arXiv subjects

Miller MacDonald

Publications and source records attributed to Miller MacDonald.

3 recordsLinked to original sources

arXiv2025

Exploring New Propagation Scales With Galactic Neutrinos

The recent observation of high-energy Galactic neutrinos by IceCube allows for searches of new physics affecting neutrino propagation on scales of $O(10^9-10^{15})\,\mathrm{km/GeV}$ in distance over energy. We assess the sensitivity of upcoming measurements of Galactic neutrinos by IceCube and KM3NeT to such new phenomena. We focus on two scenarios: quasi-Dirac neutrinos and neutrino decays. In the quasi-Dirac scenario, we find that joint measurements by IceCube and KM3NeT are sensitive to the mass-squared differences $\delta m^2 \in \left(10^{-13.6}~\mathrm{eV^2}, 10^{-12.3}~\mathrm{eV^2}\right)$ at the $90\%$ confidence level. For neutrino decays, the same measurements are sensitive to mass over lifetime ratios $m / \tau > 10^{-12.8}~\mathrm{eV^2}$ at the same significance. Our results demonstrate that measurements of Galactic neutrinos by a global network of neutrino telescopes can probe signatures of neutrino mass models.

hep-ph↗

arXiv2025

The Milky Way is a Laboratory for New Ultra-long-baseline Neutrino Physics

The IceCube Neutrino Observatory recently published evidence for diffuse neutrino emission from the Galactic Plane at $4.5\sigma$ significance. This new source of astrophysical neutrinos provides an exciting laboratory for probing the nature of neutrino masses. In particular, extremely small mass splittings, such as those predicted by quasi-Dirac neutrino mass models, and finite neutrino lifetimes from neutrino decays, would induce effects on the spectra and flavor ratios of neutrinos with TeV-scale energies traversing kiloparsec-scale baselines. Using $\mathtt{TANDEM}$, an upcoming three dimensional galactic neutrino emission model, we explore the sensitivity of IceCube and KM3NeT/ARCA to these ultra-long-baseline phenomena. We find that a combined analysis would be sensitive to quasi-Dirac mass splittings $10^{-14.0}~\mathrm{eV^2} \lesssim \delta m^2 \lesssim 10^{11.6}~\mathrm{eV^2}$ and neutrino lifetimes $m / \tau \gtrsim 10^{-14.1}~\mathrm{eV^2}$ at $> 1\sigma$, both regions constituting as-yet unexplored parameter space. Our results demonstrate the potential that astrophysical neutrino sources and global neutrino telescope networks have in probing new regions of exotic neutrino mass models.

hep-ph↗

arXiv2024

The Unknowns of the Diffuse Supernova Neutrino Background Hinder New Physics Searches

Neutrinos traveling over cosmic distances are ideal probes of new physics. We leverage on the approaching detection of the diffuse supernova neutrino background (DSNB) to explore whether, if the DSNB showed departures from theoretical predictions, we could attribute such modifications to new physics unequivocally. In order to do so, we focus on visible neutrino decay. Many of the signatures from neutrino decay are degenerate with astrophysical unknowns entering the DSNB modeling. Next generation neutrino observatories, such as Hyper-Kamiokande, JUNO, as well as DUNE, will set stringent limits on a neutrino lifetime over mass ratio $\tau/m \sim 10^{9}$-$10^{10}$ s eV$^{-1}$ at $90\%$ C.L., if astrophysical uncertainties and detector backgrounds were to be fully under control. However, if the lightest neutrino is almost massless and the neutrino mass ordering is normal, constraining visible decay will not be realistically possible in the coming few decades. We also assess the challenges of distinguishing among different new physics scenarios (such as visible decay, invisible decay, and quasi-Dirac neutrinos), all leading up to similar signatures in the DSNB. This work shows that the DSNB potential for probing new physics strongly depends on an improved understanding of the experimental backgrounds at next generation neutrino observatories as well as progress in the DSNB modeling.

astro-ph.HE↗