New constraints on the scattering cross sections of the Kaluza Klein photon as a darkmatter candidate, its annihilation rate in the Sun and the resulting muon flux on Earth are derived.For this purpose, data collected in the IceCube Neutrino Observatory during 532 days of exposurein the austral winters between 2011 and 2014 have been analyzed with Poisson confidence intervals (J. Conrad et al., 2003) and compared to the simulated prediction achieved with the WimpSimsoftware (J. Edsjö et al., 2003). The results do not allow for any detection claim, but they improveby one order of magnitude the constraints formerly presented in R. Abbasi et al. (2010). Despitethe recent results from LHC experiment which discard lower masses for the Kaluza Klein photon (N. Deutschmann et al., 2017), the new constraints are still relevant for masses above 1500 GeV.

<p>A relic density of <i>Weakly Interacting Massive Particles</i> (WIMPs) remaining from the Big Bang constitutes a promising solution to the <i>Dark Matter</i> problem. It is possible for such WIMPs to be trapped by and accumulate in gravitational potentials of massive dense objects such as the Sun. A perfect WIMP candidate appears in certain <i>supersymmetric</i> extensions to the <i>Standard Model</i> of particle physics, where the lightest supersymmetric particle is a <i>neutralino</i> which can be stable, massive and weakly interacting. The neutralinos may annihilate pair-wise and in these interactions neutrinos with energies ranging up to the neutralino mass can be indirectly produced. Hence, a possible population of dark matter neutralinos trapped in the Sun can give rise to an observable neutrino flux.</p><p>The Antarctic Muon And Neutrino Detector Array, AMANDA, is a neutrino telescope that detects Cherenkov light emitted by charged particles created in neutrino interactions in the South Pole glacial ice sheet using an array of light detectors frozen into the deep ice. In this work data taken with the AMANDA-II detector during 2003 are analyzed to measure or put upper bounds on the flux of such neutrinos from the Sun. In the analysis detailed signal and background simulations are compared to measurements. Background rejection filters optimized for various neutralino models have been constructed. No excess above the background expected from neutrinos and muons created in cosmic ray interactions in the atmosphere was found. Instead 90% confidence upper limits have been set on the neutralino annihilation rate in the Sun and the muon flux induced by neutralino signal neutrinos. </p>

<p>The <em>IceCube telescope</em> is built within the ice at the geographical South Pole in the middle of the Antarctica continent. The purpose of the telescope is to detect muon neutrinos, the muon neutrino being an elementary particle with minuscule mass coming from space.</p><p>The detector consists of some 5000 DOMs registering photon hits (light). A muon neutrino traveling through the detector might give rise to a track of photons making up a straight line, and by analyzing the hit output of the DOMs, looking for tracks, neutrinos and their direction can be detected.</p><p>When processing the output, triggers are used. Triggers are calculation- efficient algorithms used to tell if the hits seem to make up a track - if that is the case, all hits are processed more carefully to find the direction and other properties of the track.</p><p>The Track Engine is an additional trigger, specialized to trigger on low- energy events (few track hits), which are particularly difficult to detect. Low-energy events are of special interest in the search for Dark Matter.</p><p>An algorithm for triggering on low-energy events has been suggested. Its main idea is to divide time in overlapping time windows, find all possible pairs of hits in each time window, calculate the spherical coordinates θ and ϕ of the position vectors of the hits of the pairs, histogram the angles, and look for peaks in the resulting 2d-histogram. Such peaks would indicate a straight line of hits, and, hence, a track.</p><p>It is not believed that a software implementation of the algorithm would be fast enough. The Master's Thesis project has had the aim of developing an FPGA implementation of the algorithm.</p><p>Such an FPGA implementation has been developed. Extensive tests on the design has yielded positive results showing that it is fully functional. The design can be synthesized to about 180 MHz, making it possible to handle an incoming hit rate of about 6 MHz, giving a margin of more than twice to the expected average hit rate of 2.6 MHz.</p>

