There is a vast potential in using the measurement of the flavor composition of high-energy (TeV-PeV) astrophysical neutrinos to test astrophysics and fundamental physics. But there is also plenty of uncertainty in the prediction of the allowed flavor composition at Earth, due to the uncertainties in the mixing parameters, and in the measurement of flavor composition in neutrino telescopes. In other words, flavor is a powerful tool, but it needs sharpening.
In our latest paper, we show that in the next 20 years, flavor will become the sharp tool it was always meant to be, thanks to new oscillation experiments and new neutrino telescopes:
The Future of High-Energy Astrophysical Neutrino Flavor Measurements Ningqiang Song, Shirley Weishi Li, Carlos A. Argüelles, Mauricio Bustamante, Aaron C. Vincent https://arxiv.org/abs/2012.12893
By 2040, we will be able to use flavor composition by itself to identify the production mechanism of high-energy astrophysical neutrinos:
The big POEMMA paper is finally out! It contains the science case, goals, and design of POEMMA, a twin-satellite experiment to detect the fluorescence and Cherenkov emission from extensive air showers triggered by ultra-high-energy cosmic rays and neutrinos in the atmosphere.
If the three active neutrinos mix with a sterile one, i.e., in 3+1 scenarios, they may modify the flavor composition of high-energy astrophysical neutrinos. We analytically derived boundaries in flavor space to avoid having to sample over unknown mixing and help boost searches for new physics (we provided them in nice downloadable data tables, too):
Flavors of Astrophysical Neutrinos with Active-Sterile Mixing Markus Ahlers, Mauricio Bustamante, Niels Gustav Nortvig Willesen https://arxiv.org/abs/2009.01253
The solid lines are the new 3+1 boundaries, computed for the three benchmark production scenarios (three different colors), compared to the boundaries that we computed for three-flavor mixing (dashed lines) in our earlier paper (1810.00893):
Where are the IceCube high-energy astrophysical neutrinos coming from? We don’t know yet! But if the neutrino sources harbor large magnetic fields, then maybe they will leave imprints (due to synchrotron radiation) on the neutrino flux. We looked for these imprints in public IceCube data:
The deadline for submission of letters of interest (LoIs) for the US Snowmass 2021 process was Monday, August 31. There were ~1600 LoIs submitted and all of them can be found here: https://snowmass21.org/loi .
I was personally involved in or led a few:
Cosmic Neutrino Probes of Fundamental Physics [pdf]
To place my new limts, I put to practice a proposal that we published earlier (1610.02096), that uses the observation of the Glashow resonance in IceCube, at a few PeV, as evidence of the survival of nu_1 and nu_2.
I base our present-day results on the observation of the first Glashow resonance candidate by IceCube. For nu_2, the limit on the lifetime is the best one to date. For nu_1, it is comparable to the best one to date, coming from solar neutrinos. The limits quickly improve with just a handful more of Glashow resonances observed.
Recently I was interviewed by El Comercio, the largest national newspaper in Perú, about neutrinos, particles physics, and my Villum Young Investigator grant. The interview appeared online and in print form on February 22, 2020. Here is a link to the online version (in Spanish):