In this project we intend to work towards the first observation of astrophysical tau-neutrinos.

We will use data taken by the IceCube neutrino observatory located deep in the ice at the

South Pole. IceCube has an instrumented volume of a cubic kilometre and is by far the largest

neutrino detector in the world. It is sensitive to neutrinos with energies between 1010 and

1018 eV.

Of the three neutrino flavours, the tau-neutrino is experimentally the least well known. It was

only discovered in 2000, and just a few of them have been observed. From a particle astro-

physics point of view they are particularly attractive study objects because they are almost not

present among the atmospheric neutrinos, created when high energy cosmic rays hit the Earth’s

atmosphere. Their presence in the detector thus immediately points towards an astrophysical

origin.

The IceCube neutrino observatory recently published an upper limit on the flux of extrasolar

tau-neutrinos which is not yet low enough to seriously challenge models for their production.

However, this was done on the basis of a relatively short observation period with an unfinished

detector. The purpose of this project is to search for high energy tau-neutrinos in the full

IceCube detector, completed in December 2010, using a dataset spanning several years of

observation, and looking for the different possible signatures of tau-neutrinos in the detector.