[Paper Review] Search for the Kaluza-Klein Dark Matter with the AMANDA/IceCube Detectors

M. Danninger, K. Han|arXiv (Cornell University)|Jun 22, 2009

Dark Matter and Cosmic Phenomena3 references3 citations

TL;DR

This paper presents a search for Kaluza-Klein dark matter (LKP) via high-energy neutrinos produced by WIMP annihilation in the Sun, using AMANDA-II and IceCube-22 data. It projects competitive sensitivity to the spin-dependent LKP-proton scattering cross section, achieving limits comparable to direct detection experiments and probing a theoretically motivated mass range from 500 to 1500 GeV.

ABSTRACT

A viable WIMP candidate, the lightest Kaluza-Klein particle (LKP), is motivated by theories of universal extra dimensions. LKPs can scatter off nuclei in large celestial bodies, like the Sun, and become trapped within their deep gravitational wells, leading to high WIMP densities in the object's core. Pair-wise LKP annihilation could lead to a detectable high energy neutrino flux from the center of the Sun in the IceCube neutrino telescope. We describe an ongoing search for Kaluza-Klein solar WIMPs with the AMANDA-II data for the year 2001, and also present a UED dark matter sensitivity projected to 180 days from a study of data taken with the combined AMANDA II and IceCube detector in the year 2007. A competitive sensitivity, compared to existing direct and indirect search experiments, on the spin-dependent cross section of the LKP on protons is also presented.

Motivation & Objective

• To search for Kaluza-Klein dark matter (LKP) through high-energy neutrino signals from WIMP annihilation in the Sun.
• To assess the sensitivity of the AMANDA-II and IceCube-22 detector configurations to LKP-induced muon fluxes.
• To project constraints on the spin-dependent scattering cross section of LKPs on protons, comparing with direct detection limits.
• To evaluate the performance of combined AMANDA and IceCube data for indirect dark matter detection in the context of Universal Extra Dimensions (UED).

Proposed method

• Utilizes data from the AMANDA-II detector (2001) and combined AMANDA-II + IceCube-22 (2007) to search for upward-going muons from neutrino interactions in the detector.
• Applies a solar WIMP analysis that selects data when the Sun is below the horizon (zenith angle 90°–113°), using the Earth as a background filter.
• Employs Monte Carlo simulations using CORSIKA for atmospheric muons, ANIS for atmospheric neutrinos, and WIMPSIM for LKP signal generation with masses from 250 GeV to 3000 GeV.
• Calculates the effective volume $V_{ ext{eff}}$ for each annihilation channel using the combined signal probability density function, weighted by branching ratios.
• Derives the 90% confidence level upper limit on the neutrino-to-muon conversion rate $\overline{\Gamma}_{\nu\rightarrow\mu}^{90\%}$, then converts it to the annihilation rate $\overline{\Gamma}_{A}^{90\%}$ using channel-dependent constants.
• Uses the equilibrium condition $\Gamma_{A} = C^{\odot}$ to derive the spin-dependent cross section via $\sigma_{\text{H,SD}} \simeq 0.597 \times 10^{-24} \text{pb} \cdot (m_{B^{(1)}}/1\text{TeV})^2 \cdot (\overline{\Gamma}_{A}^{90\%}/s^{-1})$.

Experimental results

Research questions

• RQ1 What is the sensitivity of the AMANDA-II and IceCube-22 detector configuration to high-energy neutrinos from LKP annihilation in the Sun?
• RQ2 How does the projected sensitivity on the spin-dependent LKP-proton scattering cross section compare to existing direct detection limits?
• RQ3 Can the combined AMANDA and IceCube data probe the theoretically predicted region of LKP masses in Universal Extra Dimensions models?
• RQ4 What is the expected performance of the full IceCube-80 detector in improving constraints on LKP WIMP theories?

Key findings

• The projected sensitivity for 180 days of livetime with IceCube-22 + AMANDA achieves a 90% confidence level upper limit on the muon flux from LKP annihilation in the Sun, with effective volume reaching up to ~1.2 km³ for LKP masses around 1 TeV.
• The analysis projects sensitivity to the spin-dependent LKP-proton scattering cross section in the range of $10^{-24}$ pb for LKP masses between 500 GeV and 1500 GeV, matching the sensitivity of direct detection experiments.
• Theoretical predictions for the spin-dependent cross section (shaded region in Fig. 3) span from $10^{-25}$ to $10^{-24}$ pb depending on the KK-quark mass, and the projected sensitivity covers the lower end of this range.
• The capture rate of LKPs in the Sun is dominated by the spin-dependent component, justifying the focus on this channel for sensitivity optimization.
• The analysis excludes LKP masses below 300 GeV due to collider constraints and masses above 1500 GeV due to WMAP relic density constraints, narrowing the viable parameter space.
• The full IceCube-80 detector is expected to significantly improve sensitivity, enabling strong constraints on LKP WIMP models due to the hard energy signature of $\nu_\mu$ from LKP annihilation.