Strong thermal $SO(10)$-inspired leptogenesis in the light of recent results from long-baseline neutrino experiments

Abstract

We confront recent experimental results on neutrino mixing parameters with the requirements from strong thermal $SO(10)$-inspired leptogenesis, where the asymmetry is produced from next-to-lightest right-handed neutrinos $N_2$ independently of the initial conditions. There is a nice agreement with latest global analyses supporting $\sin \delta <0$ and normal ordering at $\sim 95\%$ C.L. On the other hand, the more stringent experimental lower bound on the atmospheric mixing angle starts to corner strong thermal $SO(10)$-inspired leptogenesis. Prompted and encouraged by this rapid experimental advance, we obtain a precise determination of the allowed region in the plane $\delta$ versus ${\theta }_{23}$. We confirm that for the benchmark case ${\alpha }_2\equiv m_{D2}/m_{\mathrm{charm}}=5$, where $m_{D2}$ is the intermediate neutrino Dirac mass setting the $N_2$ mass, and initial pre-existing asymmetry $N_{B-L}^{\mathrm{p},\mathrm{i}}=10^{-3}$, the bulk of solutions lies in the first octant. Though most of the solutions are found outside the $95\%$ C.L. experimental region, there is still a big allowed fraction that does not require a too fine-tuned choice of the Majorana phases so that the neutrinoless double beta decay effective neutrino mass allowed range is still $m_{ee}\simeq [10,30]\mathrm{meV}$. We also show how the constraints depend on $N_{B-L}^{\mathrm{p},\mathrm{i}}$ and ${\alpha }_2$. In particular, we show that the current best fit, (${\theta }_{23},\delta )\simeq (47^{\circ },-130^{\circ })$, can be reproduced for $N_{B-L}^{\mathrm{p},\mathrm{i}}=10^{-3}$ and ${\alpha }_2=6$. Such large values for ${\alpha }_2$ have been recently obtained in a few realistic fits within $SO(10)$-inspired models. Finally, we also obtain that current neutrino data rule out $N_{B-L}^{\mathrm{p},\mathrm{i}}\gtrsim 0.1$ for ${\alpha }_2\lesssim 4.7$.

Comments: 21 pages, 5 figures. v2: matching version to be published in JHEP. arXiv admin note: text overlap with arXiv:1705.01935