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Danninger, Matthias
Publications (10 of 73) Show all publications
Ahrens, M., Bohm, C., Danninger, M., Dumm, J. P., Edsjö, J., Finley, C., . . . Zoll, M. (2016). Improved limits on dark matter annihilation in the Sun with the 79-string IceCube detector and implications for supersymmetry. Journal of Cosmology and Astroparticle Physics (4), Article ID 022.
Open this publication in new window or tab >>Improved limits on dark matter annihilation in the Sun with the 79-string IceCube detector and implications for supersymmetry
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2016 (English)In: Journal of Cosmology and Astroparticle Physics, E-ISSN 1475-7516, no 4, article id 022Article in journal (Refereed) Published
Abstract [en]

We present an improved event-level likelihood formalism for including neutrino telescope data in global fits to new physics. We derive limits on spin-dependent dark matter-proton scattering by employing the new formalism in a re-analysis of data from the 79-string IceCube search for dark matter annihilation in the Sun, including explicit energy information for each event. The new analysis excludes a number of models in the weak-scale minimal supersymmetric standard model (MSSM) for the first time. This work is accompanied by the public release of the 79-string IceCube data, as well as an associated computer code for applying the new likelihood to arbitrary dark matter models.

Keywords
dark matter experiments, dark matter theory, neutrino experiments
National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-140379 (URN)10.1088/1475-7516/2016/04/022 (DOI)000393286400001 ()
Available from: 2017-03-27 Created: 2017-03-27 Last updated: 2023-03-28Bibliographically approved
Ahrens, M., Bohm, C., Danninger, M., Finley, C., Flis, S., Hulth, P. O., . . . Zoll, M. (2015). Atmospheric and astrophysical neutrinos above 1 TeV interacting in IceCube. Physical Review D, 91(2), 022001
Open this publication in new window or tab >>Atmospheric and astrophysical neutrinos above 1 TeV interacting in IceCube
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2015 (English)In: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 91, no 2, p. 022001-Article in journal (Refereed) Published
Abstract [en]

The IceCube Neutrino Observatory was designed primarily to search for high-energy (TeV-PeV) neutLrinos produced in distant astrophysical objects. A search for. greater than or similar to 100 TeV neutrinos interacting inside the instrumented volume has recently provided evidence for an isotropic flux of such neutrinos. At lower energies, IceCube collects large numbers of neutrinos from the weak decays of mesons in cosmic-ray air showers. Here we present the results of a search for neutrino interactions inside IceCube's instrumented volume between 1 TeV and 1 PeV in 641 days of data taken from 2010-2012, lowering the energy threshold for neutrinos from the southern sky below 10 TeV for the first time, far below the threshold of the previous high-energy analysis. Astrophysical neutrinos remain the dominant component in the southern sky down to a deposited energy of 10 TeV. From these data we derive new constraints on the diffuse astrophysical neutrino spectrum, Phi(v) = 2.06(-0.3)(+0.4) x 10(-18) (E-v = 10(5) GeV)-2.46 +/- 0.12GeV-1 cm(-2) sr(-1) s(-1) for 25 TeV < E-v < 1.4 PeV, as well as the strongest upper limit yet on the flux of neutrinos from charmed-meson decay in the atmosphere, 1.52 times the benchmark theoretical prediction used in previous IceCube results at 90% confidence.

National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:su:diva-113953 (URN)10.1103/PhysRevD.91.022001 (DOI)000347924700001 ()2-s2.0-84926352976 (Scopus ID)
Note

AuthorCount:305;

Available from: 2015-02-23 Created: 2015-02-16 Last updated: 2022-10-14Bibliographically approved
Ahrens, M., Bohm, C., Danninger, M., Finley, C., Flis, S., Hulth, P. O., . . . Zoll, M. (2015). Development of a general analysis and unfolding scheme and its application to measure the energy spectrum of atmospheric neutrinos with IceCube. European Physical Journal C, 75(3), Article ID 116.
Open this publication in new window or tab >>Development of a general analysis and unfolding scheme and its application to measure the energy spectrum of atmospheric neutrinos with IceCube
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2015 (English)In: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 75, no 3, article id 116Article in journal (Refereed) Published
Abstract [en]

