Relic neutrino decay solution to the excess radio background

Abstract

The excess radio background detected by ARCADE 2 represents a puzzle within the standard cosmological model. There is no clear viable astrophysical solution, and therefore, it might indicate the presence of new physics. Radiative decays of a relic neutrino ${\nu }_i$ (either $i=1$, or $i=2$, or $i=3$) into a sterile neutrino ${\nu }_{\mathrm{s}}$, assumed to be quasi-degenerate, provide a solution that currently evades all constraints posed by different cosmological observations and reproduces very well the ARCADE 2 data. We find a very good fit to the ARCADE 2 data with best fit values ${\tau }_i=1.46\times 10^{21}\mathrm{s}$ and $\Delta m_i=4.0\times 10^{-5}\mathrm{eV}$, where ${\tau }_i$ is the lifetime and $\Delta m_i$ is the mass difference between the decaying active neutrino and the sterile neutrino. On the other hand, if relic neutrino decays do not explain ARCADE 2 data, then these place a stringent constraint $\Delta m_i^{3/2}{\tau }_i\gtrsim 2\times 10^{14}{\mathrm{eV}}^{3/2}\mathrm{s}$ in the range $1.4\times 10^{-5}\mathrm{eV}<\Delta m_i<2.5\times 10^{-4}\mathrm{eV}$. The solution also predicts a stronger 21 cm absorption global signal than the predicted one from the $\Lambda$CDM model, with a contrast brightness temperature $T_{21}=-238_{-20}^{+21}\mathrm{mK}$ ($99\%$ C.L.) at redshift $z\simeq 17$. This is in mild tension with the even stronger signal found by the EDGES collaboration, $T_{21}=-500_{-500}^{+200}\mathrm{mK}$, suggesting that this might have been overestimated, possibly receiving a contribution from some unidentified foreground source.

21 pages, 3 figures, 3 tables, v2: it matches version to be published in JCAP

References in corpus (24)

• Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
• Signature of Excess Radio Background in the 21-cm Global Signal and Power Spectrum
• Improved Constraints on the 21 cm EoR Power Spectrum and the X-Ray Heating of the IGM with HERA Phase I Observations
• Pseudo-Dirac Neutrinos in the New Standard Model
• Constraining Neutrino Masses, the Cosmological Constant and BSM Physics from the Weak Gravity Conjecture
• Spectral distortion constraints on photon injection from low-mass decaying particles
• Astrophysical Constraints from the SARAS3 non-detection of the Cosmic Dawn Sky-Averaged 21-cm Signal
• Discovering the Sky at the Longest wavelengths with a lunar orbit array
• The Deep Diffuse Extragalactic Radio Sky at 1.75 GHz
• Neutrino clustering in the Milky Way and beyond
• The role of soft photon injection and heating in 21 cm cosmology
• The Second Radio Synchrotron Background Workshop: Conference Summary and Report
• PRATUSH experiment concept and design overview
• A Bayesian Calibration Framework for EDGES
• Naturally Light Dirac and Pseudo-Dirac Neutrinos from Left-Right Symmetry
• SN1987A still shining: A Quest for Pseudo-Dirac Neutrinos
• Revisiting pseudo-Dirac neutrino scenario after recent solar neutrino data
• Can accreting primordial black holes explain the excess radio background?
• A Stimulating Explanation of the Extragalactic Radio Background
• Influence of local structure on relic neutrino abundances and anisotropies
• Constraining super-light sterile neutrinos at Borexino and KamLAND
• Cosmological origin of anomalous radio background
• A closer look at dark photon explanations of the excess radio background
• The optical system of the Tenerife Microwave Spectrometer: a window for observing the 10-20 GHz sky spectra

Cited by in corpus (4)

• The CosmoVerse White Paper: Addressing observational tensions in cosmology with systematics and fundamental physics
• Pseudo-Dirac Neutrinos and Relic Neutrino Matter Effect on the High-energy Neutrino Flavor Composition
• Primordial black holes as dark matter candidates: Multi-frequency constraints from cosmic radiation backgrounds
• Boomerang mechanism explaining the excess radio background