39 results match your criteria: "Particle Astrophysics Center[Affiliation]"

Search for an eV-Scale Sterile Neutrino Using Improved High-Energy ν_{μ} Event Reconstruction in IceCube.

Phys Rev Lett

November 2024

Department of Physics and Wisconsin IceCube Particle Astrophysics Center, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.

Article Synopsis
  • * The study introduces enhanced modeling techniques for neutrino flux and detector response, and it distinguishes between starting (inside) and throughgoing (outside) neutrino interaction events to improve energy resolution.
  • * The findings indicate a best-fit point for the 3+1 model with sin²(2θ_{24})=0.16 and Δm_{41}²=3.5 eV², supporting previous studies while showing consistency with no evidence of sterile neutrinos, as reflected
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Observation of Seven Astrophysical Tau Neutrino Candidates with IceCube.

Phys Rev Lett

April 2024

Department of Physics and Wisconsin IceCube Particle Astrophysics Center, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.

Article Synopsis
  • - The study presents a measurement of astrophysical tau neutrinos using 9.7 years of data from the IceCube observatory, identifying seven candidate events with energies between 20 TeV and 1 PeV.
  • - Convolutional neural networks were used to analyze simulated event images, helping to estimate the parent tau neutrino energy to be around 200 TeV while facing a background of about 0.5 events primarily from non-tau astrophysical neutrinos.
  • - The results confirmed the presence of astrophysical tau neutrinos at a 5σ significance level, aligning with existing IceCube measurements and theoretical predictions regarding neutrino flux and oscillations.
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Search for Boosted Dark Matter in COSINE-100.

Phys Rev Lett

November 2023

Center for Underground Physics, Institute for Basic Science (IBS), Daejeon 34126, Republic of Korea.

We search for energetic electron recoil signals induced by boosted dark matter (BDM) from the galactic center using the COSINE-100 array of NaI(Tl) crystal detectors at the Yangyang Underground Laboratory. The signal would be an excess of events with energies above 4 MeV over the well-understood background. Because no excess of events are observed in a 97.

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Observation of high-energy neutrinos from the Galactic plane.

Science

June 2023

Department of Physics and Laboratory for Particle Physics and Cosmology, Harvard University, Cambridge, MA 02138, USA.

The origin of high-energy cosmic rays, atomic nuclei that continuously impact Earth's atmosphere, is unknown. Because of deflection by interstellar magnetic fields, cosmic rays produced within the Milky Way arrive at Earth from random directions. However, cosmic rays interact with matter near their sources and during propagation, which produces high-energy neutrinos.

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The DAMA/LIBRA collaboration has reported the observation of an annual modulation in the event rate that has been attributed to dark matter interactions over the last two decades. However, even though tremendous efforts to detect similar dark matter interactions were pursued, no definitive evidence has been observed to corroborate the DAMA/LIBRA signal. Many studies assuming various dark matter models have attempted to reconcile DAMA/LIBRA's modulation signals and null results from other experiments, however no clear conclusion can be drawn.

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Search for Unstable Sterile Neutrinos with the IceCube Neutrino Observatory.

Phys Rev Lett

October 2022

Department of Physics and Laboratory for Particle Physics and Cosmology, Harvard University, Cambridge, Massachusetts 02138, USA.

Article Synopsis
  • The study investigates the presence of an unstable sterile neutrino using eight years of atmospheric muon neutrino data collected at the IceCube Neutrino Observatory.
  • Results indicate that both traditional three-neutrino models and 3+1 sterile neutrino models are less favored compared to the unstable sterile neutrino model, but no significant evidence for 3+1 neutrinos with decay was found.
  • The research provides specific parameters for the unstable sterile neutrino model, while also excluding favored regions of the 3+1 model from prior short-baseline oscillation studies.
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Evidence for PeV Proton Acceleration from Fermi-LAT Observations of SNR G106.3+2.7.

Phys Rev Lett

August 2022

Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, California 94305, USA.

The existence of a "knee" at energy ∼1  PeV in the cosmic-ray spectrum suggests the presence of Galactic PeV proton accelerators called "PeVatrons." Supernova remnant (SNR) G106.3+2.

