Related papers: Calculation of axion-photon-photon coupling in str…
We argue that the QCD axion can arise from many aligned axions with decay constants much smaller than the conventional axion window. If the typical decay constant is of {\cal O}{(100)} GeV to 1 TeV, one or more of the axions or saxions may…
We study the production of cosmological axions in the standard scenario in which a global string network forms at the Peccei-Quinn phase transition. We make detailed calculations of the axions produced by string loops (a previously…
We present a new statistical analysis that combines helioseismology (sound speed, surface helium and convective radius) and solar neutrino observations (the $^8$B and $^7$Be fluxes) to place upper limits to the properties of non standard…
The post-inflationary Peccei-Quinn (PQ) symmetry breaking scenario provides a unique opportunity to pinpoint the QCD axion dark matter mass, which is a crucial input for laboratory experiments that are designed for probing specific mass…
The coupling constants g$_{\rho\eta\gamma}$ and g$_{\omega\eta\gamma}$ are calculated using QCD sum rules method by studying the three point ${\rho\eta\gamma}$ and ${\omega\eta\gamma}$ correlation functions. A comparison of the results with…
Axion dark matter differentiates the phase velocities of the circular-polarized photons. In Phys.Rev.Lett. 123 (2019) no.11, 111301, we have proposed a scheme to measure the phase difference by using a linear optical cavity. If the scheme…
Markarian 421 is a well-known nearby BL Lac blazar at the redshift $z=0.031$. Many previous works were investigated to constrain the axion-photon coupling from its TeV gamma-ray observations, showing the upper limit on the coupling constant…
We analyze gauge coupling unification in the context of heterotic strings on anisotropic orbifolds. This construction is very much analogous to effective 5 dimensional orbifold GUT field theories. Our analysis assumes three fundamental…
The Peccei-Quinn ($PQ$) mechanism is applied to the $\mathrm{SU(3)_c \otimes SU(3)_L \otimes U(1)_X}$ model with $U(1)_{B-L}$ symmetry. The structures in the $PQ$ charges of all fermions and scalar fields in the model are investigated by…
The QCD axion can successfully solve the strong CP problem under the condition that the Peccei-Quinn symmetry is respected to extremely high standard. We explore a class of gauge theories that accommodate a high-quality axion, known as the…
The external-field QCD Sum Rules method is used to evaluate the coupling constant of the light isoscalar-scalar meson (``$\sigma$'' or \epsilon) to the nucleon. The contributions that come from the excited nucleon states and the response of…
Thermally emitting neutron stars represent a promising environment for probing the properties of axion-like particles. Due to the strong magnetic fields of these sources, surface photons may partially convert into such particles in the…
The status of the solar axion search with the CERN Axion Solar Telescope (CAST) will be presented. Recent results obtained by the use of $^3$He as a buffer gas has allowed us to extend our sensitivity to higher axion masses than our…
It is demonstrated that detection of putative particles such as paraphotons and axions constituting the dark sector of the universe can be reduced to detection of extremely weak links or couplings between cavities and modes. This method…
A sample of 3984 candidates of the $K^+\to\pi^+\gamma\gamma$ decay, with an estimated background of $291\pm14$ events, was collected by the NA62 experiment at CERN during 2017-2018. In order to describe the observed di-photon mass spectrum,…
Polarization measurements of thermal radiation from magnetic white dwarf (MWD) stars have been proposed as a probe of axion-photon mixing. The radiation leaving the surface of the MWD is unpolarized, but if low-mass axions exist then…
The characteristic axion couplings could be generated via effective couplings between the Standard Model (SM) fermions to a pseudo-Goldstone from a high-scale $U(1)$ Peccei-Quinn (PQ) symmetry breaking. Assuming that the UV-induced…
The quantum correlation of octave-spanning time-energy entangled bi-photons can be as short as a single optical cycle. Many experiments designed to explore and exploit this correlation require a uniform spectral phase (transform-limited)…
The presence of axions introduces new diagrams at one-loop order to the two-photon decays of the neutral pion through axion-pion mixing. In this work, we calculate this correction, missing in all current calculations, in the framework of…
We give detailed predictions for the spectral signatures arising from photon-particle oscillations in astrophysical objects. The calculations include quantum electrodynamic effects as well as those due to active relativistic plasma. We show…