Date of Award

Spring 2011

Document Type

Restricted Thesis

Terms of Use

© 2011 Jonah Bernhard. All rights reserved. Access to this work is restricted to users within the Swarthmore College network and may only be used for non-commercial, educational, and research purposes. Sharing with users outside of the Swarthmore College network is expressly prohibited. For all other uses, including reproduction and distribution, please contact the copyright holder.

Degree Name

Bachelor of Arts


Physics & Astronomy Department

First Advisor

Matthew Mewes


Neutrino oscillations are conventionally accounted for using a three-flavor massive model. This agrees with most experimental data, but fails to accommodate some notable results. A possible explanation is Lorentz violation, which could affect oscillatory behavior. Previous models have used Lorentz violation to describe oscillations with and without neutrino mass. These models have been developed for oscillations in a vacuum or a uniform medium, such as the Earth. However, variable media, such as the Sun, have not been considered.

Solar-neutrino oscillations are studied using a massive model with perturbative Lorentz violation and an approximate model for the composition of the Sun. The adiabatic approximation is used to eliminate high-frequency oscillations and hence obtain analytic expressions for the average probability of detecting each flavor. Lorentz violation is incorporated into the adiabatic results, and changes in energy and directional dependence are considered. Results are more compact than previous work, and are found to be very accurate when compared to exact numerical calculations. The analysis is first carried out for two neutrino flavors and then generalized to include three.

Fits to time-dependent experimental data from the solar-neutrino experiments Super-Kamiokande and the Sudbury Neutrino Observatory are demonstrated, providing approximate values for several combinations of Lorentz-violating coefficients. Most of these results are consistent with zero, but some are not. There is no obvious explanation for this behavior, but it is likely due to uncorrected effects from the eccentricity of Earth's orbit or some other periodic effect.