LANCASTER1	Measuring the muon’s magnetic moment
Type	Experiment and simulation
#students	1
Orientation	Why is the scientific problem of interest at all? All the antimatter in the universe essentially disappeared in the first three minutes after the Big Bang. At present with the known interactions and particles of the Standard Model of Particle Physics there is no way to explain this. An explanation requires there to be new particles or interactions that will likely also manifest themselves in small deviations from the Standard Model predictions of the dipole moments of electrons, muons, protons and neutrons. One of the most sensitive probes is a measurement of the muon’s magnetic dipole moment. This has already been measured to a precision of 0.6 parts per million and presently disagrees with the Standard Model value by 3.5 standard deviations. It is the most precisely measured quantity from an accelerator-based experiment. If this deviation persists with a more accurate measurement then it will be evidence of new physics beyond the Standard Model.
How	How is the research going to shed light on the given problem?. A new experiment at Fermilab, USA is seeking to improve the measurement of the muon’s magnetic moment by reducing the experimental uncertainty by a factor of 4. This will provide a very stringent test of the Standard Model and is sensitive to new types of physics that could also be seen at the LHC but also to new types of interactions e.g. those of dark-photons that the LHC is not sensitive to.
What	What is the specific thing that the student will do, and how does it fit inside the overall project? Crucial to achieving this increase in precision is an improved mapping of the muon's trajectory and the identification of events where two muon decays occur within a few ns of each other. This will be provided by a straw-tracking detector that is being built in the UK. The student will be optimising the design of this straw-tracker using GEANT4/C++ simulation codes and by analysing recent testbeam data of a prototype detector.
Special Knowledge	This project will require strong programming skills
Supervisor	Prof. Mark Lancaster m.lancaster@ucl.ac.uk
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