Demystifying the PeV cascades in IceCube: Less (energy) is more (events)

Ranjan Laha, John F. Beacom, Basudeb Dasgupta, Shunsaku Horiuchi, Kohta Murase

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87 Scopus citations


The IceCube neutrino observatory has detected two cascade events with energies near 1 PeV [A. Ishihara Proceedings of Neutrino 2012 Conference,; M. Aartsen et al. (IceCube Collaboration) Phys. Rev. Lett. 111, 021103 (2013)]. Without invoking new physics, we analyze the source of these neutrinos. We show that atmospheric conventional neutrinos and cosmogenic neutrinos (those produced in the propagation of ultra-high-energy cosmic rays) are strongly disfavored. For atmospheric prompt neutrinos or a diffuse background of neutrinos produced in astrophysical objects, the situation is less clear. We show that there is tension with observed data, but that the details depend on the least-known aspects of the IceCube analysis. Very likely, prompt neutrinos are disfavored and astrophysical neutrinos are plausible. We demonstrate that the fastest way to reveal the origin of the observed PeV neutrinos is to search for neutrino cascades in the range below 1 PeV, for which dedicated analyses with high sensitivity have yet to appear, and where many more events could be found.

Original languageEnglish (US)
Article number043009
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number4
StatePublished - Aug 21 2013

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)


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