Atmospheric neutrinos are produced in air showers, when cosmic ray primaries hit the Earths atmosphere and interact hadronically. The conventional neutrino flux, which dominates the neutrino data measured in the GeV to TeV range by neutrino telescope
s, is produced by the decay of charged pions and kaons. Prompt atmospheric neutrinos are produced by the decay of heavier mesons typically containing a charm quark. Their production is strongly suppressed, but they are expected to exhibit a harder energy spectrum. Hence, they could dominate the atmospheric neutrino flux at energies above ~ 100 TeV. Such a prompt atmospheric flux component has not yet been observed. Therefore, it is an interesting signal in a diffuse neutrino search, but also a background in the search for a diffuse astrophysical neutrino flux. The sensitivity of diffuse neutrino searches with the IceCube Neutrino observatory has reached the level of theoretical expectations of prompt neutrino fluxes, and recent results are presented.
In this paper, after a short introduction to the physics of neutrino telescopes, we will report on first performances of the IceCube detector and a selection of preliminary results obtained from data taken while IceCube operated in a partially comple
ted configuration (22 strings and 40 strings). We will emphasize new analysis methods recently developed for the study of the Southern Hemisphere as well as for extended regions. Based on the long term experience of AMANDA and IceCube, the South Pole ice has proven to be an ideal site for astroparticle physics. New ideas and projects about the future beyond IceCube will conclude this presentation.
We present the current status of the IceTop air shower array on top of the IceCube neutrino detector that IceTop can use as a huge detector of TeV muons. We laos give a brief discussion of different types of air shower events that contain information
on the spectrum and composition of the cosmic rays in a wide energy range.
We report on the first search for extra-terrestrial neutrino-induced cascades in IceCube. The analyzed data were collected in the year 2007 when 22 detector strings were installed and operated. We will discuss the analysis methods used to reconstruct
cascades and to suppress backgrounds. Simulated neutrino signal events with a E-2 energy spectrum, which pass the background rejection criteria, are reconstructed with a resolution dlogE ~ 0.27 in the energy range from ~20 TeV to a few PeV. We present the range of the diffuse flux of extra-terrestrial neutrinos in the cascade channel in IceCube within which we expect to be able to put a limit.
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 objects 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.
The multipole analysis investigates the arrival directions of registered neutrino events in AMANDA-II by a spherical harmonics expansion. The expansion of the expected atmospheric neutrino distribution returns a characteristic set of expansion coeffi
cients. This characteristic spectrum of expansion coefficients can be compared with the expansion coefficients of the experimental data. As atmospheric neutrinos are the dominant background of the search for extraterrestrial neutrinos, the agreement of experimental data and the atmospheric prediction can give evidence for physical neutrino sources or systematic uncertainties of the detector. Astrophysical neutrino signals were simulated and it was shown that they influence the expansion coefficients in a characteristic way. Those simulations are used to analyze deviations between experimental data and Monte Carlo simulations with regard to potential physical reasons. The analysis method was applied on the AMANDA-II neutrino sample measured between 2000 and 2006 and results are presented.
IceCube is a km^3 scale neutrino detector being constructed deep in the Antarctic ice. When complete, IceCube will consist of 4800 optical modules deployed on 80 strings between 1450 and 2450 m of depth. During the 2007-2008 data taking season, 22 st
rings were operational. This configuration is already much larger than previous neutrino telescopes and provides better sensitivity to point sources of high energy (>1 TeV) neutrino emission. Such astrophysical objects are leading candidates for the acceleration of cosmic rays. We describe the IceCube detector and present the methods and results of several recent searches for steady (e.g. AGN) and transient (GRB) point sources.
We describe the design and performance of IceTop, the air shower array on top of the IceCube neutrino detector. After the 2008/09 antarctic summer season both detectors are deployed at almost 3/4 of their design size. With the current IceTop 59 stati
ons we can start the study of showers of energy well above 10$^{17}$ eV. The paper also describes the first results from IceTop and our plans to study the cosmic ray composition using several different types of analysis.
IceCube is a cubic kilometer neutrino telescope under construction at the South Pole. The primary goal is to discover astrophysical sources of high energy neutrinos. We describe the detector and present results on atmospheric muon neutrinos from 2006 data collected with nine detector strings.
