scholarly journals Sterile neutrinos and the global reactor antineutrino dataset

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Jeffrey M. Berryman ◽  
Patrick Huber
Keyword(s):  
Open Source Software ◽  
Sterile Neutrino ◽  
Statistical Interpretation ◽  
Spectral Ratios ◽  
Sterile Neutrinos ◽  
Reactor Antineutrino ◽  
Inverse Beta Decay ◽  
Antineutrino Flux ◽  
Flux Model ◽  
Tool Set

Abstract We present results from global fits to the available reactor antineutrino dataset, as of Fall 2019, to determine the global preference for a fourth, sterile neutrino. We have separately considered experiments that measure the integrated inverse-beta decay (IBD) rate from those that measure the energy spectrum of IBD events at one or more locations. The evidence that we infer from rate measurements varies between ≲ 3σ and negligible depending on the reactor antineutrino flux model employed. Moreover, we find that spectral ratios ostensibly imply ≳ 3σ evidence, consistent with previous work, though these measurements are known to be plagued by issues related to statistical interpretation; these results should therefore be viewed cautiously. The software used is the newly developed GLoBESfit tool set which is based on the publicly available GLoBES framework and will be released as open-source software.

scholarly journals New results from the DANSS experiment

2020 ◽  
Vol 35 (34n35) ◽  
pp. 2044015
Author(s):  
Nataliya Skrobova
Keyword(s):  
Nuclear Power ◽  
Sterile Neutrino ◽  
Reactor Core ◽  
Detector Efficiency ◽  
Sterile Neutrinos ◽  
Inverse Beta Decay ◽  
Systematic Uncertainties ◽  
Interesting Part ◽  
Raster Scan ◽  
Kalinin Nuclear Power Plant

We present new results of the DANSS experiment on the searches for sterile neutrinos. They are based on more than 2 million of inverse beta decay events collected at 10.7 m, 11.7 m and 12.7 m from the reactor core of the 3.1 GW Kalinin Nuclear Power Plant in Russia. This data sample is 2.4 times larger than the data sample in the previous DANSS publication. The search for the sterile neutrinos is performed using the ratio of [Formula: see text] spectra at two distances. This method is very robust against systematic uncertainties in the [Formula: see text] spectrum and the detector efficiency. We do not see any statistically significant sign for the [Formula: see text] oscillations. This allows us to exclude further a large and interesting part of the sterile neutrino parameter space. A Gaussian CL[Formula: see text] method was used to obtain exclusion areas. This method is more conservative than a Raster Scan method.

scholarly journals Evolution of the Reactor Antineutrino Flux and Spectrum at Daya Bay

2017 ◽  
Vol 118 (25) ◽  
Author(s):  
F. P. An ◽  
A. B. Balantekin ◽  
H. R. Band ◽  
M. Bishai ◽  
S. Blyth ◽  
...  
Keyword(s):  
Daya Bay ◽  
Reactor Antineutrino ◽  
Antineutrino Flux

scholarly journals Statistical interpretation of sterile neutrino oscillation searches at reactors

2021 ◽  
Vol 81 (1) ◽  
Author(s):  
Pilar Coloma ◽  
Patrick Huber ◽  
Thomas Schwetz
Keyword(s):  
Neutrino Oscillation ◽  
Sterile Neutrino ◽  
Statistical Significance ◽  
Statistical Interpretation ◽  
Actual Distribution ◽  
Mixing Angle ◽  
Log Likelihood ◽  
Reactor Neutrino ◽  
Neutrino Experiments ◽  
Experimental Effort

AbstractA considerable experimental effort is currently under way to test the persistent hints for oscillations due to an eV-scale sterile neutrino in the data of various reactor neutrino experiments. The assessment of the statistical significance of these hints is usually based on Wilks’ theorem, whereby the assumption is made that the log-likelihood is $$\chi ^2$$ χ 2 -distributed. However, it is well known that the preconditions for the validity of Wilks’ theorem are not fulfilled for neutrino oscillation experiments. In this work we derive a simple asymptotic form of the actual distribution of the log-likelihood based on reinterpreting the problem as fitting white Gaussian noise. From this formalism we show that, even in the absence of a sterile neutrino, the expectation value for the maximum likelihood estimate of the mixing angle remains non-zero with attendant large values of the log-likelihood. Our analytical results are then confirmed by numerical simulations of a toy reactor experiment. Finally, we apply this framework to the data of the Neutrino-4 experiment and show that the null hypothesis of no-oscillation is rejected at the 2.6 $$\sigma $$ σ level, compared to 3.2 $$\sigma $$ σ obtained under the assumption that Wilks’ theorem applies.

