Research – Page 20

Searches for time-dependent neutrino sources with IceCube

Posted on March 3, 2015 by Silvia Bravo

Searches with IceCube have so far persistently shown us that more data is needed to reveal the first cosmic ray source. But IceCube researchers are convinced that success also requires a resolute determination to exploit IceCube data in every possible manner. In a new study submitted today to the Astrophysical Journal, the collaboration presents a search for time-dependent astrophysical neutrino sources that did not find any evidence for their existence. The study did however make it possible to set upper limits on the neutrino flux from several source candidates and has proven IceCube’s capabilities for long-term monitoring of sources triggered by multiwavelength information from several experiments. […]

Measuring the flavor ratio of astrophysical neutrinos

Posted on February 12, 2015 by Silvia Bravo

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In a new measurement of the flavor ratio of astrophysical neutrinos, submitted today to Physical Review Letters, the IceCube Collaboration has found good agreement with the standard source model. The collaboration also sets limits on nonstandard flavor compositions, which could be a signature for new physics in the neutrino sector, such as neutrino decay or sterile neutrinos. […]

Gamma-ray bursts are not main contributors to the astrophysical neutrino flux in IceCube

Posted on December 22, 2014 by Silvia Bravo

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Gamma-ray bursts (GRBs) were once the most promising candidate source of ultra-high-energy cosmic rays (UHECRs). They release extremely large amounts of energy in short periods of time, so if they could accelerate protons as they do electrons, then GRBs could account for most of the observed UHECRs. […]

Atmospheric neutrino oscillations measured with three years of IceCube data

Posted on October 28, 2014 by Silvia Bravo

Last year, an initial measurement of the neutrino oscillation parameters was a hint that IceCube could become an important detector for studying neutrino oscillations. Today, the IceCube Collaboration has submitted new results to Physical Review Letters that present an improved measurement of the oscillation parameters, via atmospheric muon neutrino disappearance, which is compatible and comparable in precision to those of dedicated oscillation experiments such as MINOS, T2K or Super-Kamiokande. […]

More on astrophysical neutrinos yet no track of charmed mesons

Posted on October 7, 2014 by Silvia Bravo

The IceCube Collaboration has expanded the search for neutrino interactions in IceCube, lowering the range of deposited energy down to 1 TeV. The goal was a better understanding of the different contributions to the neutrino flux in IceCube and hopefully to measure the charmed-meson component for the first time. The results of this study have been submitted today to Physical Review D. […]

An improved measurement of the atmospheric neutrino flux in IceCube

Posted on September 17, 2014 by Silvia Bravo

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The IceCube Collaboration has submitted a paper today to the European Physical Journal C describing a new analysis scheme for the measurement of the atmospheric neutrino spectrum with the IceCube detector. […]

A search for faint neutrino point sources in IceCube

Posted on August 5, 2014 by Silvia Bravo

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In a new analysis by the IceCube Collaboration, a search for faint point sources, by looking for small-scale anisotropies in the diffuse neutrino flux, was found to be consistent with the background expectation. These results have just been submitted to Astroparticle Physics. […]

Multimessenger search for cosmic sources by initial LIGO-Virgo and IceCube

Posted on July 7, 2014 by Silvia Bravo

In a joint analysis by the IceCube, LIGO and Virgo collaborations to be submitted to the journal Physical Review D, researchers aimed to identify GW events and high-energy neutrinos that could originate from the same astrophysical source and to determine their joint significance. No significant coincident events were found, but the search allowed researchers to derive upper limits on the rate of joint sources for a range of source emission parameters. […]

A search for dark matter in the galactic halo

Posted on June 27, 2014 by Silvia Bravo

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The quest for galactic halo dark matter includes high-energy neutrino searches that might be produced by the self-annihilation of dark matter particles in our galaxy. If this is the case, IceCube should observe a characteristic anisotropy in the neutrino flux due to the additional dark-matter induced neutrinos. So far, the IceCube Collaboration has not found any significant deviation from the background expectation, following new results that have been submitted today to The European Physical Journal C. […]

Search for neutrino emission from extended and point-like astrophysical neutrino sources with IceCube

Posted on June 26, 2014 by Silvia Bravo

The IceCube Collaboration presents several searches for extended and point-like astrophysical neutrino sources using four years of data. No evidence of neutrino emission has been found yet, but a few models have been ruled out. This research has been submitted today to The Astrophysical Journal. […]