arXiv subjects

D. Z. Besson

Publications and source records attributed to D. Z. Besson.

At least 127 records · Page 7Linked to original sources

arXiv2021

All-flavor constraints on nonstandard neutrino interactions and generalized matter potential with three years of IceCube DeepCore data

We report constraints on nonstandard neutrino interactions (NSI) from the observation of atmospheric neutrinos with IceCube, limiting all individual coupling strengths from a single dataset. Furthermore, IceCube is the first experiment to constrain flavor-violating and nonuniversal couplings simultaneously. Hypothetical NSI are generically expected to arise due to the exchange of a new heavy mediator particle. Neutrinos propagating in matter scatter off fermions in the forward direction with negligible momentum transfer. Hence the study of the matter effect on neutrinos propagating in the Earth is sensitive to NSI independently of the energy scale of new physics. We present constraints on NSI obtained with an all-flavor event sample of atmospheric neutrinos based on three years of IceCube DeepCore data. The analysis uses neutrinos arriving from all directions, with reconstructed energies between 5.6 GeV and 100 GeV. We report constraints on the individual NSI coupling strengths considered singly, allowing for complex phases in the case of flavor-violating couplings. This demonstrates that IceCube is sensitive to the full NSI flavor structure at a level competitive with limits from the global analysis of all other experiments. In addition, we investigate a generalized matter potential, whose overall scale and flavor structure are also constrained.

hep-ex↗

arXiv2021

An eV-scale sterile neutrino search using eight years of atmospheric muon neutrino data from the IceCube Neutrino Observatory

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\,eV$^2$ and 100\,eV$^2$. The best-fit point is found to be at $\sin^2(2θ_{24})=0.10$ and $Δm_{41}^2 = 4.5{\rm eV}^2$, which is consistent with the no sterile neutrino hypothesis with a p-value of 8.0\%.

hep-ex↗

arXiv2021

The Payload for Ultrahigh Energy Observations (PUEO): A White Paper

The Payload for Ultrahigh Energy Observations (PUEO) long-duration balloon experiment is designed to have world-leading sensitivity to ultrahigh-energy neutrinos at energies above 1 EeV. Probing this energy region is essential for understanding the extreme-energy universe at all distance scales. PUEO leverages experience from and supersedes the successful Antarctic Impulsive Transient Antenna (ANITA) program, with an improved design that drastically improves sensitivity by more than an order of magnitude at energies below 30 EeV. PUEO will either make the first significant detection of or set the best limits on ultrahigh-energy neutrino fluxes.

astro-ph.IM↗

arXiv2021

Search for multi-flare neutrino emissions in 10 years of IceCube data from a catalog of sources

A recent time-integrated analysis of a catalog of 110 candidate neutrino sources revealed a cumulative neutrino excess in the data collected by IceCube between April 6, 2008 and July 10, 2018. This excess, inconsistent with the background hypothesis in the Northern hemisphere at the $3.3~σ$ level, is associated with four sources: NGC 1068, TXS 0506+056, PKS 1424+240 and GB6 J1542+6129. This letter presents two time-dependent neutrino emission searches on the same data sample and catalog: a point-source search that looks for the most significant time-dependent source of the catalog by combining space, energy and time information of the events, and a population test based on binomial statistics that looks for a cumulative time-dependent neutrino excess from a subset of sources. Compared to previous time-dependent searches, these analyses enable a feature to possibly find multiple flares from a single direction with an unbinned maximum-likelihood method. M87 is found to be the most significant time-dependent source of this catalog at the level of $1.7~σ$ post-trial, and TXS 0506+056 is the only source for which two flares are reconstructed. The binomial test reports a cumulative time-dependent neutrino excess in the Northern hemisphere at the level of $3.0~σ$ associated with four sources: M87, TXS 0506+056, GB6 J1542+6129 and NGC 1068.

astro-ph.HE↗

arXiv2021

A Convolutional Neural Network based Cascade Reconstruction for the IceCube Neutrino Observatory

