Diffuse neutrino flux measurements with the Baikal-GVD neutrino telescope

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 3.05u. 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 yastro = 2.58 thorn 0.27 -0.33 and the flux normalization Oastro = 3.04 thorn 1.52 -1.21 per one flavor at 100 TeV.

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We report the first observation of the diffuse cosmic neutrino flux with the Baikal-GVD neutrino telescope. An excess of events over the expected atmospheric background is observed using cascadelike events collected by Baikal-GVD in 2018-2021, which 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 best-fit parameter values are found to be: the spectral index yastro = 2.58±0.27-0.33 and the flux normalization Oastro = 3.04±1.52-1.21 per one flavor at 100 TeV.