Solar neutrino oscillations in the quasi-vacuum regime

Abstract

Motivated by recent experimental data, we study solar neutrino oscillations in the range 10^-10 < delta m^2/E < 10^-7 eV^2/MeV. In this range vacuum oscillations become increasingly affected by (solar and terrestrial) matter effects for increasing delta m^2, smoothly reaching the MSW regime. A numerical study of matter effects in such "quasi-vacuum" regime is performed. The results are applied to the analysis of the recent solar neutrino phenomenology.

Comments: 4 pages, 2 figures. Talk given at Europhysics Neutrino Oscillation Workshop (NOW 2000), Conca Specchiulla, Otranto, Lecce, Italy, 9-16 Sep 2000. Figure 2 corrected