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

The primary goal of the future experimental program in neutrino oscillation physics is to determine the size of the unknown mixing angle, θ₁₃, whether CP-violation is present in the leptonic sector and the sign of the atmospheric mass squared splitting. If θ₁₃ 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 θ₁₃ and the CP-phase δ requires a search of sub-dominant appearance events, such as \nu_e\rightarrow \nu_μ. 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.

Name dc:type.qualificationname

PhD

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

Durham University

Year dc:date.issued

2009

Author dc:creator

• Orme, Christopher Davd