A cubic kilometre of South Pole ice looking for dark matter

Australian Institute of Physics Congress

UK researcher Anthony Brown reported on the IceCube neutrino telescope under construction at the South Pole.

The first stages are up and running, looking for high energy neutrinos from a variety of astrophysical sources, including dark matter.

Further information:

Latest results from the IceCube Experiment.

Anthony M Brown, for the IceCube Collaboration
Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch, NZ

Abstract summary:

The IceCube Collaboration is currently building a neutrino detector at the South Pole to observe high energy neutrinos from a variety of astrophysical sources. In this paper we review the current status of the IceCube experiment, highlighting some of the results obtained so far.

Abstract:

I. INTRODUCTION
Neutrinos afford us a unique view of the Universe. Due to their small interaction cross-section and neutral charge, neutrinos are able to escape, undeflected, from some of the most dense regions of the Universe. As such, neutrinos offer us a unique probe of the most extreme processes occurring in cosmic sources.

The production of high energy neutrinos can occur via the decay of charged mesons, with the charged mesons being produced through the interaction of accelerated hadrons with ambient matter or radiation fields. In an astrophysical scenario, the production of high energy neutrinos is believed to occur in numerous sources where hadronic, or Cosmic Ray, acceleration is taking place. These sources include Active Galactic Nuclei (AGN), supernova remnants or microquasars. Therefore, neutrino astronomy places an important role, in the context of a multi-messenger approach, in conclusively proving the origin of Cosmic Ray particles.

Searching for neutrino signatures from Dark Matter (DM) annihilation is another key goal of the IceCube neutrino telescope. Through elastic scattering, weakly interacting massive particles (WIMPs), relics from the Big Bang, are believed to accumulate at the centre of massive celestial objects such as the Sun. This over density of WIMPs results in an increased selfannihilation rate of these primordial particles, producing a measurable high energy neutrino flux in the process. Observing the presence, or indeed absence, of a neutrino flux allows us to constrain the contribution of WIMPs to the universal DM population.

With a view to pursuing these scientific goals, among others, the IceCube collaboration is currently building the world’s largest neutrino telescope in the clear ice of Antarctica, at the geographic South Pole. Due to be completed in early 2011, the final detector will be contain 86 strings throughout 1 cubic kilometre of ice. Each string will house 60 optical sensors deployed at depths between 1450 and 2450 meters below the surface of Antarctica’s ice (see Figure 1).

The physical dimensions of IceCube have been optimized to detect all flavours of neutrinos (Ve, Vµ and Vt), over a wide range of energies, from 100 GeV to beyond 109 GeV, with unprecedented energy and angular resolution. Coupling these important detector characteristics with the sheer size of the detector allows IceCube to place some of the most restrictive limits to date on a wide variety of astro-particle models.

After reviewing the detection technique and performance of the IceCube neutrino telescope, we will discuss some of the recent results of the IceCube experiment including the results of our point source search, the strongest limits on WIMP annihilation set to date and the first detection of Cosmic Ray anisotropy in the Southern sky.

Contact:

Anthony Brown, anthony.brown@canterbury.ac.nz
Web resource:
http://icecube.wisc.edu