ABSTRACT
The C P violation in the neutrino flavor oscillations relates directly to the C P violating phase cP in the mixing matrix for massive neutrinos. Direct measurements of C P violation originated from the phase cP are differences of transition probabilities between C P-conjugate channels [5, 6J:
D.Pcp = P(fi", -'> fie) - P(Vp -'> Ve ) = P(Vp -'> Vr ) - P(I/p -'> fir) P(I/e -'> fir) - P(Ve -'> Vr ) = 4Jcpicp , (1)
icp == sin D.12 + sin D.23 + sin D.31 , 2 L D.ij = D.mij 2E ' and the rephasing invariant quantity Jop is given as
(2)
(3)
On the other hand, lop depends on mixing angles. The mixings 823, 812 and 813 are constrained by atmospheric neutrinos, solar neutrinos and CHOOZ experiments [10]' respectively. We take 823 = 1/V2, which is the typical mixing angle from the atmospheric neutrino data, and 813 ::; 0.2 from the CHOOZ data. Since larger mixings give larger lop, the large mixing angle solution of the solar neutrino is favored to search for C P
The magnitude of 6P can reach 10-3 ""' 10-2 in the case of 6mb ::::= 1O-4ey2 [3]. The vacuum oscillation solution is un favor for observing CP violation since icp is considerably suppressed due to 6mb c::: 1O-lOey2. Then, 6P is at most 10-8 . If we use the small angle MSW solution, 6P is at most 10-4 due to the small mixing angle 812 ""' 0.04. In conclusion, one can expect to observe the C P violating effect in neutrino oscillations when the large mixing angle MSvV solution is the true solution in the solar neutrino problem. Therefore, we show numerical calculations by taking this solution in this letter.
