We have conducted a new search for the diffuse supernova neutrino background (DSNB) flux at SuperKamiokande (SK), with a 22.5 x 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 (nu) over bar (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 x 5823 kton . days of data. This analysis has the world's best sensitivity to the DSNB (nu) over bar (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 (nu) over bar (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.

Diffuse supernova neutrino background search at Super-Kamiokande

Berardi, V
Membro del Collaboration Group
;
2021

Abstract

We have conducted a new search for the diffuse supernova neutrino background (DSNB) flux at SuperKamiokande (SK), with a 22.5 x 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 (nu) over bar (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 x 5823 kton . days of data. This analysis has the world's best sensitivity to the DSNB (nu) over bar (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 (nu) over bar (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.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11589/244100
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • Scopus 9
  • ???jsp.display-item.citation.isi??? 7
social impact