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Scholarly Works (2 results)

Article
Peer Reviewed

Measurement of neutron production in atmospheric neutrino interactions at the Sudbury Neutrino Observatory

Recent Work (2019)

Neutron production in GeV-scale neutrino interactions is a poorly studied process. We have measured the neutron multiplicities in atmospheric neutrino interactions in the Sudbury Neutrino Observatory experiment and compared them to the prediction of a Monte Carlo simulation using GENIE and a minimally modified version of GEANT4. We analyzed 837 days of exposure corresponding to Phase I, using pure heavy water, and Phase II, using a mixture of Cl in heavy water. Neutrons produced in atmospheric neutrino interactions were identified with an efficiency of $15.3\%$ and $44.3\%$, for Phase I and II respectively. The neutron production is measured as a function of the visible energy of the neutrino interaction and, for charged current quasi-elastic interaction candidates, also as a function of the neutrino energy. This study is also performed classifying the complete sample into two pairs of event categories: charged current quasi-elastic and non charged current quasi-elastic, and $\nu_{\mu}$ and $\nu_e$. Results show good overall agreement between data and Monte Carlo for both phases, with some small tension with a statistical significance below $2\sigma$ for some intermediate energies.

Cover page: Measurement of neutron production in atmospheric neutrino interactions at the Sudbury Neutrino Observatory

Article

A Search for Neutrinos from the Solar hep Reaction and the Diffuse Supernova Neutrino Background with the Sudbury Neutrino Observatory

Lawrence Berkeley National Laboratory (2006)

A search has been made for neutrinos from the hep reaction in the Sun and from the diffuse supernova neutrino background (DSNB) using data collected during the first operational phase of the Sudbury Neutrino Observatory, with an exposure of 0.65 kilotonne-years. For the hep neutrino search, two events are observed in the effective electron energy range of 14.3 MeV < Teff < 20 MeV where 3.1 background events are expected. After accounting for neutrino oscillations, an upper limit of 2.3 x 104 cm-2s-1 at the 90 percent confidence level is inferred on the integral total flux of hep neutrinos. For DSNB neutrinos, no events are observed in the effective electron energy range of 21 MeV < Teff < 35 MeV and, consequently, an upper limit on the nu e component of the DSNB fluxin the neutrino energy range of 22.9 MeV < E nu < 36.9 MeV of 70 cm-2-1 is inferred at the 90 percent confidence level. This is an improvement by a factor of 6.5 on the previous best upper limit on the hep neutrino flux and by two orders of magnitude on the previous upper limit on the nu e component of the DSNB flux.