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Related papers: CP-Conservation in QCD and why only "invisible" Ax…

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We use supersymmetric chiral dynamics perturbed by anomaly-mediated supersymmetry breaking to obtain a high-quality, composite axion that solves the strong CP problem. The strong dynamics arises from a supersymmetric SU(10) chiral gauge…

High Energy Physics - Phenomenology · Physics 2025-09-01 T. Gherghetta , H. Murayama , B. Noether , P. Quílez

Axions provide a solution to the strong CP problem and are excellent dark matter candidates. The presence of additional sources of CP violation, for example to account for the matter/antimatter asymmetry of the universe, can lead to…

High Energy Physics - Phenomenology · Physics 2023-12-19 Vaisakh Plakkot , Wouter Dekens , Jordy de Vries , Sachin Shain

It is suggested that the true ground state of the world has exactly vanishing vacuum energy and that the cosmological constant that seems to have been observed is due to our region of the universe being stuck in a false vacuum, whose energy…

High Energy Physics - Phenomenology · Physics 2011-05-12 S. M. Barr , D. Seckel

We study QCD axion or cosmological axion-like particles (ALPs) in a model inspired by the recent interest in 4-dimensional clockwork models, with the global symmetry being accidentally enforced by a gauge abelian quiver with scalar…

High Energy Physics - Phenomenology · Physics 2019-01-21 Quentin Bonnefoy , Emilian Dudas , Stefan Pokorski

Three symmetry constraints on the CP violations in QCD are discussed in this paper. In order to generate CP violating observables from QCD, these constraints require: (1) spontaneous chiral symmetry breaking, (2) explicit chiral symmetry…

High Energy Physics - Phenomenology · Physics 2007-05-23 Chuan-Tsung Chan

In this work, we critically reanalyze the explicit breaking of the Peccei-Quinn global symmetry -- and the corresponding corrections to the QCD axion potential -- induced by gravity. Specifically, we examine the role of gravitational…

High Energy Physics - Theory · Physics 2025-06-23 Pier Giuseppe Catinari , Alfredo Urbano

We review the physics case for CP-violating axions. In the first part, we focus on the Quantum Chromodynamics (QCD) axion and argue that new sources of CP violation beyond QCD misalign the axion solution to the strong CP problem and can…

High Energy Physics - Phenomenology · Physics 2024-01-01 Luca Di Luzio , Hector Gisbert , Gabriele Levati , Paride Paradisi , Philip Sørensen

Murayama proposed a GeV-scale axion theory where the up-quark mass term is generated dynamically by the QCD chiral condensate, spontaneously breaking a Peccei-Quinn symmetry. It predicts a too large mass splitting between neutral and…

High Energy Physics - Phenomenology · Physics 2026-02-25 Luca Di Luzio , Michele Redi , Alessandro Strumia , Andrea Tesi , Arsenii V. Titov

We use a non-invertible symmetry to construct a three-zero texture for the down-type quark mass matrix, which can resolve the strong CP problem without invoking the axion, in four-dimensional spacetime with three quark families in QCD. We…

High Energy Physics - Phenomenology · Physics 2025-05-13 Qiuyue Liang , Tsutomu T. Yanagida

We explore a concrete realization of a Nelson-Barr model addressing the strong CP problem with suppressed unfavorable corrections. This model has a scalar field that spontaneously breaks discrete symmetry, and its phase component can…

High Energy Physics - Phenomenology · Physics 2024-12-30 Kai Murai , Kazunori Nakayama

The QCD axion was originally predicted as a dynamical solution to the strong CP problem. Axion like particles (ALPs) are also a generic prediction of many high energy physics models including string theory. Theoretical models for axions are…

High Energy Physics - Phenomenology · Physics 2017-12-11 David J. E. Marsh

Axions are introduced to explain the observed smallness of the $\bar \theta $ term of QCD. Standard Model extensions typically contain new sources of CP violation, for instance to account for the baryon asymmetry of the universe. In the…

High Energy Physics - Phenomenology · Physics 2022-07-13 W. Dekens , J. de Vries , S. Shain

We explore a dynamical mechanism to realize the emergence of a global $U(1)_{\rm PQ}$ symmetry and its spontaneous breaking at an intermediate scale for an axion solution to the strong CP problem. Such a dynamics is provided by a new…

High Energy Physics - Phenomenology · Physics 2024-01-31 Shota Nakagawa , Yuichiro Nakai , Masaki Yamada , Yufei Zhang

A brief overview is given on the status and prospects of searches for CP nonconservation effects in weak decays of strange, charmed, and beauty hadrons, on the search for permanent electric dipole moments of particles, and on present and…

High Energy Physics - Phenomenology · Physics 2007-05-23 Werner Bernreuther

If the geometry of space-time is $\nc$, i.e. $[x_{\mu},x_{\nu}]=i \theta_{\mu \nu}$, then $\nc$ $\cpviolng$ effects may be manifest at low energies. For a $\nc$ scale $\Lambda \equiv \theta^{-1/2} \leq 2 TeV$, $\cpviol$ from $\ncg$ is…

High Energy Physics - Phenomenology · Physics 2014-11-17 I. Hinchliffe , N. Kersting

The minimal $SO(5)/SO(4)$ linear $\sigma$ model is extended including an additional complex scalar field, singlet under the global $SO(5)$ and the Standard Model gauge symmetries. The presence of this scalar field creates the conditions to…

High Energy Physics - Phenomenology · Physics 2019-11-11 L. Merlo , F. Pobbe , S. Rigolin

We propose a unified model that simultaneously addresses the hierarchy problem and the strong CP problem by considering the most simple fundamental composite Higgs setup and showing that it can feature a viable emergent axion that could be…

High Energy Physics - Phenomenology · Physics 2026-03-05 Florian Goertz , Andrea Incrocci

We discuss matters related to the point that topological quantization in the strong interaction is a consequence of an infinite spacetime volume. Because of the ensuing order of limits, i.e. infinite volume prior to summing over topological…

High Energy Physics - Phenomenology · Physics 2026-05-25 Wen-Yuan Ai , Bjorn Garbrecht , Carlos Tamarit

A spontaneously-broken CP provides an alternative to the KM mechanism for CP violation with the advantage that the strong CP problem is solved. We consider, for such a model with a new gauged U(1), the incorporation of low-energy…

High Energy Physics - Phenomenology · Physics 2009-10-30 Paul H. Frampton , Otto C. W. Kong

The axion mass receives a large correction from small instantons if the QCD gets strongly coupled at high energies. We discuss the size of the new CP violating phases caused by the fact that the small instantons are sensitive to the UV…

High Energy Physics - Phenomenology · Physics 2021-07-28 Ryuichiro Kitano , Wen Yin