Exploring the interference between the atmospheric and solar neutrino oscillation subamplitudes

Journal Article · 29 January 2025 · Physical Review. D.

DOI: https://doi.org/10.1103/PhysRevD.111.013007 · OSTI ID:2507376

Barenboim, Gabriela ; Parke, Stephen J.

The interference between the atmospheric and solar neutrino oscillation subamplitudes is said to be responsible for $CP$ violation () in neutrino appearance channels. More precisely, is generated by the interference between the parts of the neutrino oscillation amplitude that are $CP$ even and $CP$ odd: even or odd when the neutrino mixing matrix is replaced with its complex conjugate. This is the interference term, as it gives a contribution to the oscillation probability, the square of the amplitude, which is opposite in sign for neutrinos and antineutrinos and is unique. For this interference to be nonzero, at least two subamplitudes are required. There are, however, other interference terms, which are even under the above exchange, and these are the $CP$ conserving () interference terms. In this paper, we explore in detail these interference terms and show that they cannot be uniquely defined, as one can move pieces of the amplitude from the atmospheric subamplitude to the solar subamplitude and vice versa. This freedom allows one to move the interference terms around, but does not let you eliminate them completely. We also show that there is a reasonable definition of the atmospheric and solar subamplitudes for the appearance channels such that in neutrino disappearance probability there is no atmospheric-solar interference term. However, with this choice, there is a interference term within the atmospheric sector. Published by the American Physical Society 2025

• Research Organization: Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Valencia U.
• Sponsoring Organization: US Department of Energy; USDOE
• Grant/Contract Number: 89243024CSC000002; AC02-07CH11359
• OSTI ID: 2507376
• Report Number(s): FERMILAB-PUB-24-0762-T; 013007
• Journal Information: Physical Review. D., Journal Name: Physical Review. D. Journal Issue: 1 Vol. 111; ISSN PRVDAQ; ISSN 2470-0010
• Publisher: American Physical SocietyCopyright Statement
• Country of Publication: United States
• Language: English