Related papers: New confining force solution of QCD axion domain w…
It is known that Yang-Mills theories, especially in the large-$N$ limit, exhibit a $\theta$-vacuum structure with a multi-branched vacuum energy. In this work, we demonstrate that this multi-branch structure can play a crucial role in axion…
We consider the cosmological consequences of a network of superconducting cosmic strings. For strong enough current the period of friction domination never ends. Instead a plasma scaling solution is reached. We demonstrate that this gives…
We discuss a novel mechanism for generating dark matter from a fast-rolling scalar field, relevant for both inflation and rotating axion models, and apply it specifically to the (QCD) axion. Dark matter comes from scalar field fluctuations…
The properties of axion miniclusters and of the voids between them can have very strong implications for the discovery of axions and the dark matter of the Universe. These properties can be strongly affected by axion dynamics in the early…
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…
Axion fields provide the most elegant solution to the strong CP problem. In string compactifications it is difficult to obtain an axion whose decay constant is consistent with current cosmological bounds. We examine this question in…
The axion has emerged in recent years as a leading particle candidate to provide the mysterious dark matter in the cosmos, as we review here for a general scientific audience. We describe first the historical roots of the axion in the…
This paper studies the decay of a large, closed domain wall in a closed universe. Such walls can form in the presence of a broken, discrete symmetry. We introduce a novel process of quantum decay for such a wall, in which the vacuum…
We construct a theory in which the solution to the strong CP problem is an emergent property of the background of the dark matter in the Universe. The role of the axion degree of freedom is played by multi-body collective excitations…
We present a model that solves the strong CP problem via an axion parametrically heavier than the standard one. Within this picture the Standard Model quarks are embedded into a larger non-abelian Grand Color group that at high scales…
Proposed half a century ago, the quantum chromodynamics (QCD) axion explains the lack of charge and parity violation in the strong interactions and is a compelling candidate for cold dark matter. The last decade has seen the rapid…
We calculate a new contribution to the axion mass that arises from gluons propagating in a 5th dimension at high energies. By uplifting the 4D instanton solution to five dimensions, the positive frequency modes of the Kaluza-Klein states…
The main leitmotiv of the present talk is analysis of different topological objects such as strings and domain walls in QCD. As it is well known, the standard model in general (and QCD in particular) does not support any kind of such…
Cosmological evolution of axion field in the early universe might be significantly affected by a thermal friction induced by the axion coupling to thermalized hidden sector. We examine the effects of such a thermal friction on axion dark…
A deeper understanding of the vacuum structure in QCD invites one to rethink certain aspects of the axion physics. The recent advances are mostly due to developments in supersymmetric gauge theories and the brane theory, in which QCD can be…
We point out that a QCD axion solving the strong CP problem can arise naturally from parity-odd gauge field C_M in 5-dimensional (5D) orbifold field theory. The required axion coupling to the QCD anomaly comes from the 5D Chern-Simons…
We propose a new mechanism for explaining the observed asymmetry between matter and antimatter, based on nonperturbative physics at the QCD scale. Our mechanism is a charge separation scenario, making use of domain walls separating the…
Despite growing interest and extensive effort to search for ultralight dark matter in the form of a hypothetical dark photon, how it fits into a consistent cosmology is unclear. Several dark photon dark matter production mechanisms proposed…
I propose a new axionic solution to the strong CP problem which involves a hypothetical vector-like quark(s) in a high-colour representation of the conventional QCD. There are two distinct scenarios. If the current mass of the exotic quark…
If there are a plethora of axions in nature, they may have a complicated potential and create an axion landscape. We study a possibility that one of the axions is so light that it is cosmologically stable, explaining the observed dark…