arXiv:1001.1381v2 [astro-ph.HE] 16 Feb 2010 Closing the Window on Strongly Interacting Dark Matter with IceCube Ivone F. M. Albuquerque 1, 2 and Carlos P´ erez de los Heros 3 $^{1}$Center for Particle Astrophysics, Fermi National Accelerator Laboratory, Batavia, IL, 60510. USA $^{2}$Instituto de F´ısica, Universidade de S˜ ao Paulo, S˜ ao Paulo, Brazil $^{3}$Department of Physics and Astronomy. Uppsala University. Uppsala. Sweden (Dated: October 25, 2018) We use the recent results on dark matter searches of the 22-string IceCube detector to probe the remaining allowed window for strongly interacting dark matter in the mass range 10 $^{4}$< m X < 10 15 GeV. We calculate the expected signal in the 22-string IceCube detector from the annihilation of such particles captured in the Sun and compare it to the detected background. As a result, the remaining allowed region in the mass versus cross section parameter space is ruled out. We also show the expected sensitivity of the complete IceCube detector with 86 strings. PACS numbers: 95.35.+d, 95.85.Ry Keywords: Super-heavy dark matter, Simpzillas, IceCube square hatched) was ruled out by many different exper- iments underground or space-borne [7, 8] $^{1}$. More re- cently, a search for simpzillas using results from direct detection experiments excluded most of the remaining parameter space for high masses (solid yellow, labeled “Direct”) [9]. A recent analysis further constrained the allowed region by using the Earth heat flow to set con- strains on the annihilation of captured dark matter in the Earth’s center (green striped, labelled “Earth heat”) [10]. The blank triangular regions in Figure 1 remained un- probed until this work. The search for dark matter is currently one of the most active fields of research in experimental astroparti- cle physics. Common candidates are weakly interacting massive particles (WIMPs), with only weak and gravi- tational interactions with normal matter, and which en- compass a variety of particle types in the mass range from a few tens of GeV to a few hundred TeV, where the upper limit is based on theoretical arguments to preserve unitarity [1]. Among WIMP candidates are the lightest neutralino arising in the Minimal Supersymmetric Ex- tension of the Standard Model (MSSM), or the lightest Kaluza-Klein mode in models of Universal Extra Dimen- sions (UED) [2]. These candidates are thermal relics from the Big Bang, and since they are stable, assumed to be able to contribute to the dark matter content in the halos of galaxies. In a different scenario, it has been shown that super- massive particles can be produced in the early Universe and account for dark matter, independently of their in- teraction strength with normal matter. In order to avoid the mass limit imposed by unitarity constraints, one can model non–thermal production of super-massive parti- cles [3, 4]. The large mass will prevent the particle to ever get into thermal equilibrium with the primordial plasma. Super-massive dark matter candidates were coined wim- pzillas [5] if assumed to interact weakly with matter and simpzillas [6] if the interaction is strong. The produc- tion mechanism discussed in [3, 4] favours particles with $^{masses of the order of the inflaton mass (}$∼10 12 GeV), but particles of masses as low as a few hundred GeV can also be produced, normally denoted as strongly interact- ing massive particles (SIMPs). Although SIMPs are in general taken to be in the mass range ∼ 10 4 ≲ m$_{X}$ ≲ 10 8 GeV, and simpzillas, with masses m$_{X}$ > 10 8 GeV, we will generically call them either simpzillas. Searches for simpzillas have been carried out in a va- riety of ways in the past. Figure 1 shows the current ex- clusion region in the mass versus simpzilla–nucleon cross section parameter space. The “Mine/Space” region (blue In this paper we explore the capabilities of IceCube to detect high-energy neutrinos from simpzilla annihila- tions in the Sun. The baseline IceCube geometry con- sists of 80 strings with 60 digital optical modules each, instrumenting 1 km 3 of ice at depths between 1450 m– 2450 m near the geographic South Pole [15]. Recently, an addition of six strings forming a denser core in the middle of the IceCube array has been proposed in order to lower the neutrino energy threshold of the detector to about 10 GeV, the so–called “DeepCore” array [16]. Whether thermally produced or not, stable dark mat- ter candidates can gravitationally accumulate as a halo in our galaxy, becoming bound in orbits in the solar sys- tem. Further energy losses can occur in elastic interac- tions with matter in large celestial bodies, like the Sun. If they lose enough energy they can fall below the escape velocity of the object, accumulating in its center and an- nihilating therein [11–13]. Neutrinos of energies O (100 GeV) can be produced from the decays of the annihi- lation products. This allows for an ’indirect search’ for dark matter with neutrino telescopes, based on a search for an excess neutrino flux from the direction of the Sun over the known atmospheric neutrino background. Pre- dictions of simpzilla event rates and neutrino telescopes sensitivity have been anticipated in [14]. I. INTRODUCTION 1 Note that part of the exclusion region shown in [8] and repro- duced in [10] was corrected in [7]