Measurement of the νμ energy spectrum with IceCube-79

This work is licensed under a Creative Commons Attribution 4.0 International License.IceCube is a neutrino observatory deployed in the glacial ice at the geographic South Pole. The νμ energy unfolding described in this paper is based on data taken with IceCube in its 79-string configuration. A sample of muon neutrino charged-current interactions with a purity of 99.5% was selected by means of a multivariate classification process based on machine learning. The subsequent unfolding was performed using the software truee. The resulting spectrum covers an Eν-range of more than four orders of magnitude from 125 GeV to 3.2 PeV. Compared to the Honda atmospheric neutrino flux model, the energy spectrum shows an excess of more than 1.9σ in four adjacent bins for neutrino energies Eν≥177.8TeV. The obtained spectrum is fully compatible with previous measurements of the atmospheric neutrino flux and recent IceCube measurements of a flux of high-energy astrophysical neutrinos

Detection of the Temporal Variation of the Sun's Cosmic Ray Shadow with the IceCube Detector

We report on the observation of a deficit in the cosmic ray flux from the directions of the Moon and Sun with five years of data taken by the IceCube Neutrino Observatory. Between 2010 May and 2011 May the IceCube detector operated with 79 strings deployed in the glacial ice at the South Pole, and with 86 strings between 2011 May and 2015 May. A binned analysis is used to measure the relative deficit and significance of the cosmic ray shadows. Both the cosmic ray Moon and Sun shadows are detected with high statistical significance (>10σ) for each year. The results for the Moon shadow are consistent with previous analyses and verify the stability of the IceCube detector over time. This work represents the first observation of the Sun shadow with the IceCube detector. We show that the cosmic ray shadow of the Sun varies with time. These results make it possible to study cosmic ray transport near the Sun with future data from IceCube

Erratum to: Search for annihilating dark matter in the Sun with 3 years of IceCube data

This work is licensed under a Creative Commons Attribution 4.0 International License

Erratum to: Search for non-relativistic magnetic monopoles with IceCube

This work is licensed under a Creative Commons Attribution 4.0 International License

Cosmic ray spectrum and composition from PeV to EeV using 3 years of data from IceTop and IceCube

We report on measurements of the all-particle cosmic ray energy spectrum and composition in the PeV to EeV energy range using 3 years of data from the IceCube Neutrino Observatory. The IceTop detector measures cosmic ray induced air showers on the surface of the ice, from which the energy spectrum of cosmic rays is determined by making additional assumptions about the mass composition. A separate measurement is performed when IceTop data are analyzed in coincidence with the high-energy muon energy loss information from the deep in-ice IceCube detector. In this measurement, both the spectrum and the mass composition of the primary cosmic rays are simultaneously reconstructed using a neural network trained on observables from both detectors. The performance and relative advantages of these two distinct analyses are discussed, including the systematic uncertainties and the dependence on the hadronic interaction models, and both all-particle spectra as well as individual spectra for elemental groups are presented

Measurement of atmospheric tau neutrino appearance with IceCube DeepCore

This work is licensed under a Creative Commons Attribution 4.0 International License.We present a measurement of atmospheric tau neutrino appearance from oscillations with three years of data from the DeepCore subarray of the IceCube Neutrino Observatory. This analysis uses atmospheric neutrinos from the full sky with reconstructed energies between 5.6 and 56 GeV to search for a statistical excess of cascadelike neutrino events which are the signature of ντ interactions. For CC + NC (CC-only) interactions, we measure the tau neutrino normalization to be 0.73 +0.30 −0.24 (0.57 +0.36 −0.30) and exclude the absence of tau neutrino oscillations at a significance of 3.2σ (2.0σ) These results are consistent with, and of similar precision to, a confirmatory IceCube analysis also presented, as well as measurements performed by other experiments

