Wednesday, April 12, 2017

Connecting IceCube To Sesame Street

The high energy events observed at the IceCube Neutrino Observatory have triggered many investigations interpreting the highly energetic neutrinos detected as decay products of heavy unstable Dark Matter particles. However, while very detailed treatments of the IceCube phenomenology exist, only a few references focus on the (non-trivial) Dark Matter production part -- and all of those rely on relatively complicated new models which are not always testable directly. 
We instead investigate two of the most minimal scenarios possible, where the operator responsible for the IceCube events is directly involved in Dark Matter production. We show that the simplest (four-dimensional) operator is not powerful enough to accommodate all constraints. A more non-minimal setting (at mass dimension six), however, can do both fitting all the data and also allowing for a comparatively small parameter space only, parts of which can be in reach of future observations. 
We conclude that minimalistic approaches can be enough to explain all data required, while complicated new physics seems not to be required by IceCube.
Marco Chianese and Alexander Merle, "A Consistent Theory of Decaying Dark Matter Connecting IceCube to the Sesame Street" (April 11, 2017).

Why Sesame Street (emphasis mine)?
The IceCube Neutrino Observatory, a neutrino telescope located at the Amundsen-Scott South Pole Station, is a unique window to observe highly energetic neutrinos reaching the Earth’s surface, originating from sources as close as the upper regions of the atmosphere up to extra-galactic objects. Its applications to closer sources range from a more precise determination of the atmospheric neutrino flux over measuring the properties of active neutrinos and constraining those of sterile neutrinos to astrophysical findings such as the shadowing effect of the moon on cosmic rays. As for the wider sources, IceCube’s goal is to investigate several types of astrophysical neutrino emitters, its possible applications ranging from astrophysical point sources over Dark Matter annihilation to supernovae. Finally, also certain exotic particles may leave visible signatures in the detector, such as magnetic monopoles.

A big surprise in the data taken between 2010 and 2013 was the detections of three very high energy events. These events have been under such scrutiny and have generated such an amount of interest, that they have even been given names after characters of the Sesame Street for better recognition: Ernie (1.14 PeV), Bert (1.04 PeV), and Big Bird (2.2 PeV).
Sociologically, this makes a bit of sense as a lot of researchers publishing papers in this field are at about the age when they have children watching Sesame Street.

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