Resonances of Supernova Neutrinos in Twisting Magnetic Fields

We investigate the effect of resonant spin conversion of the neutrinos induced by the geometrical phase in a twisting magnetic field. We find that the geometrical phase originating from the rotation of the transverse magnetic field along the neutrino trajectory can trigger a resonant spin conversion of Dirac neutrinos inside the supernova, even if there were no such transitions in the fixed-direction field case. We have shown that, even though resonant spin conversion is too weak to affect solar neutrinos, it could have a remarkable consequence on supernova neutronization bursts where very intense magnetic fields are quite likely. We demonstrate how the flavor composition at Earth can be used as a probe to establish the presence of non-negligible magnetic moments, potentially down to <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:msup><a:mrow><a:mn>10</a:mn></a:mrow><a:mrow><a:mo>−</a:mo><a:mn>15</a:mn></a:mrow></a:msup><a:msub><a:mrow><a:mi>μ</a:mi></a:mrow><a:mrow><a:mi>B</a:mi></a:mrow></a:msub></a:mrow></a:math> in upcoming neutrino experiments like the Deep Underground Neutrino Experiment and the Hyper-Kamiokande. Possible implications are analyzed. Published by the American Physical Society 2024