Related papers: Cosmological bounds on pseudo Nambu-Goldstone boso…
A pseudo Nambu-Goldstone boson (pNGB) is a natural candidate of dark matter in that it avoids the severe direct detection bounds. We show in this paper that the pNGB has another different and interesting face with a higher symmetry breaking…
Non-supersymmetric Grand Unified $SO(10)\times U(1)_{\rm PQ}$ models have all the ingredients to solve several fundamental problems of particle physics and cosmology -- neutrino masses and mixing, baryogenesis, the non-observation of strong…
We have derived new bounds on the relativistic energy density in the Universe from cosmic microwave background (CMB), large scale structure (LSS), and type Ia supernova (SNI-a) observations. In terms of the effective number of neutrino…
We investigate the possible parametric growth of photon amplitudes in a background of axion-like particle (ALP) dark matter. The observed extragalactic background radiation limits the allowed enhancement effect. We derive the resulting…
Measuring spectral distortions of the cosmic microwave background (CMB) is attracting considerable attention as a probe of high energy particle physics in the cosmological context, since PIXIE and PRISM have recently been proposed. In this…
It has been recently claimed by two different groups that the spectral modulation observed in gamma rays from Galactic pulsars and supernova remnants can be due to conversion of photons into ultra-light axion-like-particles (ALPs) in…
Current LEP data on rare $Z$ decays constrain nonminimal technicolor models that contain light neutral pseudo-Nambu-Goldstone bosons ($P^a$). We discuss the production and decay of such particles, and show how LEP data on…
Axionlike particles (ALPs) are hypothetical light (sub-eV) bosons predicted in some extensions of the Standard Model of particle physics. In astrophysical environments comprising high-energy gamma rays and turbulent magnetic fields, the…
According to the standard models of particle physics and cosmology, there should be a background of cosmic neutrinos in the present Universe, similar to the cosmic microwave photon background. The weakness of the weak interactions renders…
Bounds are derived on the axion-like particle (ALP) to two-photon coupling in the mass range $2.65-5.27$ eV. The bounds are obtained by searching for the signal from ALP decay in the Multi Unit Spectroscopic Explorer (MUSE) observations of…
One of the most powerful probes of new physics is the polarized Cosmic Microwave Background (CMB). The detection of a nonzero polarization angle rotation between the CMB surface of last scattering and today could provide evidence of…
Neutrino masses arising from the spontaneous violation of ungauged lepton-number are accompanied by a physical Goldstone boson, generically called Majoron. In the high-density supernova medium the effects of Majoron-emitting neutrino decays…
We provide a comprehensive analysis of the phenomenology of axion-like particles (ALPs) produced in core-collapse supernovae (ccSNe) through interactions with electrons and muons, both of which have a non-negligible abundance in the SN…
Pseudo Nambu-Goldstone bosons (pNGBs) are naturally light spin-zero particles, which can be interesting dark matter (DM) candidates. We study the phenomenology of a pNGB theta associated with an approximate symmetry of the neutrino seesaw…
If the Universe underwent a cosmic phase transition, it may have left behind a network of cosmic strings. When these strings arise from the breaking of a gauge symmetry, their decay produces a significant stochastic background of…
Persistent excesses in the spectra of gamma rays from the galactic center and cosmic ray antiprotons can be explained by dark matter of mass $50\sim 65$\,GeV annihilating into $b$ quarks, but this is typically hard to reconcile with direct…
Cosmological constraints on the sum of neutrino masses and on the effective number of neutrino species in standard and non-standard scenarios are computed using the most recent available cosmological data. Our cosmological data sets include…
An analysis is given of interacting dark energy and dark matter where the dark energy is assumed to be an ultralight axionic field with a pseudo-Nambu-Goldstone Boson potential which is in general a superposition of $N$ number of cosine…
Studies of axion-like particles (ALPs) commonly focus on a single type of interaction, for example couplings only to photons. Most ALP models however predict correlations between different couplings, which change the phenomenology in…
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…