https://doi.org/10.1140/epjp/s13360-024-05296-8
Regular Article
Effect of spacetime geometry on neutrino oscillations
S. N. Bose National Centre for Basic Sciences, Block JD, Sector 3, 700106, Salt Lake, WB, India
Received:
8
February
2024
Accepted:
18
May
2024
Published online:
1
June
2024
Propagation of fermions in spacetime requires a spin connection, which can be split into a universal gravitational part and a non-universal “contorsion” part. The latter is non-dynamical and can be eliminated from the theory, leaving an effective four-fermion interaction with unknown coupling constants. The generic form of the contorsion-fermion coupling, and thus the four-fermion interaction, breaks chiral symmetry. This interaction affects all fermions—in particular neutrinos passing through matter will notice a contribution to their effective Hamiltonian, just like the MSW effect coming from weak interactions, but diagonal in the mass basis rather than the flavor basis. Then there is a possibility that this geometrical contribution is not negligible for neutrinos passing through normal matter, provided the coupling constants are not too small. We calculate the matter potential due to this interaction and thus write the conversion and survival probabilities including its effect. We plot conversion probabilities of 
to 
and 
for a baseline of 1300 km, as well as their dependence on the CP phase, with and without the geometrical interaction. We also plot the survival probability of reactor 
for different baselines.
Copyright comment Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2024. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
