PHENOMENOLOGICAL ASPECTS OF NEUTRINO OSCILLATION

Abstract

We develop a general and consistent model of neutrino oscillation based on the quantum field theoretical (QFT) description of the neutrino production and detection process. Emphasis is placed on important issues such as locality, causality and unitarity of the entire process; from neutrino production, propagation, to detection. As the result we derived a neutrino count rate formula, which will be useful for making direct connection to experiments. A neutrino flavor oscillation probability arises naturally from this formula, which when compared to the standard oscillation formula currently in use (in neutrino phenomenology), shows modifications which could be significant for short baseline neutrino oscillation experiments. A good feature of this approach is that the neutrino oscillation formula is automatically normalized if the in-going states of the production and detection processes are normalized, instead of the standard approach of having to integrate over propagation time and normalizing the resulting oscillation formula over the final flavors by hand. This is possible in our model because of the sharp edges of the resulting neutrino wave packet, due to some reasonable approximations we employ, which allow us to relate the propagation time to distance. We also provide a critical analysis of the external wave packet model (which is a popular oscillation model), and demonstrate that it possesses some fundamental flaws, namely, a conflict between unitarity and causality, and due to the ambiguous way the external wave packets is introduced, could suggest superluminal signaling with oscillation pattern (contradiction). This same set of analysis is applied to our model, which is found to be free from such defects. The possibility of applying our formula for neutrino count rate to short baseline experiments, which are relevant to the search for sterile neutrinos, is also considered. We also explore an alternative approach to neutrino flavor 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