Diffuse neutrino flux measurements with the Baikal-GVD neutrino telescope

V A Allakhverdyan ,R Dvornický,L Fajt,E Eckerová,D Seitova,A Khatun,F Šimkovic,I Štekl,V Nazari,V Y Dik ,M.v Kruglov ,М Н Сороковиков ,А Р Гафаров ,V.f Kulepov ,К.г Кебкал ,G Safronov ,K V Konischev ,V M Aynutdinov ,Т Гресс ,Zh.-A.m Dzhilkibaev ,Р Р Миргазов ,E Khramov ,M.b Milenin ,I V Borina ,K.v Golubkov ,V.d Rushay ,Н М Буднев ,И А Белолаптиков ,A N Dyachok ,V K Kebkal ,Д П Петухов ,Y M Malyshkin ,M.d Shelepov ,А В Коробченко ,Z Bardаčová ,B A Shaybonov ,Eugene V Ryabov ,А В Скурихин ,A P Stromakov ,M.m Kolbin ,M.i Rozanov ,A.e Sirenko ,В А Кожин ,A.v Avrorin ,T V Elzhov ,A.g Solovjev ,Y V Yablokova ,G V Domogatsky ,D Naumov ,А П Кошечкин ,А.d Avrorin ,В А Таболенко ,E N Pliskovsky ,А А Дорошенко ,O V Suvorova ,N.s Gorshkov ,D Zaborov

doi:10.1103/physrevd.107.042005

Abstract

We report on the first observation of the diffuse cosmic neutrino flux with the Baikal-GVD neutrino telescope. Using cascadelike events collected by Baikal-GVD in 2018–2021, a significant excess of events over the expected atmospheric background is observed. This excess is consistent with the high-energy diffuse cosmic neutrino flux observed by IceCube. The null cosmic flux assumption is rejected with a significance of 3.05σ. Assuming a single power law model of the astrophysical neutrino flux with identical contribution from each neutrino flavor, the following best-fit parameter values are found: the spectral index γastro=2.58−0.33+0.27 and the flux normalization ϕastro=3.04−1.21+1.52 per one flavor at 100 TeV.Received 25 November 2022Accepted 10 January 2023DOI:https://doi.org/10.1103/PhysRevD.107.042005© 2023 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasNuclear astrophysicsNuclear Physics

Full Text