We present the development and application of a generic analysis scheme for the measurement of neutrino spectra with the IceCube detector. This scheme is based on regularized unfolding, preceded by an event selection which uses a Minimum Redundancy Maximum Relevance algorithm to select the relevant variables and a random forest for the classification of events. The analysis has been developed using IceCube data from the 59-string configuration of the detector. 27,771 neutrino candidates were detected in 346 days of livetime. A rejection of 99.9999 % of the atmospheric muon background is achieved. The energy spectrum of the atmospheric neutrino flux is obtained using the TRUEE unfolding program. The unfolded spectrum of atmospheric muon neutrinos covers an energy range from 100 GeV to 1 PeV. Compared to the previous measurement using the detector in the 40-string configuration, the analysis presented here, extends the upper end of the atmospheric neutrino spectrum by more than a factor of two, reaching an energy region that has not been previously accessed by spectral measurements.

National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-119009 (URN)10.1140/epjc/s10052-015-3330-z (DOI)000355666000004 ()
Available from: 2015-07-28 Created: 2015-07-24 Last updated: 2022-03-23Bibliographically approved
Ahrens, M., Bohm, C., Danninger, M., Finley, C., Flis, S., Hulth, P. O., . . . Zoll, M. (2015). Multipole analysis of IceCube data to search for dark matter accumulated in the Galactic halo. European Physical Journal C, 75(1), Article ID 20.
Open this publication in new window or tab >>Multipole analysis of IceCube data to search for dark matter accumulated in the Galactic halo
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2015 (English)In: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 75, no 1, article id 20Article in journal (Refereed) Published
Abstract [en]

Dark matter which is bound in the Galactic halo might self-annihilate and produce a flux of stable final state particles, e. g. high energy neutrinos. These neutrinos can be detected with IceCube, a cubic-kilometer sized Cherenkov detector. Given IceCube's large field of view, a characteristic anisotropy of the additional neutrino flux is expected. In this paper we describe a multipole method to search for such a large-scale anisotropy in IceCube data. This method uses the expansion coefficients of a multipole expansion of neutrino arrival directions and incorporates signal-specific weights for each expansion coefficient. We apply the technique to a high-purity muon neutrino sample from the Northern Hemisphere. The final result is compatible with the null-hypothesis. As no signal was observed, we present limits on the self-annihilation cross-section averaged over the relative velocity distribution <sigma(A)v > down to 1.9x10(-23) cm(3) s(-1) for a dark matter particle mass of 700-1,000 GeV and direct annihilation into nu(nu) over bar. The resulting exclusion limits come close to exclusion limits from gamma-ray experiments, that focus on the outer Galactic halo, for high dark matter masses of a few TeV and hard annihilation channels.

National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-115457 (URN)10.1140/epjc/s10052-014-3224-5 (DOI)000348992100002 ()
Note

AuthorCount:301;

Available from: 2015-03-27 Created: 2015-03-24 Last updated: 2022-03-23Bibliographically approved
Aartsen, M. G., Ackermann, M., Adams, J., Aguilar, J. A., Ahlers, M., Ahrens, M., . . . Zoll, M. (2015). Searches for small-scale anisotropies from neutrino point sources with three years of IceCube data. Astroparticle physics, 66, 39-52
Open this publication in new window or tab >>Searches for small-scale anisotropies from neutrino point sources with three years of IceCube data
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2015 (English)In: Astroparticle physics, ISSN 0927-6505, E-ISSN 1873-2852, Vol. 66, p. 39-52Article in journal (Refereed) Published
Abstract [en]

Recently, IceCube found evidence for a diffuse signal of astrophysical neutrinos in an energy range of similar to 60 TeV to the PeV-scale [1]. The origin of those events, being a key to understanding the origin of cosmic rays, is still an unsolved question. So far, analyses have not succeeded to resolve the diffuse signal into point-like sources. Searches including a maximum-likelihood-ratio test, based on the reconstructed directions and energies of the detected down- and up-going neutrino candidates, were also performed on IceCube data leading to the exclusion of bright point sources. In this paper, we present two methods to search for faint neutrino point sources in three years of IceCube data, taken between 2008 and 2011. The first method is an autocorrelation test, applied separately to the northern and southern sky. The second method is a multipole analysis, which expands the measured data in the northern hemisphere into spherical harmonics and uses the resulting expansion coefficients to separate signal from background. With both methods, the results are consistent with the background expectation with a slightly more sparse spatial distribution, corresponding to an underfluctuation. Depending on the assumed number of sources, the resulting upper limit on the flux per source in the northern hemisphere for an E-2 energy spectrum ranges from similar to 1.5. 10(-8) GeV/cm(2) s(-1), in the case of one assumed source, to similar to 4. 10(-10) GeV/cm(2) s(-1), in the case of 3500 assumed sources.

