Conveners
Neutrinos III
- Ahmed Ismail
We present a scenario where the smallness of neutrino masses is related to a global symmetry violation by quantum gravitational effects. We propose a setup that leads to axion particles which decay into neutrinos. This setup could be probed via cosmological measurements and may help explain the Hubble parameter tension. Depending on the details, the scenario could provide axion dark matter candidates.
keV-scale gauge-singlet fermions, when allowed to mix with the active neutrinos, are elegant dark matter (DM) candidates. They are produced in the early Universe via the Dodelson-Widrow mechanism and can be detected as they decay very slowly, emitting x-rays. In the absence of new physics, this hypothesis is virtually ruled out by astrophysical observations. Here, we show that new interactions...
I will introduce arguably the simplest extension of the Standard Model which leads to renormalizable long-range vector-mediated neutrino self-interactions. This gives rise to four-neutrino intractions with a strength similar to what has been discussed to resolve the cosmological hubble tension, whithout conflicting with other data. The extended gauge and scalar sector leads to signatures in...
We discuss the connection between the origin of neutrino masses and the properties of dark matter candidates in the context of gauge extensions of the Standard Model. We investigate minimal gauge theories for neutrino masses where the neutrinos are predicted to be Dirac or Majorana fermions. We find that the upper bound on the effective number of relativistic species provides the strongest...
Neutrinos can escape dense environments, otherwise opaque to photons, and travel cosmic distances unscathed by background radiation or magnetic fields. While ideal cosmic messengers, they present a unique opportunity to test physics beyond the Standard Model, especially dark matter. There is a distinct possibility that the principal portal through which the dark matter interacts with the...
IceCube has measured an astrophysical flux of neutrinos extending to 10 PeV. However, a guaranteed yet undetected flux of cosmogenic neutrinos caused by interactions of ultra-high energy cosmic rays with the cosmic microwave background remains elusive. Using the regeneration effect, we show that EeV tau neutrinos traversing the Earth cascade down in energy and emerge at O(PeV), a region where...
Neutrino signal from the next galactic supernova may carry in it imprints of the matter profile features that fall in the density range of ∼$10^3$ g/cm$^3$. The features in question include discontinuities and small-scale fluctuations, which are caused by shocks and turbulent mixing. A well-discussed example is the shockwave expanding through the envelope of the star, which reaches the...
