Observation of a point source of astrophysical neutrinos would be a "smoking
gun" signature of a cosmic-ray accelerator. While IceCube has recently
discovered a diffuse flux of astrophysical neutrinos, no localized point source
has been observed. Previous IceCube searches for point sources in the southern
sky were restricted by either an energy threshold above a few hundred TeV or
poor neutrino angular resolution. Here we present a search for southern sky
point sources with greatly improved sensitivities to neutrinos with energies
below 100 TeV. By selecting charged-current $
u_{mu}$ interacting inside the
detector, we reduce the atmospheric background while retaining efficiency for
astrophysical neutrino-induced events reconstructed with sub-degree angular
resolution. The new event sample covers three years of detector data and leads
to a factor of ten improvement in sensitivity to point sources emitting below
100 TeV in the southern sky. No statistically significant evidence of point
sources was found, and upper limits are set on neutrino emission from
individual sources. A posteriori analysis of the highest-energy ~100 TeV
starting event in the sample found that this event alone represents a
$2.8sigma$ deviation from the hypothesis that the data consists only of
atmospheric background.
Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.
browser Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)
REGISTER
Did you like this article? 
