scholarly journals Accidental SO(10) axion from gauged flavour

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Luca Di Luzio
Keyword(s):  
Mass Window ◽  
High Quality ◽  
High Scale ◽  
Quality Problem ◽  
Axion Mass ◽  
Grand Unified Theories ◽  
Unified Theories ◽  
Canonical Dimension ◽  
General Perspective ◽  
Effective Operators

Abstract An accidental U(1) Peccei-Quinn (PQ) symmetry automatically arises in a class of SO(10) unified theories upon gauging the SU(3)f flavour group. The PQ symmetry is protected by the ℤ4 × ℤ3 center of SO(10) × SU(3)f up to effective operators of canonical dimension six. However, high-scale contributions to the axion potential posing a PQ quality problem arise only at d = 9. In the pre-inflationary PQ breaking scenario the axion mass window is predicted to be ma ∈ [7 × 10−8, 10−3] eV, where the lower end is bounded by the seesaw scale and the upper end by iso-curvature fluctuations. A high-quality axion, that is immune to the PQ quality problem, is obtained for ma ≳ 2 0.02 eV. We finally offer a general perspective on the PQ quality problem in grand unified theories.

scholarly journals High scale mixing relations as a natural explanation for large neutrino mixing

2016 ◽  
Vol 31 (17) ◽  
pp. 1650095 ◽  
Author(s):  
Gauhar Abbas ◽  
Mehran Zahiri Abyaneh ◽  
Aritra Biswas ◽  
Saurabh Gupta ◽  
Monalisa Patra ◽  
...  
Keyword(s):  
Particle Physics ◽  
Underlying Mechanism ◽  
Neutrino Mixing ◽  
High Scale ◽  
Mixing Angles ◽  
Neutrino Sector ◽  
Grand Unified Theories ◽  
Unified Theories ◽  
General Relations ◽  
Open Question

The origin of small mixing among the quarks and a large mixing among the neutrinos has been an open question in particle physics. In order to answer this question, we postulate general relations among the quarks and the leptonic mixing angles at a high scale, which could be the scale of Grand Unified Theories. The central idea of these relations is that the quark and the leptonic mixing angles can be unified at some high scale either due to some quark–lepton symmetry or some other underlying mechanism and as a consequence, the mixing angles of the leptonic sector are proportional to that of the quark sector. We investigate the phenomenology of the possible relations where the leptonic mixing angles are proportional to the quark mixing angles at the unification scale by taking into account the latest experimental constraints from the neutrino sector. These relations are able to explain the pattern of leptonic mixing at the low scale and thereby hint that these relations could be possible signatures of a quark–lepton symmetry or some other underlying quark–lepton mixing unification mechanism at some high scale linked to Grand Unified Theories.

Water, Water, Here and There

2018 ◽  
Author(s):  
Steven E. Vigdor
Keyword(s):  
Quark Mass ◽  
Mass Difference ◽  
Baryon Number ◽  
Electroweak Phase Transition ◽  
Hydrogen Burning ◽  
Quark Masses ◽  
Grand Unified Theories ◽  
Down Quark ◽  
Unified Theories ◽  
The Stability

Chapter 4 deals with the stability of the proton, hence of hydrogen, and how to reconcile that stability with the baryon number nonconservation (or baryon conservation) needed to establish a matter–antimatter imbalance in the infant universe. Sakharov’s three conditions for establishing a matter–antimatter imbalance are presented. Grand unified theories and experimental searches for proton decay are described. The concept of spontaneous symmetry breaking is introduced in describing the electroweak phase transition in the infant universe. That transition is treated as the potential site for introducing the imbalance between quarks and antiquarks, via either baryogenesis or leptogenesis models. The up–down quark mass difference is presented as essential for providing the stability of hydrogen and of the deuteron, which serves as a crucial stepping stone in stellar hydrogen-burning reactions that generate the energy and elements needed for life. Constraints on quark masses from lattice QCD calculations and violations of chiral symmetry are discussed.

scholarly journals Grand unified theories in renormalisable, classically scale invariant gravity

2019 ◽  
Vol 2019 (10) ◽  
Author(s):  
Martin B. Einhorn ◽  
D.R. Timothy Jones
Keyword(s):  
Scale Invariant ◽  
Grand Unified Theories ◽  
Unified Theories

scholarly journals A composite Higgs with a heavy composite axion

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Tony Gherghetta ◽  
Minh D. Nguyen
Keyword(s):  
Cp Violation ◽  
Gauge Group ◽  
Scalar Fields ◽  
Higgs Model ◽  
Global Symmetry ◽  
Color Group ◽  
High Scale ◽  
Axion Mass ◽  
Composite Higgs ◽  
The Standard Model

Abstract We consider the strong dynamics associated with a composite Higgs model that simultaneously produces dynamical axions and solves the strong CP problem. The strong dynamics arises from a new Sp or SU(4) hypercolor gauge group containing QCD colored hyperfermions that confines at a high scale. The hypercolor global symmetry is weakly gauged by the Standard Model electroweak gauge group and an enlarged color group, SU(N + 3) × SU(N)′. When hyperfermion condensates form, they not only lead to an SU(5)/SO(5) composite Higgs model but also spontaneously break the enlarged color group to SU(3)c× SU(N)D. At lower energies, the SU(N)D group confines, producing two dynamical axions that eliminates all CP violation. Furthermore, small instantons from the SU(N)′ group can enhance the axion mass, giving rise to TeV scale axion masses that can be detected at collider experiments. Our model provides a way to unify the composite Higgs with dynamical axions, without introducing new elementary scalar fields, while also extending the range of axion masses that addresses the strong CP problem.

Mass scales in grand unified theories

1982 ◽  
Vol 26 (9) ◽  
pp. 2396-2419 ◽  
Author(s):  
R. W. Robinett ◽  
Jonathan L. Rosner
Keyword(s):  
Grand Unified Theories ◽  
Unified Theories

Cosmological consequences of grand unified theories on density fluctuations

Nature ◽  
1981 ◽  
Vol 291 (5811) ◽  
pp. 133-134 ◽  
Author(s):  
David Lindley
Keyword(s):  
Density Fluctuations ◽  
Grand Unified Theories ◽  
Unified Theories

scholarly journals The LHC Higgs boson discovery: Implications for Finite Unified Theories

2014 ◽  
Vol 29 (18) ◽  
pp. 1430032 ◽  
Author(s):  
S. Heinemeyer ◽  
M. Mondragón ◽  
G. Zoupanos
Keyword(s):  
Higgs Boson ◽  
Predictive Power ◽  
Low Energy ◽  
Boson Mass ◽  
Higgs Boson Mass ◽  
Light Higgs Boson ◽  
Quark Masses ◽  
Grand Unified Theories ◽  
Unified Theories ◽  
Discovery Potential

Finite Unified Theories (FUTs) are N = 1 supersymmetric Grand Unified Theories (GUTs) which can be made finite to all-loop orders, based on the principle of reduction of couplings, and therefore are provided with a large predictive power. We confront the predictions of an SU(5) FUT with the top and bottom quark masses and other low-energy experimental constraints, resulting in a relatively heavy SUSY spectrum, naturally consistent with the nonobservation of those particles at the LHC. The light Higgs boson mass is automatically predicted in the range compatible with the Higgs discovery at the LHC. Requiring a light Higgs boson mass in the precise range of Mh= 125.6 ±2.1 GeV favors the lower part of the allowed spectrum, resulting in clear predictions for the discovery potential at current and future pp, as well as future e+e-colliders.

Sign in / Sign up

Export Citation Format

Share Document