Volume 367 - XXIX International Symposium on Lepton Photon Interactions at High Energies (LeptonPhoton2019) - Parallel Sessions
New results from the DANSS experiment
Y. Shitov
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Pre-published on: 2019 November 21
Published on:
Abstract
The DANSS is a highly segmented m$^3$ $\bar{\nu}$-spectrometer aimed
to search for SBL sterile neutrino oscillations in the reactor sector,
as well as to solve applied tasks of monitoring the power and fuel
composition of a nuclear reactor~\cite{Alekseev:2018efk}. The detector
measures the $\bar{\nu}$-spectrum by the IBD method from an industrial
nuclear reactor (3.1 GW$_{th}$, KNNP, Rusia) at distances 10.7-12.7~m
from the core using a mobile platform. The search for sterile
neutrino oscillations is carried out through the analysis of the
bin-per-bin ratios of the positron energy spectra collected at
different distances from the reactor. This relative method is free
from systematic errors associated with the calculation of the reactor
antineutrino spectra and detector efficiency.

The new results of the DANSS experiment are presented here based on
more than 2.1 million events collected in 2016-2019 (2.4-fold increase
over published data~\cite{Alekseev:2018efk}). With the current full
data set we do not have a statistically significant sign of the
sterile neutrino oscillations excluding further the large and
interesting portion of the $3\nu + 1\nu$ model phase space. The
DANSS's abilities to measure nuclear fuel composition and to monitor
reactor power at high precision (with 1.5/0.5\%
statistical/systematical uncertainties reached in 2 days of exposure) in
long-term scale (during 17 months) have been also undoubtedly
demonstrated.
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