HET Seminar

Abstract: Core-collapse supernovae are among the most spectacular and efficient neutrino factories known so far. Detection of these neutrinos allows us to probe physics in extreme conditions not accessible on Earth. But so far, even with the detection of about twenty electron antineutrinos from SN 1987 A, we are yet to test even the most basic prediction about the neutrino emission, i.e., different neutrino flavors produced during the collapse share a comparable amount of the released energy. Existing detectors can register significantly more neutrinos of all flavors from the closeby core-collapse supernova and test this assumption. Unfortunately, this extreme phenomenon rarely occurs in our galaxy and its vicinity, only a few times per century.

What is more, while the multichannel detection of the next nearby supernova undoubtedly will allow us to measure and infer certain pieces of information, these will be solely about a single star. Theoretically, we expect a lot of common features, but nature may surprise us. Because of that, it is essential to observe neutrinos from multiple supernova events – the diffuse supernova neutrino background (DSNB).

The Super-Kamiokande (SK) detector achieved the most stringent upper limit on the electron antineutrino component of the DSNB. This limit is only a factor of 2-3 above most of the theoretical predictions. In addition, SK is now enriched with gadolinium which will help to reduce backgrounds for the DSNB search and most probably lead to the detection within the near future. The electron neutrino component of the DSNB has a ten times weaker upper limit than the electron antineutrino component. But with the upcoming Deep Underground Neutrino Experiment (DUNE), the limit may change into observation. As impressive as it sounds, capturing the complete picture of the core-collapse supernova landscape and investigating new astrophysics or physics requires probing DSNB in all flavors. But the upper limits on the non-electron component of the DSNB (muon and tau neutrinos and antineutrinos) are approximately a thousand times weaker than the theoretical predictions.

In this talk, I will present how the large-scale direct dark matter detectors can help significantly tighten the upper limits on the non-electron component of DSNB. In addition, I will talk about plausible beyond the Standard Model scenarios, which could alter the non-electron neutrino emission from the core-collapse supernovae.