Phenomenology of long baseline neutrino oscillation Beta Beam experiments and their related technologies

ORME, CHRISTOPHER DAVD (2009) Phenomenology of long baseline neutrino oscillation Beta Beam experiments and their related technologies. Doctoral thesis, Durham University.

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The primary goal of the future experimental program in neutrino oscillation physics is to determine the size of the unknown mixing angle, $\theta_{13}$ , whether CP-violation is present in the leptonic sector and the sign of the atmospheric mass squared splitting. If $\theta_{13}$ is not found by upcoming experiments, then we must turn to intense sources of neutrinos: the Superbeam, Neutrino Factory or Beta Beams. The phenomenon and present status of neutrino oscillations is introduced and future experimental options and some of the strategies summarised. A measurement of $\theta_{13}$ and the CP-phase $\delta$ requires a search of sub-dominant appearance events, such as $\nu_{e}\rightarrow \nu_{\mu}$ . In general, neutrino appearance data can accommodate up to 8 different solutions. This `problem of degeneracies' is discussed and some of the strategies to resolve them are highlighted. A Beta Beam is an intense, clean and collimated electron neutrino beam sourced from the the acceleration of radioactive ions. In this thesis, the ability of Beta Beams, using a neutrino run only, to resolve these degeneracies is explored. The energy dependence of the neutrino oscillation probability and degeneracies is exploited to achieve a good overall CP-violation reach. This approach is adapted to the variants on the Beta Beam idea; namely the electron capture beams and hybrid beams. It is found for all cases considered that the reach is heavily dependent on the event rate with degeneracies causing major problems for low luminosity machines. The need for high event rates suggests that electron capture and hybrid machines will not be competitive without extensive R $\&$ D. The single ion Beta Beam is a viable alternative to the dual ion Beta Beams considered in the literature. Future studies may indicate that it in fact has a better overall physics reach.