Higgs Boson and Top-Quark Masses and Parity-Symmetry Restoration

Abstract

The recent ATLAS and CMS experiments show the first observations of a new particle in the search for the Standard Model Higgs boson at the LHC. We revisit the scenario that high-dimensional operators of fermions must be present due to the theoretical inconsistency of the fundamental cutoff (quantum gravity) with the parity-violating gauge symmetry of the Standard Model. Studying the four-fermion interaction of the third quark family, we show that at an intermediate energy threshold E\approx 4.27 TeV for the four-fermion coupling being larger than a critical value, the spontaneous symmetry-breaking phase transits to the strong-coupling symmetric phase where composite Dirac fermions form fully preserving the chiral gauge symmetry of the Standard Model and the parity-symmetry is restored. Under this circumstance, we perform the standard analysis of renormalization-group equations of the Standard Model in the spontaneous symmetry-breaking phase. As a result, the Higgs boson mass m_H\approx 126.7 GeV and top-quark mass m_t\approx 172.7 GeV are obtained without drastically fine-tuning the four-fermion coupling.

Comments: 11 pages, 2 figures. the final version to appear in Phys. Lett. B. arXiv admin note: substantial text overlap with arXiv:1301.4254