Related papers: Resurrecting Low-Mass Axion Dark Matter Via a Dyna…
Cold dark matter axions produced in the post-inflationary Peccei-Quinn symmetry breaking scenario serve as clear targets for their experimental detection, since it is in principle possible to give a sharp prediction for their mass once we…
We derive the necessary conditions to build a class of invisible axion models with Flavor Changing Neutral Currents at tree-level controlled by the fermion mixing matrices and present an explicit model implementation. A horizontal…
We present a scale invariant extension of the Standard model allowing for the Kim-Shifman-Vainstein-Zakharov (KSVZ) axion solution of the strong CP problem in QCD. We add the minimal number of new particles and show that the Peccei-Quinn…
We discuss current cosmological constraints on axions, as well as future sensitivities. Bounds on axion hot dark matter are discussed first, and subsequently we discuss both current and future sensitivity to models in which axions play the…
We explore a KSVZ-like extension of the Standard Model with a Dirac fermion and three right-handed neutrinos. PQ symmetry allows the Dirac mass for neutrinos and prevents the Majorana mass. A $\mathcal{Z}_2$ symmetry guarantees the…
We show that, for values of the axion decay constant parametrically close to the GUT scale, the Peccei-Quinn phase transition may naturally occur during warm inflation. This results from interactions between the Peccei-Quinn scalar field…
We discuss the phenomenology of a dark matter scenario in which we extend the Standard Model by a real scalar particle and a vector-like heavy quark. Such a model can be seen as a simplified version of a composite setup in which the scalar…
We show that a supersymmetric axion model naturally induces a hybrid inflation with the waterfall field identified as a Peccei-Quinn scalar. The Peccei-Quinn scale is predicted to be around 10^{15}GeV for reproducing the large-scale density…
A new mechanism for producing axion dark matter is proposed. By invoking low-scale inflation and a kinetic mixing between the axion and the inflaton, it is shown that the axion is driven to a field point slightly displaced from the…
We present a composite QCD axion model where the Peccei--Quinn (PQ) symmetry emerges as a high-quality, accidental symmetry. The axion potential is only modified by eight-fermion, dimension 12 operators, which if present at the Planck…
The axion arises in well-motivated extensions of the Standard Model of particle physics and is regarded as an alternative to the weakly interacting massive particle paradigm to explain the nature of dark matter. In this contribution, we…
The QCD axion and axion-like particles, as leading dark matter candidates, can also have interesting implications for dark matter substructures if the Peccei-Quinn symmetry is broken after inflation. In such a scenario, axion perturbations…
We propose two novel solutions to the domain wall problem of the QCD axion by introducing a massless or light axion that also couples to gluons. The first solution applies when the new axion forms strings after inflation. Due to its mixing…
We discuss the possible sources of dark matter axions in the early universe. In the standard thermal scenario, an axion string network forms at the Peccei-Quinn phase transition $T\sim \fa$ and then radiatively decays into a cosmological…
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…
We highlight a new connection between the Standard Model hierarchy problem and the dark matter sector. The key piece is the relaxion field, which besides scanning the Higgs mass and setting the electroweak scale, also constitutes the…
Recent studies of the cosmic microwave background, large scale structure, and big bang nucleosynthesis (BBN) show trends towards extra radiation. Within the framework of supersymmetric hadronic axion models, we explore two…
Dark matter (DM) can be composed of a collection of axions, or axion-like particles (ALPs), whose existence is due to the spontaneous breaking of the Peccei-Quinn $U(1)$ symmetry which is the most compelling solution of the strong…
Minimal atomic dark matter with its distinctive cooling mechanisms offers an instructive framework for understanding the potential impact of dark matter on small-scale structure formation and early cosmology. The model consists of two…
The secluded dark matter resides within a hidden sector and self-annihilates into lighter mediators which subsequently decay to the Standard Model (SM) particles. Depending on the coupling strength of the mediator to the SM, the hidden…