LUNASKA simultaneous neutrino searches with multiple telescopes

The most sensitive method for detecting neutrinos at the very highest energies is the lunar Cherenkov technique, which employs the Moon as a target volume, using conventional radio telescopes to monitor it for nanosecond-scale pulses of Cherenkov radiation from particle cascades in its regolith. Multiple-antenna radio telescopes are difficult to effectively combine into a single detector for this purpose, while single antennas are more susceptible to false events from radio interference, which must be reliably excluded for a credible detection to be made. We describe our progress in excluding such interference in our observations with the single-antenna Parkes radio telescope, and our most recent experiment (taking place the week before the ICRC) using it in conjunction with the Australia Telescope Compact Array, exploiting the advantages of both types of telescope.Comment: 4 pages, 4 figures, in Proceedings of the 32nd International Cosmic Ray Conference (Beijing 2011

Multimessenger Search for Sources of Gravitational Waves and High-Energy Neutrinos: Initial Results for LIGO-Virgo and IceCube

We report the results of a multimessenger search for coincident signals from the LIGO and Virgo gravitational-wave observatories and the partially completed IceCube high-energy neutrino detector, including periods of joint operation between 2007-2010. These include parts of the 2005-2007 run and the 2009-2010 run for LIGO-Virgo, and IceCube\u27s observation periods with 22, 59 and 79 strings. We find no significant coincident events, and use the search results to derive upper limits on the rate of joint sources for a range of source emission parameters. For the optimistic assumption of gravitational-wave emission energy of 10-2M⊙c2 at ∼150Hz with ∼60ms duration, and high-energy neutrino emission of 1051 erg comparable to the isotropic gamma-ray energy of gamma-ray bursts, we limit the source rate below 1.6x10-2Mpc-3yr-1. We also examine how combining information from gravitational waves and neutrinos will aid discovery in the advanced gravitational-wave detector era

The mantle source of lamproites from Torre Alfina, Italy: Evidence from melt inclusions in olivine

The complex post-collisional subduction setting of peninsular Italy, in the central-western Mediterranean region, has given rise to an extremely diverse spectrum of potassium-rich volcanic rocks. The most primitive of these products show trace-element and radiogenic isotope signatures that point to melt derivation from upper mantle domains affected by metasomatism associated with sediment recycling. The style and extent of this metasomatism, and the metasomatic agents responsible for this modification, seem to differ significantly throughout the Italian peninsula. The lamproites of the Tuscan magmatic province, central Italy, are a peculiar and rare example of rocks that require extensive source modification that is not yet well-understood. These rocks are ultrapotassic and mafic in composition and have high compatible trace-element contents. Although bulk-rock compositions have been used to interrogate their petrogenesis, bulk lavas do not reflect the full heterogeneity of their mantle source. Here, we study the geochemistry of melt inclusions in forsterite-rich olivine, which in contrast to their host lavas are snapshots of near-primary melts that have bypassed modification on their way to the surface. The olivines (Fo88-93) from the studied lamproites of Torre Alfina host melt inclusions with major- and trace-element compositions that define two distinct groups. The first is marked by lower SiO2 (47–51 vs. 50–60 wt%) and higher K2O (11–17 vs. 8–14 wt%), CaO (3.5–6 vs. 1.5–5 wt%), TiO2 (1.8–2.4 vs. 0.3–1.8 wt%), P2O5 (1.0–1.7 vs. 0.1–0.9 wt%) and different trace-element contents. Group-1 melts are generally similar to other Tuscan lamproites, whereas group-2 melts are, in terms of trace elements, more akin to the Tuscan high-K calc-alkaline mafic rocks. We interpret these two melt types to originate from a sediment-metasomatised mantle source, which is characterised by distinct (vein) lithologies arising from superimposed metasomatic events. The Sr-Nd-Pb isotope compositions of a subset of the studied inclusions, analysed by wet chemistry and TIMS techniques, will be presented to further constrain the mantle source of these unusual and hitherto unreported primitive melt compositions, and ultimately better understand lamproite petrogenesis