PHYS08200604017 Manimala Mitra - Homi Bhabha National Institute

5.3. The deviation of the mixing angles from their TBM values can be seen to be
D 12 ≃ 0, D 23 ≃ − ǫ
4d , U e3 ≃ − ǫ
2 √ 2d , (5.15)
where D 12 = sin 2 θ 12 − 1/3 and D 23 = sin 2 θ 23 − 1/2. We show in the left hand panels
of Fig. 5.3 the mixing angles sin 2 θ 12 (upper panel), sin 2 θ 13 (middle panel) and sin 2 θ 23
(lower panel) as a function of ǫ. We vary ǫ from large negative to large positive values
and solve the exact eigenvalue problem numerically allowing the other parameters, m 0 , b
and d, to vary freely. For ǫ = 0 of course we get TBM mixing as expected. For very small
values of ǫ, the deviation of the mixing angles from their TBM values is reproduced well
by the approximate expressions given in Eq. (5.15). For large ǫ of course the approximate
expressions fail and we have significant deviation from TBM. The values of sin 2 θ 12 and
sin 2 θ 13 increase very fast with ǫ, while sin 2 θ 23 decreases with it. We have only showed
the scatter plots up to the 3σ allowed ranges for the mixing angles given in [20]. The
mass dependent observables can be calculated upto first order in ǫ as
∆m 2 21 ≃ m2 0 (b+d+ ǫ 3ǫ
)(3d−b+
2 2 ), ∆m2 31 ≃ (4bd+2bǫ)m2 0 , (5.16)
〈m ee 〉 = m 0
2b
3 , m t = ∑ i
|m i |, m 2 β ≃ m 2 0( 2b2
3 +2d2 − 4bd 2bǫ
+2dǫ−
3 3 ) . (5.17)
Of course, epsilon can be larger and we show numerical results for those cases.
Normal Hierarchy
The right panels of Fig. 5.3 show ∆m 2 21 (upper panel), ∆m 2 31 (middle panel) and m t
(lower panel) as a function of ǫ assuming m 1 < m 2 ≪ m 3 . We show ∆m 2 21 and ∆m2 31
only within their 3σ [20] allowed range. We notice that while ∆m 2 21 and ∆m 2 31 are hardly
constrained by ǫ, there appears to some mild dependence of m t on it.
Fig. 5.4 gives the scatter plots showing the allowed parameter regions for this case.
The upper, middle and lower panels show the allowed points projected on the b−c, d−c
and b−d plane, respectively.
Inverted Hierarchy
For this case it is possible to obtain even inverted hierarchy. We show in Fig. 5.4 the
scatter plots showing the allowed parameter regions for inverted hierarchy. We have
allowed m 0 to vary freely and show the allowed points projected on the c−b, c−d and
d−b planes. Onecancheck thatonly forthepointsappearing inthisplot, m 3 < m 1 < m 2 .
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