Related papers: Axion-electron decoupling in nucleophobic axion mo…
Preferred axion models are minimal realizations of the Peccei-Quinn solution to the strong CP problem while providing a dark matter candidate. These models invoke new heavy quarks that interact strongly with the Standard Model bringing them…
We present a mechanism wherein the QCD axion coupling to nucleons, photons, or electrons, can be enhanced selectively without increasing the axion mass. We focus in particular on the axion-nucleon couplings, that are generally considered to…
We present new constraints on the couplings of axions and more generic axion-like particles using data from the EDELWEISS-II experiment. The EDELWEISS experiment, located at the Underground Laboratory of Modane, primarily aims at the direct…
Hot axions are produced in the early Universe via their interactions with Standard Model particles, contributing to dark radiation commonly parameterized as $\Delta N_{\text{eff}}$. In standard QCD axion benchmark models, this contribution…
We reanalyze the cosmological constraints on the existence of a net universal lepton asymmetry and neutrino degeneracy. We show that neutrinos can begin to decouple at higher temperatures than previous estimates due to several corrections…
The energy loss rate of a magnetized electron gas emitting axions a due to the process $e^- \to e^- +a$ is derived for arbitrary magnetic field strength B. Requiring that for a strongly magnetized neutron star the axion luminosity is…
We propose a class of axion models with generation dependent Peccei-Quinn charges for the known fermions that allow to suppress the axion couplings to nucleons and electrons. Astrophysical limits are thus relaxed, allowing for axion masses…
Direct Chandra observations of a surface temperature of isolated neutron star in Cassiopeia A (Cas A NS) and its cooling scenario which has been recently simultaneously suggested by several scientific teams put stringent constraints on…
We systematically calculate the axion-photon coupling for non-minimal DFSZ models. Thereby we can classify every calculated model and study the resulting distributions, relevant for axion experiments like haloscopes, helioscopes or…
The high temperature and electron degeneracy attained during a supernova allow for the formation of a large muon abundance within the core of the resulting proto-neutron star. If new pseudoscalar degrees of freedom have large couplings to…
We revisit the joint constraints in the mixed hot dark matter scenario in which both thermally produced QCD axions and relic neutrinos are present. Upon recomputing the cosmological axion abundance via recent advances in the literature, we…
Using recent supernova models, I revisit the Supernova 1987a constraints on scalar/pseudoscalar Axion-Like-Particles (ALPs). On the basis of the neutrino detections, the luminosity of ALPs must be $\lesssim 5\times10^{52} \,\mathrm{erg}/s$…
Axion models with generation-dependent Peccei-Quinn charges can lead to flavor-changing neutral currents, thus motivating QCD axion searches at precision flavor experiments. We rigorously derive limits on the most general effective…
It has been recently pointed out that in certain axion models it is possible to suppress simultaneously both the axion couplings to nucleons and electrons, realising the so-called astrophobic axion scenarios, wherein the tight bounds from…
Flaton models of Peccei-Quinn symmetry have good particle physics motivation, and are likely to cause thermal inflation leading to a well-defined cosmology. They can solve the $\mu$ problem, and generate viable neutrino masses. Canonical…
In models with an extended Higgs sector there exists an alignment limit, in which the lightest CP-even Higgs boson mimics the Standard Model Higgs. The alignment limit is commonly associated with the decoupling limit, where all non-standard…
We discuss a phenomenological model that extends the minimal supersymmetric standard model to contain axions and their supersymmetric partner, the axino. In the supersymmetric DFSZ axion model, the axino has tree level couplings to the…
A finite axion-nucleon coupling enables the production of axions in stellar environments via the thermal excitation and subsequent de-excitation of the $^{57}$Fe isotope. Given its low-lying excited state at 14.4 keV, $^{57}$Fe can be…
We explore consequences of the idea that the cooling speed of white dwarfs can be interpreted in terms of axion emission. In this case the Yukawa coupling to electrons has to be g_{ae} 10^-13, corresponding to an axion mass of a few meV.…
Axion production from astrophysical bodies is a topic in continuous development, because of theoretical progress in the estimate of stellar emission rates and, especially, because of improved stellar observations. We carry out a…