Interference Phase of Neutrino Oscillation in Schwarzschild-de Sitter Space-Time

We study the mass neutrino interference phase in Schwarzschild-de Sitter space time along the null trajectoryand the geodesic line and obtain the effects of cosmological constant A on the neutrino oscillation. Firstly, in the highenergy limit, we find that the phase along the geodesic keeps the double of that along the null. Secondly, we calculatethe phase on the condition that the cosmological constant, A, is a small quantity. The correction of the phase due to λ isgiven. Finally, we calculate the proper oscillation length in Sehwarzschild-de Sitter space-time, which increases becauseof the existence of λ, compared with the result in Schwarzsehild space-time. All of our results can be reduced to thosein Schwarzschild space-time as λ approaches to zero.