Towards a muon collider studies from KURNS and MICE

Abstract

The proposed Muon Collider offers two distinct advantages in comparison to lepton and hadron colliders. The larger mass of the muon in comparison to the electron means synchrotron radiation is less of a concern and higher centre of mass collision energies can be reached. Secondly, the muon collider would collide point-like particles in comparison to hadron colliders, resulting in cleaner collision processes. Challenges faced by the Muon Collider are investigated in this thesis. A charge exchange experiment was performed at the Kyoto University Institute for Integrated Radiation and Nuclear Science to investigate electron detachment cross-sections as a function of projectile energy. Results are presented for 11 MeV hydrogen anions striking a carbon foil. Ionisation cooling, an increase in the position and momentum phase-space density of a beam, was investigated by the Muon Ionisation Cooling Experiment (MICE) for various absorber materials. The systematic uncertainties associated with the liquid hydrogen absorber are presented. The ionisation cooling result can be affected by various biases. The MICE momentum reconstruction was biased by the nonuniformity of the magnetic field in the tracker regions of the MICE experiment. It was also biased by misalignments of the solenoid, tracker and magnetic axes. The ionisation cooling result can also be biased by transmission losses. Normalizing the phase space densities by their sample sizes as MICE had done was found to be incorrect. When transmission losses are missing not at random, the changing covariance matrix of the remaining distribution needs to be accounted for as well. Using a transfer matrix approach, a correction procedure was outlined to impute missing data points for the downstream distribution affected by transmission losses. The correct downstream covariance matrix could then be found, meaning the remaining downstream sample could be compared to the full upstream sample unaffected by any biases due to transmission losses.