Lorentz Symmetry and High-Energy Neutrino Astronomy

The search of the violation of Lorentz symmetry, or Lorentz violation (LV), is an active research field. The effects of LV are expected to be very small, and special systems are often used to search it. High-energy astrophysical neutrinos offer a unique system to search signatures of LV, due to the three factors: high neutrino energy, long propagation distance, and the presence of quantum mechanical interference. In this brief review, we introduce tests of LV and summarize existing searches of LV, using atmospheric and astrophysical neutrinos.

Atmospheric neutrinos with the first detection units of KM3NeT/ARCA

The KM3NeT collaboration is constructing two deep-sea Cherenkov detectors in the Mediterranean Sea. The ARCA detector aims at TeV-PeV neutrino astronomy, while the ORCA detector is optimised for atmospheric neutrino oscillation studies at energies of a few GeV. In this contribution, an analysis of the data collected with the first deployed detection units of the ARCA detector is presented. A high-purity sample of atmospheric neutrinos is selected demonstrating the capability of the ARCA detector.

Progress in neutrino astronomy

The dream of observing our universe through neutrinos is rapidly becoming a reality. More than three decades after the first observation of neutrinos from beyond our solar system associated with Supernova SN1987A, neutrino astronomy is in the midst of a revolution. Extraterrestrial neutrinos are now routinely detected, following the discovery of a high-energy diffuse astrophysical neutrino flux in 2013. The detection of a high-energy neutrino in coincidence with a flaring blazar in 2017 has brought the field rapidly into the multi-messenger science era. The latest developments in the field of neutrino astronomy are reviewed and prospects with current and future detectors discussed. Particular emphasis is put on domestic programs in neutrino astronomy and the possibility to construct a large neutrino observatory in Korea.

High-Energy Neutrino Astronomy—Baikal-GVD Neutrino Telescope in Lake Baikal

High-energy neutrino astronomy is a fascinating new field of research, rapidly developing over recent years. It opens a new observation window on the most violent processes in the universe, fitting very well to the concept of multi-messenger astronomy. This may be exemplified by the recent discovery of the high-energy neutrino emissions from the γ-ray loud blazar TXS 0506+056. Constraining astrophysical neutrino fluxes can also help to understand the long-standing mystery of the origin of the ultra-high energy cosmic rays. Astronomical studies of high-energy neutrinos are carried out by large-scale next-generation neutrino telescopes located in different regions of the world, forming a global network of complementary detectors. The Baikal-GVD, being currently the largest neutrino telescope in the Northern Hemisphere and still growing up, is an important constituent of this network. This paper briefly reviews working principles, analysis methods, and some selected results of the Baikal-GVD neutrino telescope.