Abstract
We report on a search for electron antineutrinos (
ν
¯
e
) from astrophysical sources in the neutrino energy range 8.3–30.8 MeV with the KamLAND detector. In an exposure of 6.72 kton-year of ...the liquid scintillator, we observe 18 candidate events via the inverse beta decay reaction. Although there is a large background uncertainty from neutral current atmospheric neutrino interactions, we find no significant excess over background model predictions. Assuming several supernova relic neutrino spectra, we give upper flux limits of 60–110 cm
−2
s
−1
(90% confidence level, CL) in the analysis range and present a model-independent flux. We also set limits on the annihilation rates for light dark matter pairs to neutrino pairs. These data improve on the upper probability limit of
8
B solar neutrinos converting into
ν
¯
e
,
P
ν
e
→
ν
¯
e
<
3.5
×
10
−
5
(90% CL) assuming an undistorted
ν
¯
e
shape. This corresponds to a solar
ν
¯
e
flux of 60 cm
−2
s
−1
(90% CL) in the analysis energy range.
The detection of electron antineutrinos produced by natural radioactivity in the Earth could yield important geophysical information. The Kamioka liquid scintillator antineutrino detector (KamLAND) ...has the sensitivity to detect electron antineutrinos produced by the decay of 238U and 232Th within the Earth. Earth composition models suggest that the radiogenic power from these isotope decays is 16 TW, approximately half of the total measured heat dissipation rate from the Earth. Here we present results from a search for geoneutrinos with KamLAND. Assuming a Th/U mass concentration ratio of 3.9, the 90 per cent confidence interval for the total number of geoneutrinos detected is 4.5 to 54.2. This result is consistent with the central value of 19 predicted by geophysical models. Although our present data have limited statistical power, they nevertheless provide by direct means an upper limit (60 TW) for the radiogenic power of U and Th in the Earth, a quantity that is currently poorly constrained.
Abstract
We present the results of a search for MeV-scale electron antineutrino events in KamLAND coincident with the 60 gravitational wave events/candidates reported by the LIGO/Virgo collaboration ...during their second and third observing runs. We find no significant coincident signals within a ±500 s timing window from each gravitational wave and present 90% C.L. upper limits on the electron antineutrino fluence between 10
8
and 10
13
cm
−2
for neutrino energies in the energy range of 1.8–111 MeV.
Initial performance of the CUORE-0 experiment Artusa, D. R.; Avignone, F. T.; Azzolini, O. ...
The European physical journal. C, Particles and fields,
08/2014, Letnik:
74, Številka:
8
Journal Article
Recenzirano
Odprti dostop
CUORE-0 is a cryogenic detector that uses an array of tellurium dioxide bolometers to search for neutrinoless double-beta decay of
130
Te
. We present the first data analysis with
7.1
kg
·
y
of total
...TeO
2
exposure focusing on background measurements and energy resolution. The background rates in the neutrinoless double-beta decay region of interest (2.47 to
2.57
MeV
) and in the
α
background-dominated region (2.70 to
3.90
MeV
) have been measured to be
0.071
±
0.011
and
0.019
±
0.002
counts
/
(
keV
·
kg
·
y
)
, respectively. The latter result represents a factor of 6 improvement from a predecessor experiment, Cuoricino. The results verify our understanding of the background sources in CUORE-0, which is the basis of extrapolations to the full CUORE detector. The obtained energy resolution (full width at half maximum) in the region of interest is
5.7
keV
. Based on the measured background rate and energy resolution in the region of interest, CUORE-0 half-life sensitivity is expected to surpass the observed lower bound of Cuoricino with one year of live time.
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