scholarly journals Searches for sterile neutrinos at the DANSS experiment

2019 ◽  
Vol 219 ◽  
pp. 08002
Author(s):  
Mark Shirchenko ◽  
Nataliya Skrobova
Keyword(s):  
Nuclear Power ◽  
Plastic Scintillator ◽  
Reactor Core ◽  
Sterile Neutrinos ◽  
Positron Energy ◽  
Inverse Beta Decay ◽  
Cosmic Background ◽  
Wide Range ◽  
Reactor Building ◽  
On Line

DANSS is a highly segmented 1 m3 plastic scintillator detector. The DANSS detector is placed under an industrial 3.1 GWth reactor of the Kalinin Nuclear Power Plant 350 km NW from Moscow. The distance to the core is varied on-line from 10.7 m to 12.7 m. The reactor building provides about 50 m water-equivalent shielding against the cosmic background. DANSS detects almost 5000 νe per day at the closest position with the cosmic background less than 3%. The inverse beta decay process is used to detect νe. Sterile neutrinos are searched for assuming the 4ν model (3 active and 1 sterile ν). The exclusion area in the Δm142,sin22θ14 plane is obtained using a ratio of positron energy spectra collected at different distances. Therefore results do not depend on the shape and normalization of the reactor νe spectrum nor the detector efficiency. Results are based on 966 thousand antineutrino events collected at three different distances from the reactor core. The excluded area covers a wide range of the sterile neutrino parameters down to sin22θ14 < 0.01 in the most sensitive region.

scholarly journals IceCube Sterile Neutrino Searches

2019 ◽  
Vol 207 ◽  
pp. 04005 ◽  
Author(s):  
B. J. P. Jones
Keyword(s):  
Large Volume ◽  
Sterile Neutrino ◽  
Large Mass ◽  
Neutrino Telescope ◽  
Muon Neutrino ◽  
Sterile Neutrinos ◽  
Short Baseline ◽  
Mixing Angles ◽  
Neutrino Telescopes ◽  
Ongoing Work

Anomalies in short baseline experiments have been interpreted as evidence for additional neutrino mass states with large mass splittings from the known, active flavors. This explanation mandates a corresponding signature in the muon neutrino disappearance channel, which has yet to be observed. Searches for muon neutrino disappearance at the IceCube neutrino telescope presently provide the strongest limits in the space of mixing angles for eVscale sterile neutrinos. This proceeding for the Very Large Volume Neutrino Telescopes (VLVnT) Workshop summarizes the IceCube analyses that have searched for sterile neutrinos and describes ongoing work toward enhanced, high-statistics sterile neutrino searches.

scholarly journals NEUTRINO SHORTCUTS IN SPACETIME

2012 ◽  
Vol 27 (21) ◽  
pp. 1250127 ◽  
Author(s):  
A. NICOLAIDIS
Keyword(s):  
Extra Dimensions ◽  
Sterile Neutrino ◽  
Large Extra Dimensions ◽  
Resonance Phenomenon ◽  
Neutrino Beam ◽  
Strong Mixing ◽  
Sterile Neutrinos ◽  
Large Extra Dimension ◽  
Long Baseline ◽  
Experimental Side

Theories with large extra dimensions may be tested using sterile neutrinos living in the bulk. A bulk neutrino can mix with a flavor neutrino localized in the brane leading to unconventional patterns of neutrino oscillations. A resonance phenomenon, strong mixing between the flavor and the sterile neutrino, allows one to determine the radius of the large extra dimension. If our brane is curved, then the sterile neutrino can take a shortcut through the bulk, leading to an apparent superluminal neutrino speed. The amount of "superluminality" is directly connected to parameters determining the shape of the brane. On the experimental side, we suggest that a long baseline neutrino beam from CERN to NESTOR neutrino telescope will help to clarify these important issues.

scholarly journals MODEL INDEPENDENT CONSTRAINTS ON NON-ELECTRONIC FLAVORS IN THE SOLAR BORON NEUTRINO FLUX

2006 ◽  
Vol 21 (22) ◽  
pp. 1761-1768 ◽  
Author(s):  
S. DEV ◽  
SANJEEV KUMAR ◽  
SURENDER VERMA
Keyword(s):  
General Model ◽  
Sterile Neutrino ◽  
Neutrino Flux ◽  
Flux Measurement ◽  
Data Set ◽  
The Earth ◽  
Independent Analysis ◽  
Antineutrino Flux ◽  
Model Independent ◽  
Salt Phase

We perform the most general model-independent analysis of the latest 391-Day Salt Phase SNO Data Set incorporating the super-Kamiokande ES flux measurement and obtain bounds on the antineutrino and sterile neutrino flux in the solar 8 B neutrino flux reaching the detectors on the earth. The muon/tauon antineutrino flux is found to be disallowed at 1.4σ C.L. The sterile flux is found to be nonzero at about 1.26 standard deviations.

Sign in / Sign up

Export Citation Format

Share Document