39 research outputs found
Search for sterile neutrinos at the DANSS experiment
DANSS is a highly segmented 1~m plastic scintillator detector. Its 2500
one meter long scintillator strips have a Gd-loaded reflective cover. The DANSS
detector is placed under an industrial 3.1~ 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 per day at the closest position with the cosmic
background less than 3. The inverse beta decay process is used to detect
. Sterile neutrinos are searched for assuming the model
(3 active and 1 sterile ). The exclusion area in the 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 spectrum, as well
as on the detector efficiency. Results are based on 966 thousand antineutrino
events collected at 3 distances from the reactor core. The excluded area covers
a wide range of the sterile neutrino parameters up to
in the most sensitive region.Comment: 10 pages, 13 figures, version accepted for publicatio
Measurements of the and -induced Coherent Charged Pion Production Cross Sections on by the T2K experiment
We report an updated measurement of the -induced, and the first
measurement of the -induced coherent charged pion production
cross section on nuclei in the T2K experiment. This is measured in a
restricted region of the final-state phase space for which
GeV, and , and at a mean
(anti)neutrino energy of 0.85 GeV using the T2K near detector. The measured
CC coherent pion production flux-averaged cross section on
is . The new measurement
of the -induced cross section on is . The results are compatible with both the NEUT
5.4.0 Berger-Sehgal (2009) and GENIE 2.8.0 Rein-Sehgal (2007) model
predictions
Measurements of the νμ and ν¯μ -induced coherent charged pion production cross sections on C12 by the T2K experiment
We report an updated measurement of the
ν
μ
-induced, and the first measurement of the
¯
ν
μ
-induced coherent charged pion production cross section on
12
C
nuclei in the Tokai-to-Kamioka experiment. This is measured in a restricted region of the final-state phase space for which
p
μ
,
π
>
0.2
GeV
,
cos
(
θ
μ
)
>
0.8
and
cos
(
θ
π
)
>
0.6
, and at a mean (anti)neutrino energy of 0.85 GeV using the T2K near detector. The measured
ν
μ
charged current coherent pion production flux-averaged cross section on
12
C
is
(
2.98
±
0.37
(
stat
)
±
0.31
(
syst
)
+
0.49
−
0.00
(
Q
2
model
)
)
×
10
−
40
cm
2
. The new measurement of the
¯
ν
μ
-induced cross section on
12
C
is
(
3.05
±
0.71
(
stat
)
±
0.39
(
syst
)
+
0.74
−
0.00
(
Q
2
model
)
)
×
10
−
40
cm
2
. The results are compatible with both the NEUT 5.4.0 Berger-Sehgal (2009) and GENIE 2.8.0 Rein-Sehgal (2007) model predictions
Construction status and prospects of the Hyper-Kamiokande project
The Hyper-Kamiokande project is a 258-kton Water Cherenkov together with a 1.3-MW high-intensity neutrino beam from the Japan Proton Accelerator Research Complex (J-PARC). The inner detector with 186-kton fiducial volume is viewed by 20-inch photomultiplier tubes (PMTs) and multi-PMT modules, and thereby provides state-of-the-art of Cherenkov ring reconstruction with thresholds in the range of few MeVs. The project is expected to lead to precision neutrino oscillation studies, especially neutrino CP violation, nucleon decay searches, and low energy neutrino astronomy. In 2020, the project was officially approved and construction of the far detector was started at Kamioka. In 2021, the excavation of the access tunnel and initial mass production of the newly developed 20-inch PMTs was also started. In this paper, we present a basic overview of the project and the latest updates on the construction status of the project, which is expected to commence operation in 2027
Prospects for neutrino astrophysics with Hyper-Kamiokande
Hyper-Kamiokande is a multi-purpose next generation neutrino experiment. The detector is a two-layered cylindrical shape ultra-pure water tank, with its height of 64 m and diameter of 71 m. The inner detector will be surrounded by tens of thousands of twenty-inch photosensors and multi-PMT modules to detect water Cherenkov radiation due to the charged particles and provide our fiducial volume of 188 kt. This detection technique is established by Kamiokande and Super-Kamiokande. As the successor of these experiments, Hyper-K will be located deep underground, 600 m below Mt. Tochibora at Kamioka in Japan to reduce cosmic-ray backgrounds. Besides our physics program with accelerator neutrino, atmospheric neutrino and proton decay, neutrino astrophysics is an important research topic for Hyper-K. With its fruitful physics research programs, Hyper-K will play a critical role in the next neutrino physics frontier. It will also provide important information via astrophysical neutrino measurements, i.e., solar neutrino, supernova burst neutrinos and supernova relic neutrino. Here, we will discuss the physics potential of Hyper-K neutrino astrophysics
Observation of the temperature and barometric effects on the cosmic muon flux by the DANSS detector
The DANSS detector (Alekseev et al. in JINST 11:P11011, 2016) is located directly below a commercial reactor core at the Kalinin Nuclear Power Plant. Such a position provides an overburden about 50 m.w.e. in vertical direction. In terms of the cosmic rays it occupies an intermediate position between surface and underground detectors. The sensitive volume of the detector is a cubic meter of plastic scintillator with fine segmentation and combined PMT and SiPM readout, surrounded by multilayer passive and active shielding. The detector can reconstruct muon tracks passing through its sensitive volume. The main physics goal of the DANSS experiment implies the antineutrino spectra measurements at various distances from the source. This is achieved by means of a lifting platform so that the data is taken in three positions – 10.9, 11.9 and 12.9 meters from the reactor core. The muon data were collected for nearly four calendar years. The overburden parameters and , as well as the temperature and barometric correlation coefficients are evaluated separately for the three detector positions and, in each position, in three ranges of the zenith angle – for nearly vertical muons with , for nearly horizontal muons with , and for the whole upper hemisphere
Application of the Duperier method to the analysis of the cosmic muon flux dependence on the meteorological parameters, based on the DANSS detector data
The detector DANSS is located under n industrial nuclear reactor at
Kalininskaya Nuclear Power Plant. This location provides ~ 50 m.w.e. reduction
of the cosmic muon flux in the vertical direction, which places the experiment
in an intermediate position between ground and underground experiments in terms
of shielding from the cosmic rays. The detector DANSS is located under an
industrial nuclear reactor at Kalininskaya Nuclear Power Plant. This location
provides ~50 m.w.e. reduction of the cosmic muon flux in the vertical
direction, which places the experiment in an intermediate position between
ground and underground experiments in terms of shielding from the cosmic rays.
The detector's sensitive area consists of 2500 plastic scintillator counters,
each 100x4x1 cm in size, making in total a 1 m volume, which is
surrounded by a muon veto system and multiple layers of passive shielding. The
main goal of the DANSS experiment is to study the antineutrino spectra at
different distances from the source. For this purpose the detector is placed on
a lifting platform, and the data is collected at three positions: 10.9 m, 11.9
m and 12.9 m from the center of the reactor core. The detector is capable of
reconstructing muon tracks passing though the sensitive volume. In this work
the barometric, height and temperature correlation coefficients are calculated
in three areas of the zenith angle using the Duperier approach. These
results are based on the muon data collected during four years.Comment: 7 pages, 3 figures, submitted to JETP letters (in Russian