Keywords
Extraterrestrial neutrinos, Astrophysical neutrinos, Point sources, IceCube, 2pt-correlation, Multipole analysis
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:su:diva-131411 (URN)10.1016/j.astropartphys.2015.01.001 (DOI)000352045100006 ()2-s2.0-84983517813 (Scopus ID)
Available from: 2016-06-17 Created: 2016-06-17 Last updated: 2022-10-14Bibliographically approved
Bohm, C., Danninger, M., Finley, C., Flis, S., Hulth, P. O., Hultqvist, K., . . . Zoll, M. (2015). The IceProd framework: Distributed data processing for the IceCube neutrino observatory. Journal of Parallel and Distributed Computing, 75, 198-211
Open this publication in new window or tab >>The IceProd framework: Distributed data processing for the IceCube neutrino observatory
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2015 (English)In: Journal of Parallel and Distributed Computing, ISSN 0743-7315, E-ISSN 1096-0848, Vol. 75, p. 198-211Article in journal (Refereed) Published
Abstract [en]

IceCube is a one-gigaton instrument located at the geographic South Pole, designed to detect cosmic neutrinos, identify the particle nature of dark matter, and study high-energy neutrinos themselves. Simulation of the IceCube detector and processing of data require a significant amount of computational resources. This paper presents the first detailed description of IceProd, a lightweight distributed management system designed to meet these requirements. It is driven by a central database in order to manage mass production of simulations and analysis of data produced by the IceCube detector. IceProd runs as a separate layer on top of other middleware and can take advantage of a variety of computing resources, including grids and batch systems such as CREAM, HTCondor, and PBS. This is accomplished by a set of dedicated daemons that process job submission in a coordinated fashion through the use of middleware plugins that serve to abstract the details of job submission and job management from the framework.

Keywords
Data management, Grid computing, Monitoring, Distributed computing
National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-112890 (URN)10.1016/j.jpdc.2014.08.001 (DOI)000346552500017 ()2-s2.0-84915776438 (Scopus ID)
Note

AuthorCount:287;

Available from: 2015-01-25 Created: 2015-01-19 Last updated: 2022-10-17Bibliographically approved
Bohm, C., Danninger, M., Finley, C., Flis, S., Hulth, P.-O., Hultqvist, K., . . . Zoll, M. (2014). Energy reconstruction methods in the IceCube neutrino telescope. Journal of Instrumentation, 9, P03009
Open this publication in new window or tab >>Energy reconstruction methods in the IceCube neutrino telescope
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2014 (English)In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 9, p. P03009-Article in journal (Refereed) Published
Abstract [en]

Accurate measurement of neutrino energies is essential to many of the scientific goals of large-volume neutrino telescopes. The fundamental observable in such detectors is the Cherenkov light produced by the transit through a medium of charged particles created in neutrino interactions. The amount of light emitted is proportional to the deposited energy, which is approximately equal to the neutrino energy for v(e) and v(mu) charged-current interactions and can be used to set a lower bound on neutrino energies and to measure neutrino spectra statistically in other channels. Here we describe methods and performance of reconstructing charged-particle energies and topologies from the observed Cherenkov light yield, including techniques to measure the energies of uncontained muon tracks, achieving average uncertainties in electromagnetic-equivalent deposited energy of similar to 15% above 10 TeV.

Keywords
Cherenkov detectors, dE/dx detectors, Neutrino detectors, Performance of High Energy Physics Detectors
National Category
Accelerator Physics and Instrumentation
Identifiers
urn:nbn:se:su:diva-105251 (URN)10.1088/1748-0221/9/03/P03009 (DOI)000336123200069 ()2-s2.0-84896909834 (Scopus ID)
Note

AuthorCount:287;

Available from: 2014-06-25 Created: 2014-06-24 Last updated: 2022-10-10Bibliographically approved
Bohm, C., Danninger, M., Finley, C., Flis, S., Hulth, P.-O., Hultqvist, K., . . . Zoll, M. (2014). Improvement in fast particle track reconstruction with robust statistics. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 736, 143-149
Open this publication in new window or tab >>Improvement in fast particle track reconstruction with robust statistics
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2014 (English)In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 736, p. 143-149Article in journal (Refereed) Published
Abstract [en]

