Tri-bimaximal Neutrino Mixing and Flavor-dependent Resonant Leptogenesis · arXivDesk
hep-ph/0607302Jul 27, 2006REVTeX4 18 pages (including 1 PS figure). Title and Abstract changed; flavor effects in leptogenesis recalculated, new results obtained and discussions extended; A comparison between different formulas of CP asymmetries in resonant leptogenesis performed; references updated. Accepted for publication in PLB
Tri-bimaximal Neutrino Mixing and Flavor-dependent Resonant Leptogenesis
We propose a particularly economical neutrino mass model, in which there are only two right-handed Majorana neutrinos of O(1) TeV and their masses are highly degenerate. Its novel Yukawa-coupling texture together with the seesaw mechanism allows us to achieve the normal neutrino mass hierarchy with m1=0 and a nearly tri-bimaximal neutrino mixing pattern with the maximal CP-violating phase: θ23=π/4
Nearby in the stack
,
∣δ∣=π/2
and
sin2θ12=(1−2tan2θ13)/3
. One may also obtain the inverted neutrino mass hierarchy with
m3=0
and the corresponding neutrino mixing pattern with
θ23=π/4
and
θ13=δ=0
. In both cases, it is possible to interpret the cosmological baryon number asymmetry
ηB≈6.1×10−10
through the resonant leptogenesis mechanism. We demonstrate the significance of flavor-dependent effects in this leptogenesis scenario: they can either flip the sign of the flavor-independent prediction for
ηB
in the
m1=0
case or magnify the magnitude of the flavor-independent prediction for