Abstract
In an economical system with only two heavy right-handed neutrinos, we postulate a new texture for 3×2 Dirac mass matrix mD. This model implies one massless light neutrino and thus displays only two patterns of mass spectrum for light neutrinos, namely hierarchical or inverse-hierarchical. Both the cases can correctly reproduce all the current neutrino oscillation data with a unique prediction mνeνe=Δmsolar23 and Δmatm2 for the hierarchical and the inverse-hierarchical cases, respectively, which can be tested in next generation neutrino-less double beta decay experiments. Introducing a single physical CP phase in mD, we examine baryon asymmetry through leptogenesis. Interestingly, through the CP phase there are correlations between the amount of baryon asymmetry and neutrino oscillation parameters. We find that for a fixed CP phase, the hierarchical case also succeeds in generating the observed baryon asymmetry in our universe, plus a non-vanishing Ue3 which is accessible in future baseline neutrino oscillation experiments.
Highlights
The origin of the observed baryon asymmetry in our universe, ratio of number of baryons to photons[1] ηB = nB − nBnγ6.1 ± 0.2 × 10−10, (1)is one of the major problems in cosmology
We find that for a fixed CP phase, the hierarchical case succeeds in generating the observed baryon asymmetry in our universe, plus a non-vanishing Ue3 which is accessible in future baseline neutrino oscillation experiments
Tiny neutrino masses compared to the ordinary quark masses are naturally explained by the see-saw mechanism with heavy right handed neutrinos
Summary
The origin of the observed baryon asymmetry in our universe, ratio of number of baryons to photons[1]. We study lepton asymmetry generated by the CP violating decays of heavy right handed neutrinos (with Majorana mass) at the early stage of our universe. We examine the system with only two right handed neutrinos As discussed above, this system is the minimum one to bring physical CP phases in the lepton sector. We begin with the CP invariant case and apply a simple ansatz to the light neutrino mass matrix so as to reproduce the current best fit values for the neutrino oscillation parameters. With four input parameters (two light and two heavy neutrino mass eigenvalues), all neutrino oscillation parameters as well as the baryon asymmetry through leptogenesis are shown as a function of only the CP phase.
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