Diffuse supernova neutrino background search at Super-Kamiokande
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
We have conducted a new search for the diffuse supernova neutrino background (DSNB) flux at SuperKamiokande (SK), with a 22.5 × 2970-kton · day exposure from its fourth operational phase IV. With the
new analysis we improve on the existing background reduction techniques and systematic uncertainties and
take advantage of an improved neutron tagging algorithm to lower the energy threshold compared to the
previous phases of SK. This allows for setting the world’s most stringent upper limit on the extraterrestrial
ν¯e flux, for neutrino energies below 31.3 MeV. The SK-IV results are combined with the ones from the first three phases of SK to perform a joint analysis using 22.5 × 5823 kton · days of data. This analysis has the
world’s best sensitivity to the DSNB ν¯e flux, comparable to the predictions from various models. For
neutrino energies larger than 17.3 MeV, the new combined 90% CL upper limits on the DSNB ν¯e flux lie
around 2.7 cm−2 · sec−1, strongly disfavoring the most optimistic predictions. Finally, potentialities of the
gadolinium phase of SK and the future Hyper-Kamiokande experiment are discussed.
new analysis we improve on the existing background reduction techniques and systematic uncertainties and
take advantage of an improved neutron tagging algorithm to lower the energy threshold compared to the
previous phases of SK. This allows for setting the world’s most stringent upper limit on the extraterrestrial
ν¯e flux, for neutrino energies below 31.3 MeV. The SK-IV results are combined with the ones from the first three phases of SK to perform a joint analysis using 22.5 × 5823 kton · days of data. This analysis has the
world’s best sensitivity to the DSNB ν¯e flux, comparable to the predictions from various models. For
neutrino energies larger than 17.3 MeV, the new combined 90% CL upper limits on the DSNB ν¯e flux lie
around 2.7 cm−2 · sec−1, strongly disfavoring the most optimistic predictions. Finally, potentialities of the
gadolinium phase of SK and the future Hyper-Kamiokande experiment are discussed.
Date Issued
2021-12-10
Date Acceptance
2021-11-02
Citation
Physical Review D: Particles, Fields, Gravitation and Cosmology, 2021, 104 (12), pp.1-41
ISSN
1550-7998
Publisher
American Physical Society
Start Page
1
End Page
41
Journal / Book Title
Physical Review D: Particles, Fields, Gravitation and Cosmology
Volume
104
Issue
12
Copyright Statement
© 2021 American Physical Society
Identifier
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Subjects
Astronomy & Astrophysics
CALIBRATION
CORE-COLLAPSE
FINITE NUCLEI
Physical Sciences
Physics
Physics, Particles & Fields
Science & Technology
SPECTRA
STARS
Publication Status
Published
Article Number
122002
Date Publish Online
2021-12-10