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Events on Tuesday, April 30th, 2024

Modeling Solar Neutrino Flavor Evolution with Data Assimilation
Time: 11:00 am - 1:00 pm
Place: 5280 Chamberlin;
Speaker: Caroline Laber-Smith
Abstract: This talk will cover the application of statistical data assimilation (SDA) techniques to solar neutrinos in two cases. Statistical data assimilation is an inference method that incorporates system dynamics from theory to supplement sparse measurements. Solutions are found by minimizing deviation from both measurements and model dynamics and tested based on their predicted results outside of the measured region. We used this technique to model neutrino flavor evolution throughout the sun, starting from pure electron flavor at the center and undergoing Mikheyev-Smirnov-Wolfenstein (MSW) resonance as it travels outwards.

This is the first application of SDA to solar neutrinos using real data - measurements of Boron-8 solar neutrino flavor recorded by the Borexino and Sudbury Neutrino Observation (SNO) experiments were used to constrain neutrino flavor towards the edge of the sun. In the first case, we used this data as a test of the technique. We performed this optimization procedure with multiple energy bins matching the observations from the Borexino and SNO experiments separately. With both sets of measurements, we found that incorporating MSW resonance into the flavor evolution dynamics produces results consistent with the observations.

In the second case, we introduced parameter estimation by allowing the procedure to vary the matter potential inside the sun. As a test of adiabaticity, we used two different monotonically decreasing models of the matter potential as a function of radius. For each model, the potential was held fixed at the edge of our zone of inference to match the standard solar model, while the value at the core of the sun was used as a varying parameter. For both models, we found that a core potential between 0.025 and 0.030 per kilometer produces results most consistent with observed neutrino fluxes.
Host: Baha Balantekin
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