especially for PhD exams:
  • About anything you wrote in your thesis.
  • SM Lagrangians (see page 8), or maybe that of your BSM signal model.
  • Hadronization (formation of jet).
  • Neutrinos: oscillations, seesaw mechanism, …
  • Statistics at the LHC: type of test statistics, how to get exclusion limits (upper limits), … See e.g. these lectures, or this talk.
  • Details about your object reconstruction & identification algorithms (taus, jets, b tagging, …)
  • How is luminosity measured? See e.g. this CMS article, this PAS, or this ATLAS talk.
  • For what was the Nobel Prize in Physics awarded this/last year? See this Wikipedia page.
• …

• You will notice that often the questions are asked awkwardly, and they will repeat them, because the examiner is phishing for a very particular word or phrase.
• If you do not know what they are looking for, or you do not understand the question, just ask to clarify, and try to have more of an active discussion than an interrogation.
• As a “cheat” or “hack”, you can prepare a lot of material in the back up of your presentation.