Continued improvements on existing reconstruction methods are vital to the success of high-energy physics experiments, such as the IceCube Neutrino Observatory. In IceCube, further challenges arise as the detector is situated at the geographic South Pole where computational resources are limited. However, to perform real-time analyses and to issue alerts to telescopes around the world, powerful and fast reconstruction methods are desired. Deep neural networks can be extremely powerful, and their usage is computationally inexpensive once the networks are trained. These characteristics make a deep learning-based approach an excellent candidate for the application in IceCube. A reconstruction method based on convolutional architectures and hexagonally shaped kernels is presented. The presented method is robust towards systematic uncertainties in the simulation and has been tested on experimental data. In comparison to standard reconstruction methods in IceCube, it can improve upon the reconstruction accuracy, while reducing the time necessary to run the reconstruction by two to three orders of magnitude.

hep-ex↗

arXiv2021

The IceCube Collaboration -- Contributions to the 37th International Cosmic Ray Conference (ICRC2021)

This list of contributions to the 37th International Cosmic Ray Conference in Berlin, Germany (12-23 July 2021) summarizes the latest results from the IceCube Neutrino Observatory. IceCube, completed 10 years ago at the geographic South Pole, comprises a surface detector designed to observe cosmic ray air showers, a cubic-kilometer array of optical sensors deployed deep in the ice sheet to observe TeV-PeV neutrinos, and a 15 Megaton deep-ice subdetector sensitive to >10 GeV neutrinos. Data from IceCube are used to investigate a broad set of key questions in physics and astrophysics, such as the origins of galactic and extragalactic cosmic rays, the fundamental properties of neutrinos, and searches for physics beyond the Standard Model. The papers in this index are grouped topically to highlight IceCube contributions related to neutrino and multi-messenger astrophysics, cosmic-ray physics, fundamental physics, education and public outreach, and research and development for next-generation neutrino observatories. Contributions related to IceCube-Gen2, the future extension of IceCube, are available in a separate collection.

astro-ph.HE↗

arXiv2021

The IceCube-Gen2 Collaboration -- Contributions to the 37th International Cosmic Ray Conference (ICRC2021)

IceCube-Gen2 is a planned extension of the IceCube Neutrino Observatory at the South Pole. The extension is optimized to search for sources of astrophysical neutrinos from TeV to EeV, and will improve the sensitivity of the observatory to neutrino point sources by a factor of five. The science case of IceCube-Gen2 is built on a successful decade of observations with IceCube. This index of contributions to the 37th International Cosmic Ray Conference in Berlin, Germany (12-23 July 2021) describes research and development efforts for IceCube-Gen2. Included are performance studies of next-generation optical sensors that will detect Cherenkov radiation from TeV-PeV cosmic rays and neutrinos; optimizations of the geometries of the surface and in-ice optical arrays; and estimates of the sensitivity of the proposed IceCube-Gen2 radio array to Askaryan emission from PeV-EeV neutrinos. Contributions related to the existing instrument, IceCube, are available in a separate collection.

astro-ph.HE↗

arXiv2021

Probing neutrino emission at GeV energies from compact binary mergers with the IceCube Neutrino Observatory

The advent of multi-messenger astronomy has allowed for new types of source searches by neutrino detectors. We present the results of the search for 0.5-100 GeV astrophysical neutrinos detected with IceCube and emitted from compact binary mergers detected by the LIGO, Virgo, and KAGRA interferometers from their first run of observation (O1) to the end of the first part of the fourth (O4a). An innovative approach is used to lower the energy threshold to 0.5 GeV and to search for an excess of GeV neutrinos in time coincidence with astrophysical transient events. Furthermore, we use a statistical combination of all observations, a binomial test, to search for a subpopulation of neutrino emitters. No significant excess was found from the studied mergers, with a best post-trial $p$-value of $40\%$, and there is currently no hint of a population of GeV neutrino emitters found in the IceCube data (post-trial $p$-value = $81\%$).

astro-ph.HE↗

arXiv2021

Search for GeV Neutrino Emission During Intense Gamma-Ray Solar Flares with the IceCube Neutrino Observatory

Solar flares convert magnetic energy into thermal and non-thermal plasma energy, the latter implying particle acceleration of charged particles such as protons. Protons are injected out of the coronal acceleration region and can interact with dense plasma in the lower solar atmosphere, producing mesons that subsequently decay into gamma rays and neutrinos at O(MeV-GeV) energies. We present the results of the first search for GeV neutrinos emitted during solar flares carried out with the IceCube Neutrino Observatory. While the experiment was originally designed to detect neutrinos with energies between 10 GeV and a few PeV, a new approach allowing for a O(GeV) energy threshold will be presented. The resulting limits allow us to constrain some of the theoretical estimates of the expected neutrino flux.

