2-5 October 2017
Hotel Intourist Kolomenskoye 4*
Europe/Moscow timezone

Experiment Neutrino-4 on search for sterile neutrino at SM-3 reactor

4 Oct 2017, 09:45
15m
Petrovsky hall (Hotel Intourist Kolomenskoye 4*)

Petrovsky hall

Hotel Intourist Kolomenskoye 4*

Kashyrskoye shosse, 39B, Moscow, Russia, 115409
Plenary/section talk Neutrino and astroparticle physics Neutrino and Astroparticle Physics - 2

Speaker

Mr. Rudolf Samoilov (PNPI)

Description

The experiment "Neutrino-4" started in 2014 on a model, then it was continued on a full-scale detector, and now, for the first time in the world, has provided the measurement result on dependence of the flux of reactor antineutrinos on the distance of 6-12 meters from the center of the reactor. One of the main problems is the correlated background from fast neutrons caused by space radiation. Attempts to suppress the background of fast neutrons by sectioning the detector have given the required result. The relation of effect/background has improved from 0.3 to 0.6. As a result, measurements of the difference in the counting rate of neutrino-like events (reactor ON-reactor OFF) for a full-scale detector have been obtained as dependence on distance from the reactor center. Besides, the spectrum of prompt signals of neutrino-like events has been presented. The fit of experimental dependence with the law $1/L^{2}$ , however, does not give an absolutely satisfactory result. The goodness of that fit is a little more than 10%, i.e. the confidence level is about 90% in deviation from the law $1/L^{2} (1.64\sigma)$. The similar situation arises in the analysis of spectrum dependence of prompt signals, which is also 90% of confidence level. Of course, the joint deviation, demanding identical parameters $\Delta m_{14}^{2} =0.7 \div 0.8~eV ^{2}$ and $sin^{2}(2\theta_{14})$=$0.10\div0.15$, increases the confidence level up to about 95% $(2\sigma)$. But it is still not enough for making statements on observation of the phenomenon, especially, such an important one as oscillations in a sterile state. At last, it is also impossible now to exclude possibility of influence of systematic errors on the final experimental result. Therefore, in future we would like to concentrate efforts on increase in accuracy of the experiment and control of possible systematic errors.

Primary authors

Prof. Anatolii Serebrov (PNPI NRC KI) Mr. Rudolf Samoilov (PNPI) Mr. Vladimir Ivochkin (PNPI NRC KI)

Co-authors

Dr. Alexey Fomin (PNPI NRC KI)

Presentation Materials

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