A search for weakly interacting massive particles (WIMPs) annihilating in the Sun was performed with the IceCube and AMANDA neutrino telescopes, using data from 2008 corresponding to 149 days of livetime. Assuming that particles in the dark matter halo scatter and accumulate in the centre of the Sun, Majorana WIMPs may pair-wise annihilate and give rise to a neutrino signal detectable in an experiment at Earth. No excess of muon-neutrinos from the Sun was observed, and limits on the νμ-flux were set for masses between 50 GeV and 5 TeV considering WIMPs annihilating into b‾b and W+W-. Separate limits were also calculated for the case of the lightest Kaluza-Klein particle. The flux limits were converted to limits on the spin-dependent and spin-independent WIMP-proton cross sections, σSD and σSI. The search was combined using a joint likelihood method with AMANDA and IceCube data from 2001-2007, yielding the 90% CL upper limits Φμ &lt; 103 km-2y-1 for a WIMP mass of 1000 GeV and σSD &lt; 1.28×10-4 pb for 250 GeV, both for the W+W- spectrum. / IceCube

A relic density of Weakly Interacting Massive Particles (WIMPs) remaining from the Big Bang constitutes a promising solution to the Dark Matter problem. It is possible for such WIMPs to be trapped by and accumulate in gravitational potentials of massive dense objects such as the Sun. A perfect WIMP candidate appears in certain supersymmetric extensions to the Standard Model of particle physics, where the lightest supersymmetric particle is a neutralino which can be stable, massive and weakly interacting. The neutralinos may annihilate pair-wise and in these interactions neutrinos with energies ranging up to the neutralino mass can be indirectly produced. Hence, a possible population of dark matter neutralinos trapped in the Sun can give rise to an observable neutrino flux. The Antarctic Muon And Neutrino Detector Array, AMANDA, is a neutrino telescope that detects Cherenkov light emitted by charged particles created in neutrino interactions in the South Pole glacial ice sheet using an array of light detectors frozen into the deep ice. In this work data taken with the AMANDA-II detector during 2003 are analyzed to measure or put upper bounds on the flux of such neutrinos from the Sun. In the analysis detailed signal and background simulations are compared to measurements. Background rejection filters optimized for various neutralino models have been constructed. No excess above the background expected from neutrinos and muons created in cosmic ray interactions in the atmosphere was found. Instead 90% confidence upper limits have been set on the neutralino annihilation rate in the Sun and the muon flux induced by neutralino signal neutrinos.

The IceCube telescope is built within the ice at the geographical South Pole in the middle of the Antarctica continent. The purpose of the telescope is to detect muon neutrinos, the muon neutrino being an elementary particle with minuscule mass coming from space. The detector consists of some 5000 DOMs registering photon hits (light). A muon neutrino traveling through the detector might give rise to a track of photons making up a straight line, and by analyzing the hit output of the DOMs, looking for tracks, neutrinos and their direction can be detected. When processing the output, triggers are used. Triggers are calculation- efficient algorithms used to tell if the hits seem to make up a track - if that is the case, all hits are processed more carefully to find the direction and other properties of the track. The Track Engine is an additional trigger, specialized to trigger on low- energy events (few track hits), which are particularly difficult to detect. Low-energy events are of special interest in the search for Dark Matter. An algorithm for triggering on low-energy events has been suggested. Its main idea is to divide time in overlapping time windows, find all possible pairs of hits in each time window, calculate the spherical coordinates θ and ϕ of the position vectors of the hits of the pairs, histogram the angles, and look for peaks in the resulting 2d-histogram. Such peaks would indicate a straight line of hits, and, hence, a track. It is not believed that a software implementation of the algorithm would be fast enough. The Master's Thesis project has had the aim of developing an FPGA implementation of the algorithm. Such an FPGA implementation has been developed. Extensive tests on the design has yielded positive results showing that it is fully functional. The design can be synthesized to about 180 MHz, making it possible to handle an incoming hit rate of about 6 MHz, giving a margin of more than twice to the expected average hit rate of 2.6 MHz.