astro-ph.HE↗

arXiv2021

LeptonInjector and LeptonWeighter: A neutrino event generator and weighter for neutrino observatories

We present a high-energy neutrino event generator, called LeptonInjector, alongside an event weighter, called LeptonWeighter. Both are designed for large-volume Cherenkov neutrino telescopes such as IceCube. The neutrino event generator allows for quick and flexible simulation of neutrino events within and around the detector volume, and implements the leading Standard Model neutrino interaction processes relevant for neutrino observatories: neutrino-nucleon deep-inelastic scattering and neutrino-electron annihilation. In this paper, we discuss the event generation algorithm, the weighting algorithm, and the main functions of the publicly available code, with examples.

physics.comp-ph↗

arXiv2021

A muon-track reconstruction exploiting stochastic losses for large-scale Cherenkov detectors

IceCube is a cubic-kilometer Cherenkov telescope operating at the South Pole. The main goal of IceCube is the detection of astrophysical neutrinos and the identification of their sources. High-energy muon neutrinos are observed via the secondary muons produced in charge current interactions with nuclei in the ice. Currently, the best performing muon track directional reconstruction is based on a maximum likelihood method using the arrival time distribution of Cherenkov photons registered by the experiment's photomultipliers. A known systematic shortcoming of the prevailing method is to assume a continuous energy loss along the muon track. However at energies $>1$ TeV the light yield from muons is dominated by stochastic showers. This paper discusses a generalized ansatz where the expected arrival time distribution is parametrized by a stochastic muon energy loss pattern. This more realistic parametrization of the loss profile leads to an improvement of the muon angular resolution of up to $20\%$ for through-going tracks and up to a factor 2 for starting tracks over existing algorithms. Additionally, the procedure to estimate the directional reconstruction uncertainty has been improved to be more robust against numerical errors.

hep-ex↗

arXiv2021

Follow-up of astrophysical transients in real time with the IceCube Neutrino Observatory

In multi-messenger astronomy, rapid investigation of interesting transients is imperative. As an observatory with a 4$π$ steradian field of view and $\sim$99\% uptime, the IceCube Neutrino Observatory is a unique facility to follow up transients, and to provide valuable insight for other observatories and inform their observing decisions. Since 2016, IceCube has been using low-latency data to rapidly respond to interesting astrophysical events reported by the multi-messenger observational community. Here, we describe the pipeline used to perform these follow up analyses and provide a summary of the 58 analyses performed as of July 2020. We find no significant signal in the first 58 analyses performed. The pipeline has helped inform various electromagnetic observing strategies, and has constrained neutrino emission from potential hadronic cosmic accelerators.

astro-ph.HE↗

arXiv2021

A search for ultrahigh-energy neutrinos associated with astrophysical sources using the third flight of ANITA

The ANtarctic Impulsive Transient Antenna (ANITA) long-duration balloon experiment is sensitive to interactions of ultra high-energy (E > 10^{18} eV) neutrinos in the Antarctic ice sheet. The third flight of ANITA, lasting 22 days, began in December 2014. We develop a methodology to search for energetic neutrinos spatially and temporally coincident with potential source classes in ANITA data. This methodology is applied to several source classes: the TXS 0506+056 blazar and NGC 1068, the first potential TeV neutrino sources identified by IceCube, flaring high-energy blazars reported by the Fermi All-Sky Variability Analysis, gamma-ray bursts, and supernovae. Among searches within the five source classes, one candidate was identified as associated with SN 2015D, although not at a statistically significant level. We proceed to place upper limits on the source classes. We further comment on potential applications of this methodology to more sensitive future instruments.

astro-ph.HE↗

arXiv2021

Searches for neutrinos from cosmic-ray interactions in the Sun using seven years of IceCube data

Cosmic-ray interactions with the solar atmosphere are expected to produce particle showers which in turn produce neutrinos from weak decays of mesons. These solar atmospheric neutrinos (SA$ν$s) have never been observed experimentally. A detection would be an important step in understanding cosmic-ray propagation in the inner solar system and the dynamics of solar magnetic fields. SA$ν$s also represent an irreducible background to solar dark matter searches and a detection would allow precise characterization of this background. Here, we present the first experimental search based on seven years of data collected from May 2010 to May 2017 in the austral winter with the IceCube Neutrino Observatory. An unbinned likelihood analysis is performed for events reconstructed within 5 degrees of the center of the Sun. No evidence for a SA$ν$ flux is observed. After inclusion of systematic uncertainties, we set a 90\% upper limit of $1.02^{+0.20}_{-0.18}\cdot10^{-13}$~$\mathrm{GeV^{-1}cm^{-2}s^{-1}}$ at 1 TeV.

