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Enhancement of CP Violating terms for Neutrino Oscillation in Earth Matter

Keiichi Kimura·Akira Takamura·Hidekazu Yokomakura
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Abstract

We investigate the $ν_e \to ν_μ$ oscillation in the framework of three generations when neutrinos pass through the earth. The oscillation probability is represented by the form, $P(ν_e \to ν_μ)=A\cos δ+B\sin δ+C$ in arbitrary matter profile by using the leptonic CP phase $δ$. We compare our approximate formula in the previous paper with the formula which includes second order terms of $α=Δm_{21}^2/Δm_{31}^2$ and $s_{13}=\sin θ_{13}$. Non-perturbative effects of $α$ and $s_{13}$ can be taken into account in our formula and the precision of the formula is rather improved around the MSW resonance region. Furthermore, we compare the earth matter effect of $A$ and $B$ with that of $C$ studied by other authors. We show that the magnitude of $A$ and $B$ can reach a few ten % of $C$ around the main three peaks of $C$ in the region $E>1$ GeV by numerical calculation. We give the qualitative understanding of this result by using our approximate formula. The mantle-core effect, which is different from the usual MSW effect, appears not only in $C$ but also in $A$ and $B$, although the effect is weakened.

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Keiichi Kimura, Akira Takamura, Hidekazu Yokomakura. 2005-07-10. Enhancement of CP Violating terms for Neutrino Oscillation in Earth Matter. https://doi.org/10.1016/j.physletb.2004.08.049

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