Related papers: Calculation of axion-photon-photon coupling in str…
We revisit the question of gauge coupling unification at the string scale in orbifold compactifications of the heterotic string for the supersymmetric Standard Model. In the presence of discrete Wilson lines threshold corrections with…
Understanding axion cosmology has important experimental consequences since it constrains the range of allowed values for the axion mass. In the standard thermal scenario, which assumes Peccei-Quinn symmetry restoration after inflation, an…
We present a brief overview of the ongoing searches for the axion particle via its coupling to photons. Both the classical QCD axions and more recently proposed Axion-Like-Particles are considered. Astrophysical bounds on the axion-photon…
String theory axions appear to be promising candidates for explaining cosmological constant via quintessence. In this paper, we study conditions on the string compactifications under which axion quintessence can happen. For sufficiently…
We demonstrate that the Peccei-Quinn-electromagnetic anomaly coefficient $\mathcal A$ can be directly measured from axion string-induced cosmic birefringence by applying scattering transform to the anisotropic polarization rotation of the…
We derive a strong bound on the axion-photon coupling $g_{a\gamma}$ from the analysis of a sample of 39 Galactic Globular Clusters. As recognized long ago, the R parameter, i.e. the number ratio of stars in horizontal over red giant branch…
Axion is one of the most popular candidates of the cosmological dark matter. Recent studies considering the misalignment production of axions suggest some benchmark axion mass ranges near $m_a \sim 20$ $\mu$eV. For such axion mass, the…
The string one loop renormalization of the gauge coupling constants is examined in abelian orbifold models. The contributions to string threshold corrections independent of the compactification moduli fields are evaluated numerically for…
In certain laboratory experiments the production and/or detection of axions is due to the photon-axion transformations in a strong magnetic field. This process is coherent, and the rate of the transformation is proportional to the length…
We investigate the prospect of an alternative laboratory-based search for the coupling of axions and axion-like particles to photons. Here, the collision of two laser beams resonantly produces axions, and a signal photon is detected after…
We study the cosmological evolution of the QCD axion coupled to hidden photons. For a moderately strong coupling, the motion of the axion field leads to an explosive production of hidden photons by tachyonic instability. We use lattice…
We show that the couplings of axions to gauge bosons are highly restricted in Grand Unified Theories where the standard model is embedded in a simple 4D gauge group. The topological nature of these couplings allows them to be matched from…
In this work we revisit five different point sources within or behind galaxy clusters in order to constrain the coupling constant between axion-like particles (ALPs) and photons. We use three distinct machine learning (ML) techniques and…
We consider the coupling of axions to gauge bosons in higher-dimensional Grand Unified Theories (GUT) inspired by string theory constructions with D-branes on orbifold singularities, the so-called orbifold GUTs. Due to their topological…
We evaluate the pi-N-N, pi-Sigma-Sigma and pi-Sigma-Lambda coupling constants using QCD sum rules based on pion-to-vacuum matrix elements of correlators of two interpolating baryon fields. The parts of the correlators with Dirac structure…
We search for the di-photon decay of a light pseudoscalar axion-like particle, $a$, in radiative $J/\psi$ decays, using 10 billion $J/\psi$ events collected with the BESIII detector. We find no evidence of a signal and set upper limits at…
Axions were originally proposed to explain the strong-CP problem in QCD. Through the axion-photon coupling, the Sun could be a major source of axions, which could be measured in solid state detection experiments with enhancements due to…
Axion couplings to photons could induce photon-axion conversion in the presence of magnetic fields in the Universe. This conversion could impact various cosmic distance measurements, such as luminosity distances to type Ia supernovae and…
We study the renormalization group running of axion couplings while taking into account that the Standard Model can be extended to its supersymmetric extension at a certain energy scale below the axion decay constant. We then apply our…
We employ QCD sum rules to calculate the coupling constant g$_{\rho\sigma\gamma}$ by studying the three point ${\rho\sigma\gamma}$-correlation function. Our results is consistent with the value of this coupling constant obtained using…