astro-ph.HE↗

arXiv2021

IceCube Data for Neutrino Point-Source Searches Years 2008-2018

IceCube has performed several all-sky searches for point-like neutrino sources using track-like events, including a recent time-integrated analysis using 10 years of IceCube data. This paper accompanies the public data release of these neutrino candidates detected by IceCube between April 6, 2008 and July 8, 2018. The selection includes through-going tracks, primarily due to muon neutrino candidates, that reach the detector from all directions, as well as neutrino track events that start within the instrumented volume. An updated selection and reconstruction for data taken after April 2012 slightly improves the sensitivity of the sample. While more than 80% of the sample overlaps between the old and new versions, differing events can lead to changes relative to the previous 7 year event selection. An a posteriori estimate of the significance of the 2014-2015 TXS flare is reported with an explanation of observed discrepancies with previous results. This public data release, which includes 10 years of data and binned detector response functions for muon neutrino signal events, shows improved sensitivity in generic time-integrated point source analyses and should be preferred over previous releases.

astro-ph.HE↗

arXiv2021

Long-baseline horizontal radio-frequency transmission through polar ice

We report on analysis of englacial radio-frequency (RF) pulser data received over horizontal baselines of 1--5 km, based on broadcasts from two sets of transmitters deployed to depths of up to 1500 meters at the South Pole. First, we analyze data collected usingtwo RF bicone transmitters 1400 meters below the ice surface, and frozen into boreholes drilled for the IceCube experiment in 2011. Additionally, in Dec., 2018, a fat-dipole antenna, fed by one of three high-voltage (~1 kV), fast (~(1-5 ns)) signal generators was lowered into the 1700-m deep icehole drilled for the South Pole Ice Core Experiment (SPICE), approximately 3 km from the geographic South Pole. Signals from transmitters were recorded on the five englacial multi-receiver ARA stations, with receiver depths between 60--200 m. We confirm the long, >1 km RF electric field attenuation length, test our observed signal arrival timing distributions against models, and measure birefringent asymmetries at the 0.15% level.

astro-ph.IM↗

arXiv2020

A search for time-dependent astrophysical neutrino emission with IceCube data from 2012 to 2017

High-energy neutrinos are unique messengers of the high-energy universe, tracing the processes of cosmic-ray acceleration. This paper presents analyses focusing on time-dependent neutrino point-source searches. A scan of the whole sky, making no prior assumption about source candidates, is performed, looking for a space and time clustering of high-energy neutrinos in data collected by the IceCube Neutrino Observatory between 2012 and 2017. No statistically significant evidence for a time-dependent neutrino signal is found with this search during this period since all results are consistent with the background expectation. Within this study period, the blazar 3C 279, showed strong variability, inducing a very prominent gamma-ray flare observed in 2015 June. This event motivated a dedicated study of the blazar, which consists of searching for a time-dependent neutrino signal correlated with the gamma-ray emission. No evidence for a time-dependent signal is found. Hence, an upper limit on the neutrino fluence is derived, allowing us to constrain a hadronic emission model.

astro-ph.HE↗

arXiv2020

Measurement of the high-energy all-flavor neutrino-nucleon cross section with IceCube

The flux of high-energy neutrinos passing through the Earth is attenuated due to their interactions with matter. The interaction rate is modulated by the neutrino interaction cross section and affects the flux arriving at the IceCube Neutrino Observatory, a cubic-kilometer neutrino detector embedded in the Antarctic ice sheet. We present a measurement of the neutrino cross section between 60 TeV and 10 PeV using the high-energy starting events (HESE) sample from IceCube with 7.5 years of data. The result is binned in neutrino energy and obtained using both Bayesian and frequentist statistics. We find it compatible with predictions from the Standard Model. Flavor information is explicitly included through updated morphology classifiers, proxies for the the three neutrino flavors. This is the first such measurement to use the three morphologies as observables and the first to account for neutrinos from tau decay.

hep-ex↗