Search for hep solar neutrinos and the diffuse supernova neutrino background using all three phases of the Sudbury Neutrino Observatory

A search has been performed for neutrinos from two sources, the hep reaction in the solar pp fusion chain and the upsilon e component of the diffuse supernova neutrino background (DSNB), using the full dataset of the Sudbury Neutrino Observatory with a total exposure of 2.47 kton-years after fiducialization. The hep search is performed using both a single-bin counting analysis and a likelihood fit. We find a best-fit flux that is compatible with solar model predictions while remaining consistent with zero flux, and set a onesided upper limit of Phi(hep) < 30 x 10(3) cm(-2) s(-1) [90% credible interval (CI)]. No events are observed in the DSNB search region, and we set an improved upper bound on the nu(e) component of the DSNB flux of Phi(DSNB)(nu e) < 19 cm(-2) s(-1) (90% CI) in the energy range 22.9 < E-nu < 36.9 MeV.