22 research outputs found
KamLAND's search for correlated low-energy electron antineutrinos with astrophysical neutrinos from IceCube
We report the results of a search for MeV-scale astrophysical neutrinos in
KamLAND presented as an excess in the number of coincident neutrino
interactions associated with the publicly available high-energy neutrino
datasets from the IceCube Neutrino Observatory. We find no statistically
significant excess in the number of observed low-energy electron antineutrinos
in KamLAND, given a coincidence time window of 500s, 1,000s,
3,600s, and 10,000s around each of the IceCube neutrinos. We use this
observation to present limits from 1.8 MeV to 100 MeV on the electron
antineutrino fluence, assuming a mono-energetic flux. We then compare the
results to several astrophysical measurements performed by IceCube and place a
limit at the 90% confidence level on the electron antineutrino isotropic
thermal luminosity from the TXS 0506+056 blazar.Comment: 12 pages, 5 figure
Search for solar flare neutrinos with the KamLAND detector
We report the result of a search for neutrinos in coincidence with solar flares from the GOES flare database. The search was performed on a 10.8 kton-year exposure of KamLAND collected from 2002 to 2019. This large exposure allows us to explore previously unconstrained parameter space for solar flare neutrinos. We found no statistical excess of neutrinos and established 90% confidence level upper limits of 8.4 × 10^7 cm^−2 (3.0 × 10^9 cm^−2) on the electron antineutrino (electron neutrino) fluence at 20 MeV normalized to the X12 flare, assuming that the neutrino fluence is proportional to the X-ray intensity.https://arxiv.org/abs/2105.0245
Limits on astrophysical antineutrinos with the KamLAND Experiment
We report on a search for electron antineutrinos (n¯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 8B solar neutrinos converting into , (90% CL) assuming an undistorted shape. This corresponds to a solar flux of 60 cm−2 s−1 (90% CL) in the analysis energy range.https://arxiv.org/abs/2108.0852
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A Search for Correlated Low-energy Electron Antineutrinos in KamLAND with Gamma-Ray Bursts
We present the results of a time-coincident event search for low-energy electron antineutrinos in the KamLAND detector with gamma-ray bursts (GRBs) from the Gamma-ray Coordinates Network and Fermi Gamma-ray Burst Monitor. Using a variable coincidence time window of ±500 s plus the duration of each GRB, no statistically significant excess above the background is observed. We place the world's most stringent 90% confidence level upper limit on the electron antineutrino fluence below 17.5 MeV. Assuming a Fermi-Dirac neutrino energy spectrum from the GRB source, we use the available redshift data to constrain the electron antineutrino luminosity and effective temperature
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Search for Supernova Neutrinos and Constraint on the Galactic Star Formation Rate with the KamLAND Data
Abstract
We present the results of a search for core-collapse supernova neutrinos, using long-term KamLAND data from 2002 March 9 to 2020 April 25. We focus on the electron antineutrinos emitted from supernovae in the energy range of 1.8–111 MeV. Supernovae will make a neutrino event cluster with the duration of ∼10 s in the KamLAND data. We find no neutrino clusters and give the upper limit on the supernova rate to be 0.15 yr−1 with a 90% confidence level. The detectable range, which corresponds to a >95% detection probability, is 40–59 kpc and 65–81 kpc for core-collapse supernovae and failed core-collapse supernovae, respectively. This paper proposes to convert the supernova rate obtained by the neutrino observation to the Galactic star formation rate. Assuming a modified Salpeter-type initial mass function, the upper limit on the Galactic star formation rate is <(17.5–22.7) M
⊙ yr−1 with a 90% confidence level
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KamLAND's search for correlated low-energy electron antineutrinos with astrophysical neutrinos from IceCube
We report the results of a search for MeV-scale astrophysical neutrinos in
KamLAND presented as an excess in the number of coincident neutrino
interactions associated with the publicly available high-energy neutrino
datasets from the IceCube Neutrino Observatory. We find no statistically
significant excess in the number of observed low-energy electron antineutrinos
in KamLAND, given a coincidence time window of 500s, 1,000s,
3,600s, and 10,000s around each of the IceCube neutrinos. We use this
observation to present limits from 1.8 MeV to 100 MeV on the electron
antineutrino fluence, assuming a mono-energetic flux. We then compare the
results to several astrophysical measurements performed by IceCube and place a
limit at the 90% confidence level on the electron antineutrino isotropic
thermal luminosity from the TXS 0506+056 blazar
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KamLAND's search for correlated low-energy electron antineutrinos with astrophysical neutrinos from IceCube
We report the results of a search for MeV-scale astrophysical neutrinos in KamLAND presented as an excess in the number of coincident neutrino interactions associated with the publicly available high-energy neutrino datasets from the IceCube Neutrino Observatory. We find no statistically significant excess in the number of observed low-energy electron antineutrinos in KamLAND, given a coincidence time window of ±500 s, ±1,000 s, ±3,600 s, and ±10,000 s around each of the IceCube neutrinos. We use this observation to present limits from 1.8 MeV to 100 MeV on the electron antineutrino fluence, assuming a mono-energetic flux. We then compare the results to several astrophysical measurements performed by IceCube and place a limit at the 90% confidence level on the electron antineutrino isotropic thermal luminosity from the TXS 0506+056 blazar
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Search for the Majorana Nature of Neutrinos in the Inverted Mass Ordering Region with KamLAND-Zen
The KamLAND-Zen experiment has provided stringent constraints on the neutrinoless double-beta (0νββ) decay half-life in ^{136}Xe using a xenon-loaded liquid scintillator. We report an improved search using an upgraded detector with almost double the amount of xenon and an ultralow radioactivity container, corresponding to an exposure of 970 kg yr of ^{136}Xe. These new data provide valuable insight into backgrounds, especially from cosmic muon spallation of xenon, and have required the use of novel background rejection techniques. We obtain a lower limit for the 0νββ decay half-life of T_{1/2}^{0ν}>2.3×10^{26}  yr at 90% C.L., corresponding to upper limits on the effective Majorana neutrino mass of 36-156 meV using commonly adopted nuclear matrix element calculations
A Search for Correlated Low-energy Electron Antineutrinos in KamLAND with Gamma-Ray Bursts
We present the results of a time-coincident event search for low-energy electron antineutrinos in the KamLAND detector with gamma-ray bursts (GRBs) from the Gamma-ray Coordinates Network and Fermi Gamma-ray Burst Monitor. Using a variable coincidence time window of ±500 s plus the duration of each GRB, no statistically significant excess above the background is observed. We place the world’s most stringent 90% confidence level upper limit on the electron antineutrino fluence below 17.5 MeV. Assuming a Fermi–Dirac neutrino energy spectrum from the GRB source, we use the available redshift data to constrain the electron antineutrino luminosity and effective temperature
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Search for Solar Flare Neutrinos with the KamLAND detector
We report the result of a search for neutrinos in coincidence with solar
flares from the GOES flare database. The search was performed on a 10.8
kton-year exposure of KamLAND collected from 2002 to 2019. This large exposure
allows us to explore previously unconstrained parameter space for solar flare
neutrinos. We found no statistical excess of neutrinos and established 90%
confidence level upper limits of cm ( cm) on electron anti-neutrino (electron neutrino) fluence at 20
MeV normalized to the X12 flare, assuming that the neutrino fluence is
proportional to the X-ray intensity