Related papers: Semiclassical Gravity and Invisible Axions
We show that the required high quality of the Peccei-Quinn symmetry can be naturally explained in the aligned QCD axion models where the QCD axion arises from multiple axions with decay constants much smaller than the axion window, e.g.,…
In this contribution, I'll discuss two classes of effects--additional sources of CP violation and PQ breaking--that offer a slightly different take on axion physics. Both are tied to the idea that the axion solution to the strong CP problem…
We review the status of axino dark matter. Two hierarchy problems, the strong CP problem and the gauge hierarchy problem, have led to introducing into particle physics a spontaneously broken global Peccei-Quinn symmetry and a softly broken…
Although the axion is the most compelling solution to the strong CP problem, the ad hoc introduced global Peccei-Quinn symmetry suffers from a severe fine-tuning problem known as the quality problem. In this Letter, we show that the…
In an attempt to uncover any underlying physics in the standard model (SM), we suggest a $\mu$--$\tau$ power law in the lepton sector, such that relatively large 13 mixing angle with bi-large ones can be derived. On the basis of this, we…
We propose a novel minimal scenario which simultaneously addresses the following theoretical/cosmological/phenomenological puzzles: (i) the origin of scales, (ii) primordial inflation, (iii) matter-antimatter asymmetry, (iv) tiny neutrino…
We present a model based on the $SU(3)_C\otimes SU(3)_L\otimes U(1)_X$ gauge symmetry that relates the mass hierarchy of the fermions with the solution to the strong CP problem through the $U(1)_{PQ}$ Peccei-Quinn symmetry. This last…
A $SU(N)_L\times SU(N)_R$ gauge theory for a scalar multiplet $Y$ transforming in the bi-fundamental representation $(N,\bar N)$ preserves, for $N>4$, an accidental $U(1)$ symmetry firstly broken at operator dimension $N$. Two…
A simple hadronic axion model is proposed in the framework of gauge-mediated supersymmetry breaking. Dynamics of Peccei-Quinn symmetry breaking is governed by supersymmetry breaking effects and the Peccei-Quinn breaking scale $f_{PQ}$ is…
On the basis of the coincidence of the physical dimensions (in natural units $\hbar = c = 1$) of the Newton's gravitational constant $G_{N} $ and the phenomenological Fermi constant $G_{F} $ for weak interaction, it is suggested that there…
We argue that the axion arising in the solution of the strong CP problem can be identified with the Majoron, the (pseudo-)Goldstone boson of spontaneously broken lepton number symmetry. At low energies, the associated $U(1)_L$ becomes, via…
Using the path integral approach, we derive the low energy interactions between axions and electromagnetic field that arise in models with heavy dyons charged under a spontaneously broken global axial $U(1)$ symmetry. Hence, we obtain…
We consider the axion arising from five-dimensional supergravity in the presence of boundaries. We find the approximate bosonic effective action to estimate the lower bound on the "Peccei-Quinn" energy scale with a flat bulk. With a warped…
We discuss some subtleties which arise in the semiclassical approximation to quantum gravity. We show that integrability conditions prevent the existence of Tomonaga-Schwinger time functions on the space of three-metrics but admit them on…
We propose two models where a U(1) Peccei-Quinn global symmetry arises accidentally and is respected up to high-dimensional operators, so that the axion solution to the strong CP problem is successful even in the presence of…
Many models of dark matter QCD axion requires inflation at a scale $H_{\text{inf}} \lesssim 10^{6}$~GeV and hence does not allow for a detectable tensor mode fluctuation. This is because the domain wall problem forces the Peccei--Quinn…
We explore a new class of axion models in which some, but not all, of the left-handed quarks have a Peccei-Quinn symmetry. These models are potentially afflicted by flavour changing neutral currents. We derive the bounds on the Peccei-Quinn…
Pecci-Quinn (PQ) symmetry breaking by perturbative dynamics would suffer from a hierarchy problem, just like the electroweak symmetry breaking in the standard model. The dynamics of the axion, associated with the PQ symmetry breaking, would…
We review a class of models which generalize the traditional Peccei-Quinn (PQ) axion solution by a St\"uckelberg pseudoscalar. Such axion models represent a significant variant with respect to earlier scenarios where axion fields were…
The QCD axion is widely studied as a dark matter (DM) candidate and as a solution to the strong CP problem of the Standard Model. In conventional field-theoretic models, a much larger mass scale than the electroweak (EW) scale is typically…