Abstract
The vanishing of the Higgs quartic coupling of the Standard Model at high energies may be explained by spontaneous breaking of Higgs Parity. Taking Higgs Parity to originate from the Left-Right symmetry of the SO(10) gauge group, leads to a new scheme for precision gauge coupling unification that is consistent with proton decay. We compute the relevant running of couplings and threshold corrections to allow a precise correlation among Standard Model parameters. The scheme has a built-in solution for obtaining a realistic value for mb/mτ , which further improves the precision from gauge coupling unification, allowing the QCD coupling constant to be predicted to the level of 1% or, alternatively, the top quark mass to 0.2%. Future measurements of these parameters may significantly constrain the detailed structure of the theory. We also study an SO(10) embedding of quark and lepton masses, showing how large neutrino mixing is compatible with small quark mixing, and predict a normal neutrino mass hierarchy. The strong CP problem may be explained by combining Higgs Parity with space-time parity.
Highlights
The discoveries of a perturbative Higgs boson at the Large Hadron Collider [1, 2] and no new states beyond the Standard Model (SM) [3, 4] suggest that the SM may be the correct effective theory of particle physics up to a scale orders of magnitude larger than the weak scale, a possibility largely ignored before the Large Hadron Collider
Taking Higgs Parity to originate from the Left-Right symmetry of the SO(10) gauge group, leads to a new scheme for precision gauge coupling unification that is consistent with proton decay
Higgs Parity accounts for a remarkable coincidence: the scale at which the SM quartic coupling vanishes is close to the scale of Left-Right symmetry breaking required for gauge coupling unification in SO(10), as illustrated in figure 1
Summary
The discoveries of a perturbative Higgs boson at the Large Hadron Collider [1, 2] and no new states beyond the Standard Model (SM) [3, 4] suggest that the SM may be the correct effective theory of particle physics up to a scale orders of magnitude larger than the weak scale, a possibility largely ignored before the Large Hadron Collider. This correlation is at best a first order approximation, requiring very large threshold corrections from the unified scale to force the low energy gauge couplings to meet and to make Mu sufficiently large to be consistent with the experimental limit on the proton lifetime.
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