The optical module of Baikal-GVD

In April 2015, the first cluster of Baikal-GVD was deployed in Lake Baikal and put into operation. It comprises eight strings. Each string consists of 24 optical modules. An optical module is a detection element of Baikal-GVD; it includes a Hamamatsu R7081-100 photomultiplier tube with a high quantum sensitivity. We describe the design of the optical module, the front-end electronics, and the laboratory characterization and calibration.     

Deep inelastic neutrino interactions in the bubble chamber skat at 2–30 GeV

Data on inclusive deep inelastic neutrino interactions at 2–30 GeV are presented. Distributions in x, y and 〈Q²〉 dependence on neutrino energy are compared with quark-parton model predictions. The 〈Q²〉 dependence on energy has the form: 〈Q²〉 = (0.2 ± 0.1) + (0.25 ± 0.02) E_v.     

Measurement of the νμN total cross section at 2–30 GeV in a skat neutrino experiment

Data on the measurement of the v_μN total cross section at 2–30 GeV are presented. The observed behavior does not contradict a linear dependence on neutrino energy with slope S=0.73 ± 0.08.     

Preliminary results on SKAT neutrino experiment at 2–30 GeV

The data on inclusive deep inelastic neutrino scattering at 2–30 GeV were obtained with the bubble chamber SKAT. Distributions in q², x, y and mean q² dependence on neutrino energy are in agreement with quark parton model.     

Observation of possible production and decay of short-living heavy neutral particles in the SKAT neutrino experiment

In the SKAT bubble chamber neutrino experiment production of a short-living neutral particle with mass (1.4?m?2.5) GeV/c² and lifetime τ≈6×10^?12 s has been detected. The event may be interpreted as production and decay of the heavy lepton M⁰→μ^?+e⁺+ν_e with mass (1.4?m_M⁰?2.1) GeV/c². It might also be the production of a charmed particle D⁰→e⁺+τ^?+ν_e (D⁰→e⁺+π^?+ν_e) with mass 1.4?m_D⁰?2.5) GeV/c² in a non-diagonal neutral current. The probability to interpret the event as other possible processes is very low.     

Neutrino signal at Baikal from dark matter in the Galactic Center

We discuss neutrinos originating from dark matter in the Galactic Center and present sensitivity of Baikal Gigaton Volume Detector to this signal.     

Search for High-Energy Neutrinos from GW170817 with the Baikal-GVD Neutrino Telescope

JETP Letters - The Advanced Laser Interferometer Gravitational-Wave Observatory and Advanced Virgo observatories recently discovered gravitational waves from a binary neutron star inspiral. A short...     

Dark matter constraints from an observation of dSphs and the LMC with the Baikal NT200

We have analyzed the neutrino events recoded in the deep-water neutrino experiment NT200 in Lake Baikal in five years of observations toward dark dwarf spheroidal galaxies (dSphs) in the southern hemisphere and the Large Magellanic Cloud (LMC). This analysis completes the series of works based on NT200 data in the search for a dark matter annihilation signal in astrophysical objects. We have found no significant excess in the number of observed events relative to the expected background from atmospheric neutrinos in all tested directions, in 22 dSphs and the LMC. For a sample of five selected dwarf galaxies we have performed a joint analysis of the data by the maximum likelihood method. We have obtained a correspondence of the observational data to the null hypothesis about the presence of only background events and established 90% confidence-level upper limits for the annihilation cross sections of dark matter particles with a mass from 30 GeV to 10 TeV in several annihilation channels both in the joint analysis of the selected sample of galaxies and in the analysis toward the LMC. The strongest constraints at a level of 7 × 10^–21 cm³ s^–1 have been obtained for the direction toward the LMC in the channel of annihilation into a pair of neutrinos.