The IceCube project has transformed 1 km(3) of deep natural Antarctic ice into a Cherenkov detector Muon neutrinos are detected and their direction is inferred by mapping the light produced by the secondary muon track inside the volume instrumented with photomultipliers. Reconstructing the muon track from the observed light is challenging due to noise, light scattering in the ice medium, and the possibility of simultaneously having multiple muons inside the detector, resulting from the large flux of cosmic ray muons. This paper describes work on two problems: (1) the truck reconstruction problem, in which, given a set of observations, the goal is to recover the track of a muon; and (2) the coincident event problem, which is to determine how many muons are active in the detector during a time window. Rather than solving these problems by developing more complex physical models that are applied at later stages of the analysis, our approach is to augment the detector's early reconstruction with data filters and robust statistical techniques. These can be implemented at the level of on-line reconstruction and, therefore, improve all subsequent reconstructions. Using the metric of median angular resolution, a standard metric for track reconstruction, we improve the accuracy in the initial reconstruction direction by 13%. We also present improvements in measuring the number of muons in coincident events: we can accurately determine the number of muons 98% of the time.

Keywords
Ice Cube, Track reconstruction, Neutrino telescope, Neutrino astrophysics, Robust statistics
National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-100648 (URN)10.1016/j.nima.2013.10.074 (DOI)000329404000019 ()2-s2.0-84889009799 (Scopus ID)
Note

AuthorCount:279;

Available from: 2014-02-14 Created: 2014-02-10 Last updated: 2022-10-12Bibliographically approved
Ahrens, M., Bohm, C., Danninger, M., Finley, C., Flis, S., Hulth, P.-O., . . . Zoll, M. (2014). Multimessenger search for sources of gravitational waves and high-energy neutrinos: Initial results for LIGO-Virgo and IceCube. Physical Review D, 90(10)
Open this publication in new window or tab >>Multimessenger search for sources of gravitational waves and high-energy neutrinos: Initial results for LIGO-Virgo and IceCube
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2014 (English)In: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 90, no 10Article in journal (Refereed) Published
Abstract [en]

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's 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(-2) M(circle dot)c(2) at similar to 150 Hz with similar to 60 ms 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 1.6 x 10(-2) Mpc(-3) yr(-1). We also examine how combining information from gravitational waves and neutrinos will aid discovery in the advanced gravitational-wave detector era.

National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-111919 (URN)10.1103/PhysRevD.90.102002 (DOI)000345691400001 ()2-s2.0-84911906757 (Scopus ID)
Note

AuthorCount:1186;

Available from: 2015-01-09 Created: 2015-01-08 Last updated: 2022-10-13Bibliographically approved
Ahrens, M., Bohm, C., Danninger, M., Finley, C., Flis, S., Hulth, P.-O., . . . Zoll, M. (2014). Observation of High-Energy Astrophysical Neutrinos in Three Years of IceCube Data. Physical Review Letters, 113(10), 101101
Open this publication in new window or tab >>Observation of High-Energy Astrophysical Neutrinos in Three Years of IceCube Data
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2014 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 113, no 10, p. 101101-Article in journal (Refereed) Published
Abstract [en]

A search for high-energy neutrinos interacting within the IceCube detector between 2010 and 2012 provided the first evidence for a high-energy neutrino flux of extraterrestrial origin. Results from an analysis using the same methods with a third year (2012-2013) of data from the complete IceCube detector are consistent with the previously reported astrophysical flux in the 100 TeV-PeV range at the level of 10(-8) GeV cm(-2) s(-1) sr(-1) per flavor and reject a purely atmospheric explanation for the combined three-year data at 5.7 sigma. The data are consistent with expectations for equal fluxes of all three neutrino flavors and with isotropic arrival directions, suggesting either numerous or spatially extended sources. The three-year data set, with a live time of 988 days, contains a total of 37 neutrino candidate events with deposited energies ranging from 30 to 2000 TeV. The 2000-TeV event is the highest-energy neutrino interaction ever observed.

National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-107789 (URN)10.1103/PhysRevLett.113.101101 (DOI)000341248100003 ()2-s2.0-84907215917 (Scopus ID)
Note

AuthorCount:297;

Available from: 2014-10-06 Created: 2014-09-29 Last updated: 2022-10-13Bibliographically approved
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