相关论文: TASI Lectures on the Strong CP Problem and Axions

The Strong CP Problem and its resolution through the existence of an axion are briefly reviewed. The combined constraints from accelerator searches, the evolution of red giants and the duration of the SN 1987a neutrino pulse require the…

Conventionally, the strong-$CP$ problem is assumed to be a naturalness puzzle, with the axion solution sometimes viewed as an ad hoc fix. Gravity is either ignored or taken as a threat for the global Peccei-Quinn symmetry. We explain that…

The topological susceptibility of the QCD vacuum provides an understanding of $\theta$-vacua as vacua of a Chern-Simons gauge theory. In this way, it gives an immediate proof of the physicality of the boundary $\theta$-term. This makes the…

This proceedings' contribution explores the rationale behind the axion as a resolution to the strong CP puzzle. It outlines various benchmark axion models and examines their implications, focusing on two key aspects: (i) the axion's…

In the first part of this talk, after a brief presentation of the strong CP puzzle, the construction of axion models and their main phenomenological features are described. In the second part, the possibility to mix the Peccei-Quinn…

Observational evidence and theoretical motivation for dark matter are presented and connections to the CMB and BBN are made. Problems for baryonic and neutrino dark matter are summarized. Emphasis is placed on the prospects for…

Axions are hypothetical pseudoscalar particles introduced initially as a solution to the Strong CP problem in Quantum Chromodynamics (QCD), and they also arise naturally in a broad class of low-energy compactifications of string theory.…

I discuss how anomalies affect classical symmetries and how, in turn, the non-trivial nature of the gauge theory vacuum makes these quantum corrections troublesome. Although no solution seems in sight for the cosmological constant problem,…

We investigate what it takes for the axion to address the strong CP problem in the presence of explicit Peccei-Quinn (PQ) symmetry breaking effects besides the strong interaction. In cases where the PQ-Higgsing scalar field directly couples…

The axion is a hypothetical elementary particle postulated by the Peccei-Quinn theory to resolve the strong CP problem in QCD. If axions exist and have low mass, they are a candidate for dark matter as well. So far our knowledge of the…

We review the motivation for the axion as a solution of the strong CP puzzle and as a candidate for cold dark matter. Then we discuss benchmark axion models and present their predictions concerning axion couplings to the Standard Model and…

We analyze the strong CP problem and the implications for axion physics in the context of $U_1$ vector leptoquark models, recently put forward as an elegant solution to the hints of lepton flavor universality violation in B-meson decays. It…

Selected topics in Astroparticle Physics including the CMB, dark matter, BBN, and the variations of fundamental couplings are discussed.

The current status of axion physics is presented. There still exists the axion window 10^9 GeV < F_a < 10^{12} GeV. The recent CAST solar axion search experiment on the axion-photon-photon coupling strength has to be improved by a factor of…

First I will review the QCD theta problem and the Peccei-Quinn solution, with its new particle, the axion. I will review the possibility of the axion as dark matter. If PQ symmetry was restored at some point in the hot early Universe, it…

1. Introduction 2. Models: the QCD axion; the strong CP problem; PQWW, KSVZ, DFSZ; anomalies, instantons and the potential; couplings; axions in string theory 3. Production and I.C.'s: SSB and non-perturbative physics; the axion field…

We show that a recently proposed solution to the Hierarchy Problem simultaneously solves the Strong CP Problem, without requiring an axion or any further new physics. Consistency of black hole physics implies a non-trivial relation between…

We point out that the long-standing strong CP problem may be resolved by an anthropic argument. The key ideas are: (i) to allow explicit breaking(s) of the Peccei-Quinn symmetry which reduces the strong CP problem to the cosmological…

We present a comprehensive study of axion condensed neutron stars that arise in models of an exceptionally light axion that couples to quantum chromodynamics (QCD). These axions solve the strong-charge-parity (CP) problem, but have a…

These lectures, given at the 2014 Theoretical Advanced Study Institute (TASI), are an introduction to what we know at present about dark matter and the major current experimental and observational efforts to identify what it consists of.…