[Paper Review] Dark matter searches with IceCube

C. Pérez de los Heros|arXiv (Cornell University)|Dec 1, 2010

Dark Matter and Cosmic Phenomena3 references4 citations

TL;DR

This paper presents results from dark matter searches using the IceCube neutrino telescope, focusing on WIMPs, Kaluza-Klein particles, and Simpzillas via neutrino signals from the Sun, Galactic Center, and halo. Using 22- and 40-string configurations, IceCube sets stringent limits on spin-dependent cross-sections and self-annihilation cross-sections, with the Galactic Center analysis reaching sensitivity comparable to Fermi and Pamela satellite data, particularly disfavoring annihilation cross-sections above 10⁻²² cm³/s.

ABSTRACT

The construction of the IceCube neutrino observatory is practically terminated. At the time of this writing, and with 79 strings taking data out of the 86 foreseen, we are one deployment season away from completion. The detector, however, has been taking data since 2006 in different partial configurations. We have evaluated these data for evidence of dark matter annihilations in the Sun, in the Galactic Center and in the Galactic Halo, searching for an excess neutrino flux over the expected atmospheric neutrino background. This contribution reviews the results of dark matter searches for WIMPs, Kaluza-Klein modes and superheavy candidates (Simpzillas), using the 22- and 40-string configurations of IceCube. The results are presented in the form of muon flux limits, constrains on the candidates' spin-dependent cross-section with protons, and constrains in the self-annihilation cross section. These results are presented in the context of direct searches and searches in space

Motivation & Objective

• To search for high-energy neutrino signals from dark matter annihilations in the Sun, Galactic Center, and Galactic halo using IceCube data.
• To constrain the properties of dark matter candidates such as neutralinos, Kaluza-Klein particles, and Simpzillas through observed neutrino fluxes.
• To improve sensitivity to low-mass dark matter candidates by lowering the energy threshold using the DeepCore extension.
• To enable multi-wavelength dark matter searches by comparing neutrino results with photon and cosmic-ray data from Fermi and Pamela.
• To validate IceCube’s capability as a directional, background-resistant probe of dark matter via neutrino telescopes.

Proposed method

• IceCube detects Cherenkov light from relativistic particles produced in neutrino interactions using 86 strings of digital optical modules (DOMs) deployed in Antarctic ice.
• The 22-string and 40-string configurations collected data from 2007–2009, with the 40-string setup enabling first Galactic Center searches.
• A veto region using upper-layer DOMs and surrounding strings allows identification of starting tracks and suppression of atmospheric muon backgrounds.
• The analysis uses the on-source minus off-source event count method (ΔN = N_on − N_off) to test for excesses above atmospheric neutrino background.
• Limits on the self-annihilation cross-section ⟨σAv⟩ are derived from non-observation of signal excesses in halo and Galactic Center regions.
• Systematic uncertainties are included in halo analysis; Galactic Center results are preliminary and lack full systematic evaluation.

Experimental results

Research questions

• RQ1 Can IceCube detect a neutrino flux from dark matter annihilations in the Sun, Galactic Center, or Galactic halo?
• RQ2 What are the constraints on the spin-dependent cross-section of WIMPs with protons from IceCube data?
• RQ3 How do IceCube’s limits on the self-annihilation cross-section ⟨σAv⟩ compare with those from Fermi and Pamela satellite observations?
• RQ4 To what extent does the DeepCore extension lower the energy threshold and improve sensitivity to low-mass dark matter candidates?
• RQ5 Can neutrino telescopes provide a cleaner signal than photon or cosmic-ray detectors for dark matter annihilation?

Key findings

• IceCube sets 90% confidence level limits on the muon flux from neutralino annihilations in the Sun, improving upon previous experiments like SuperK, Baksan, and MACRO.
• The 40-string configuration enabled the first direct search for dark matter annihilations in the Galactic Center, yielding competitive limits on the self-annihilation cross-section ⟨σAv⟩.
• For the τ⁺τ⁻ annihilation channel, IceCube’s Galactic Center analysis disfavors values of ⟨σAv⟩ above approximately 10⁻²² cm³/s, matching the 90% CL contour of Fermi and Pamela best-fit data.
• The Galactic Halo analysis shows that different dark matter density models (e.g., NFW) yield nearly identical limits at the Solar System location (8.5 kpc), reducing model dependence.
• Systematic uncertainties are included in halo analysis but not yet fully evaluated in the Galactic Center analysis, indicating a need for further refinement.
• DeepCore’s deployment lowers the energy threshold to tens of GeV, significantly extending IceCube’s sensitivity to dark matter candidates below 100 GeV.