Improved measurement of the neutral pion decay into electron, positron and photon, and optimisation of the kaon tagger using hydrogen in NA62.

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My research will be carried out as part of the NA62 experiment at CERN. NA62 is a fixed target experiment and is designed to measure rare decays of kaons and pions. It's main aim is to obtain a 10% measurement of the Vtd CKM parameter. A large number of detectors are required to provide the necessary particle identification, high-resolution timing, kinematic rejection and hermetic vetoing of photons. The NA62 experiment uses a Cherenkov detector (known as KTAG) which identifies kaons and pions by detecting the Cherenkov light emitted. The KTAG uses a CEDAR vessel which is filled with nitrogen gas and contains several optical instruments which are finely tuned so that the Cherenkov light emitted by the particles is focused to sets of photomultiplier tubes upstream of the CEDAR. For the initial stage of my research, I will be investigating whether the current optics can be adapted so that instead of using nitrogen gas, hydrogen could be used. This would have the advantage of reducing the multiple scattering of the kaons travelling through the detector. The main part of my research project will be working on an improvement in the single Dalitz decay branching fraction. The current branching fraction measurement of the single Dalitz decay is (1.174 +/- 0.035)%. The aim of my project will be to improve this from a 3% to a 1% measurement.