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Strong Constraints on Neutrino Nonstandard Interactions from TeV-Scale ν_{μ} Disappearance at IceCube.

Phys Rev Lett

July 2022

Department of Physics and Laboratory for Particle Physics and Cosmology, Harvard University, Cambridge, Massachusetts 02138, USA.

We report a search for nonstandard neutrino interactions (NSI) using eight years of TeV-scale atmospheric muon neutrino data from the IceCube Neutrino Observatory. By reconstructing incident energies and zenith angles for atmospheric neutrino events, this analysis presents unified confidence intervals for the NSI parameter ε_{μτ}. The best-fit value is consistent with no NSI at a p value of 25.

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Tau Appearance from High-Energy Neutrino Interactions.

Phys Rev Lett

April 2022

Department of Physics and Laboratory for Particle Physics and Cosmology, Harvard University, Cambridge, Massachusetts 02138, USA.

High-energy muon and electron neutrinos yield a non-negligible flux of tau neutrinos as they propagate through Earth. In this Letter, we address the impact of this additional component in the PeV and EeV energy regimes for the first time. Above 300 TeV, this contribution is predicted to be significantly larger than the atmospheric background, and it alters current and future neutrino telescopes' capabilities to discover a cosmic tau-neutrino flux.

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Search for Relativistic Magnetic Monopoles with Eight Years of IceCube Data.

Phys Rev Lett

February 2022

Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794-3800, USA.

We present an all-sky 90% confidence level upper limit on the cosmic flux of relativistic magnetic monopoles using 2886 days of IceCube data. The analysis was optimized for monopole speeds between 0.750c and 0.

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We present new constraints on dark matter interactions using 1.7 years of COSINE-100 data. The COSINE-100 experiment, consisting of 106 kg of tallium-doped sodium iodide [NaI(Tl)] target material, is aimed to test DAMA’s claim of dark matter observation using the same NaI(Tl) detectors.

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The results of a 3+1 sterile neutrino search using eight years of data from the IceCube Neutrino Observatory are presented. A total of 305 735 muon neutrino events are analyzed in reconstructed energy-zenith space to test for signatures of a matter-enhanced oscillation that would occur given a sterile neutrino state with a mass-squared differences between 0.01 and 100  eV^{2}.

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We report on the first measurement of the astrophysical neutrino flux using particle showers (cascades) in IceCube data from 2010-2015. Assuming standard oscillations, the astrophysical neutrinos in this dedicated cascade sample are dominated (∼90%) by electron and tau flavors. The flux, observed in the sensitive energy range from 16 TeV to 2.

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This Letter presents the results from pointlike neutrino source searches using ten years of IceCube data collected between April 6, 2008 and July 10, 2018. We evaluate the significance of an astrophysical signal from a pointlike source looking for an excess of clustered neutrino events with energies typically above ∼1  TeV among the background of atmospheric muons and neutrinos. We perform a full-sky scan, a search within a selected source catalog, a catalog population study, and three stacked Galactic catalog searches.

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We present new constraints on the dark matter-induced annual modulation signal using 1.7 years of COSINE-100 data with a total exposure of 97.7 kg yr.

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A search for inelastic boosted dark matter (IBDM) using the COSINE-100 detector with 59.5 days of data is presented. This relativistic dark matter is theorized to interact with the target material through inelastic scattering with electrons, creating a heavier state that subsequently produces standard model particles, such as an electron-positron pair.

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Constraints on Minute-Scale Transient Astrophysical Neutrino Sources.

Phys Rev Lett

February 2019

Department of Physics and Wisconsin IceCube Particle Astrophysics Center, University of Wisconsin, Madison, Wisconsin 53706, USA.

High-energy neutrino emission has been predicted for several short-lived astrophysical transients including gamma-ray bursts (GRBs), core-collapse supernovae with choked jets, and neutron star mergers. IceCube's optical and x-ray follow-up program searches for such transient sources by looking for two or more muon neutrino candidates in directional coincidence and arriving within 100 s. The measured rate of neutrino alerts is consistent with the expected rate of chance coincidences of atmospheric background events and no likely electromagnetic counterparts have been identified in Swift follow-up observations.

