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High Energy Physics - Phenomenology, hep-ph
Abstract:
We perform numerical fits of Grand Unified Models based on SO(10), using
various combinations of 10-, 120- and 126-dimensional Higgs representations.
Both the supersymmetric and non-supersymmetric versions are fitted, as well as
both possible neutrino mass orderings. In contrast to most previous works, we
perform the fits at the weak scale, i.e. we use RG evolution from the GUT
scale, at which the GUT-relations between the various Yukawa coupling matrices
hold, down to the weak scale. In addition, the right-handed neutrinos of the
seesaw mechanism are integrated out one by one in the RG running. Other new
features are the inclusion of recent results on the reactor neutrino mixing
angle and the Higgs mass (in the non-SUSY case). As expected from vacuum
stability considerations, the low Higgs mass and the large top-quark Yukawa
coupling cause some pressure on the fits. A lower top-quark mass, as sometimes
argued to be the result of a more consistent extraction from experimental
results, can relieve this pressure and improve the fits. We give predictions
for neutrino masses, including the effective one for neutrinoless double beta
decay, as well as the atmospheric neutrino mixing angle and the leptonic CP
phase for neutrino oscillations.