A search for Weakly Interacting Massive Particles (WIMPs) annihilating in the dark matter halo of the Milky Way was performed, using data from the IceCube Neutrino Observatory and its low-energy extension DeepCore. The data were collected during one year between 2011 to 2012 corresponding to 329.1 days of detector livetime. If WIMPs in the dark matter halo undergo pairwise annihilation they may produce a neutrino signal detectable at the Earth. Assuming annihilation into bb, W+W-, τ+τ-, μ+μ-, νν and a neutrino flavor ratio of 1:1:1 at the detector, cascade events from all neutrino flavors were used to search for an excess of neutrinos matching a dark matter signal spectrum. Two dark matter density profiles for the halo were used; the cored Burkert profile and the cusped NFW profile. No excess of neutrinos from the Galactic halo was observed, and upper limits were set for the thermally averaged product of the WIMP self-annihilation cross section and velocity, &lt;σAv&gt;, in the WIMP mass range 30 GeV to 10 TeV. For the bb annihilation channel and the NFW halo profile, the 90% C.L. upper limits are 9.03×10-22 cm3 s-1 for the mass WIMP 100 GeV and 4.08×10-22 cm3 s-1 for the WIMP mass 3000 GeV. The corresponding upper limits for the μ+μ- annihilation channel are 4.40×10-23 cm3 s-1 and 3.20×10-23 cm3 s-1. / IceCube

The IceCube Neutrino Observatory has reported the observation of 35 neutrino events above 30 TeV with evidence for an astrophysical neutrino flux using data collected from May 2010 to May 2013. These events provide the first high-energy astrophysical neutrino flux ever observed. The sources of these events are currently unknown. IceCube has looked for correlations between these events and a list of TeV photon sources including a catalog of 36 galactic sources and 42 extragalactic sources, correlations with the galactic plane and center, and spatial and temporal clustering. These searches have shown no significant correlations. The isotropic distribution of the event directions gives indications that the events could be extragalactic in nature and therefore may originate in the same processes that generate ultra-high-energy cosmic rays (UHECRs). The sources of these UHECRs are still unknown; however, gamma-ray bursts (GRBs) have been proposed as one possible source class. By determining the source of these high-energy neutrinos, it may be possible to determine the sources of UHECRs as well. This study is a search for directional and temporal correlation between 856 GRBs and the astrophysical neutrino flux observed by IceCube. Nearly 10,000 expanding time windows centered on the earliest reported time of the burst were examined. The time windows start at ±10 s and extend to ±15 days. We find no evidence of correlations for these time windows and set an upper limit on the fraction of the astrophysical flux that can be attributed to the observed GRBs as a function of the time window. GRBs can contribute at most 12% of the astrophysical neutrino flux if the neutrino-GRB correlation time is less than ≈20 hours, and no more than 38% of the astrophysical neutrino flux can be attributed to the known GRBs at time scales up to 15 days. We conclude that GRBs observable by satellites are not solely responsible for IceCube’s astrophysical neutrino flux, even if very long correlation time scales are assumed.

The IceCube neutrino observatory is located in the deep glacial ice below the South Pole. IceCube consists of over 5, 000 photomultiplier tubes regularly spaced throughout a cubic kilometre volume of ice. The photomultiplier tubes are receptive to the light produced by high energy neutrino interactions. As a means of evaluating our understanding of the physics of light propagation, a comparison was made between the data taken from artificial light sources and Monte Carlo simulations of these events. The evaluation was done by comparing the shape of the light arrival-time distributions. The three icemodels compared were the Additionally Heterogeneous Absorption (AHA), South Pole Ice - 1 (Spice) and South Pole Ice - Mie (Spice Mie). The artificial light sources used are LEDs, known as flashers, located within each of the detector modules. The data set used in this study was taken on string 63 with single- photoelectron settings (one LED). Various orientations of the flashing LED and relative position of the light source in the detector, were studied over 15 depths in instrumented ice. Through a χ2 comparison and distribution characteristics it was found that for the majority of cases, simulations which used the Spice Mie ice model matched the data best. There were, however, some isolated cases in which simulations using the Spice 1 or AHA ice models matched the flasher data best.

The IceCube Neutrino Telescope is designed to detect high energy neutrinos with a large array of photomultiplier tubes placed deep within the Antarctic ice. The way that light propagates through the ice needs to be modelled accurately to enable the paths of charged particles to be reconstructed from the distribution of their Cerenkov radiation. Light travelling through even the purest of ice will undergo scattering and absorption processes, however the ice in which IceCube is embedded has optical properties that vary significantly with depth which need to be accurately modelled. Currently, simulation of the muon background using the current ice model is unable to fully replicate experimental data. In this thesis we investigate a potential method of improving on the current generation of ice models. We introduce thin, highly absorbing layers into the current description of the detection medium and investigate the effect on the simulation of muon tracks in IceCube. We find that better agreement between simulation and data can be seen in the occupancy of optical modules, through the introduction of such absorptive layers into the existing ice layers.