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Publisher Correction: Very-high-energy particle acceleration powered by the jets of the microquasar SS 433.

Nature

December 2018

Physics and Theoretical Divisions, Los Alamos National Laboratory, Los Alamos, NM, USA.

In this Letter, owing to a production error, the penultimate version of the PDF was published. The HTML version was always correct. The PDF has been corrected online.

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Very-high-energy particle acceleration powered by the jets of the microquasar SS 433.

Nature

October 2018

Physics and Theoretical Divisions, Los Alamos National Laboratory, Los Alamos, NM, USA.

SS 433 is a binary system containing a supergiant star that is overflowing its Roche lobe with matter accreting onto a compact object (either a black hole or neutron star). Two jets of ionized matter with a bulk velocity of approximately 0.26c (where c is the speed of light in vacuum) extend from the binary, perpendicular to the line of sight, and terminate inside W50, a supernova remnant that is being distorted by the jets.

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Measurement of Atmospheric Neutrino Oscillations at 6-56 GeV with IceCube DeepCore.

Phys Rev Lett

February 2018

Oskar Klein Centre and Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden.

We present a measurement of the atmospheric neutrino oscillation parameters using three years of data from the IceCube Neutrino Observatory. The DeepCore infill array in the center of IceCube enables the detection and reconstruction of neutrinos produced by the interaction of cosmic rays in Earth's atmosphere at energies as low as ∼5  GeV. That energy threshold permits measurements of muon neutrino disappearance, over a range of baselines up to the diameter of the Earth, probing the same range of L/E_{ν} as long-baseline experiments but with substantially higher-energy neutrinos.

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Background model for the NaI(Tl) crystals in COSINE-100.

Eur Phys J C Part Fields

June 2018

8Center for Underground Physics, Institute for Basic Science (IBS), Daejeon, 34126 Republic of Korea.

The COSINE-100 dark matter search experiment is an array of NaI(Tl) crystal detectors located in the Yangyang Underground Laboratory (Y2L). To understand measured backgrounds in the NaI(Tl) crystals we have performed Monte Carlo simulations using the Geant4 toolkit and developed background models for each crystal that consider contributions from both internal and external sources, including cosmogenic nuclides. The background models are based on comparisons of measurement data with Monte Carlo simulations that are guided by a campaign of material assays and are used to evaluate backgrounds and identify their sources.

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Search for neutrinos from decaying dark matter with IceCube: IceCube Collaboration.

Eur Phys J C Part Fields

October 2018

31Department of Physics and Wisconsin IceCube Particle Astrophysics Center, University of Wisconsin, Madison, WI 53706 USA.

With the observation of high-energy astrophysical neutrinos by the IceCube Neutrino Observatory, interest has risen in models of PeV-mass decaying dark matter particles to explain the observed flux. We present two dedicated experimental analyses to test this hypothesis. One analysis uses 6 years of IceCube data focusing on muon neutrino 'track' events from the Northern Hemisphere, while the second analysis uses 2 years of 'cascade' events from the full sky.

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We show that the high-energy cosmic neutrinos seen by the IceCube Neutrino Observatory can be used to probe interactions between neutrinos and the dark sector that cannot be reached by current cosmological methods. The origin of the observed neutrinos is still unknown, and their arrival directions are compatible with an isotropic distribution. This observation, together with dedicated studies of Galactic plane correlations, suggests a predominantly extragalactic origin.

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Measurement of the energy spectrum with IceCube-79: IceCube Collaboration.

Eur Phys J C Part Fields

October 2017

42Department of Physics, Oskar Klein Centre, Stockholm University, 10691 Stockholm, Sweden.

IceCube is a neutrino observatory deployed in the glacial ice at the geographic South Pole. The 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.

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We report constraints on the sources of ultrahigh-energy cosmic rays (UHECRs) above 10^{9}  GeV, based on an analysis of seven years of IceCube data. This analysis efficiently selects very high- energy neutrino-induced events which have deposited energies from 5×10^{5}  GeV to above 10^{11}  GeV. Two neutrino-induced events with an estimated deposited energy of (2.

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