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Просмотр Научные публикации / Препринты по Автор "Abbasi, R."
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- ПубликацияТолько метаданныеA calibration study of local ice and optical sensor properties in IceCube(2022) Abbasi, R.; Ackermann, M.; Adams, J.; Aguilar, J.; Besson, D.; Spiering, C.
- ПубликацияТолько метаданныеA convolutional neural network based cascade reconstruction for the IceCube Neutrino Observatory(2021) Abbasi, R.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Besson, D. Z.; Spiering, C.© 2021 IOP Publishing Ltd and Sissa MedialabContinued 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.
- ПубликацияТолько метаданныеA muon-track reconstruction exploiting stochastic losses for large-scale Cherenkov detectors(2021) Abbasi, R.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Besson, D. Z.© 2021 The Author(s).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.
- ПубликацияТолько метаданныеA New Search for Neutrino Point Sources with IceCube(2022) Abbasi, R.; Ackermann, M.; Adams, J.; Aguilar, J.; Besson, D.; Spiering, C.
- ПубликацияТолько метаданныеA next-generation optical sensor for IceCube-Gen2(2022) Basu, V.; Ishihara, A.; Dittmer, M.; Shimizu, N.; Abbasi, R.; Besson, D.; Spiering, C.
- ПубликацияТолько метаданныеA novel microstructure-based model to explain the IceCube ice anisotropy(2022) Chirkin, D.; Rongen, M.; Abbasi, R.; Ackermann, M.; Besson, D.; Spiering, C.
- ПубликацияТолько метаданныеA Posterior Analysis on IceCube Double Pulse Tau Neutrino Candidates(2022) Tian, W.; Abbasi, R.; Ackermann, M.; Adams, J.; Besson, D.; Spiering, C.
- ПубликацияТолько метаданныеA Search for Neutrino Sources with Cascade Events in IceCube(2022) Sclafani, S.; Huennefeld, M.; Abbasi, R.; Ackermann, M.; Adams, J.; Besson, D.; Spiering, C.
- ПубликацияТолько метаданныеA Search for Neutrinos from Decaying Dark Matter in Galaxy Clusters and Galaxies with IceCube(2022) Jeong, M.; Abbasi, R.; Ackermann, M.; Besson, D.; Spiering, C.
- ПубликацияТолько метаданныеA Search for Time-dependent Astrophysical Neutrino Emission with IceCube Data from 2012 to 2017(2021) Abbasi, R.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Besson, D. Z.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, as 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.
- ПубликацияТолько метаданныеA time-independent search for neutrinos from galaxy clusters with IceCube(2022) Abbasi, R.; Ackermann, M.; Adams, J.; Aguilar, J.; Besson, D.; Spiering, C.
- ПубликацияТолько метаданныеA Time-Variability Test for Candidate Neutrino Sources Observed with IceCube(2022) Dave, P.; Abbasi, R.; Ackermann, M.; Adams, J.; Besson, D.; Spiering, C.
- ПубликацияТолько метаданныеAll-flavor constraints on nonstandard neutrino interactions and generalized matter potential with three years of IceCube DeepCore data(2021) Abbasi, R.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Besson, D. Z.; Spiering, C.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.
- ПубликацияТолько метаданныеAnalysis framework for Multi-messenger Astronomy with IceCube(2022) Abbasi, R.; Ackermann, M.; Adams, J.; Aguilar, J.; Besson, D.; Spiering, C.
- ПубликацияТолько метаданныеCamera Calibration for the IceCube Upgrade and Gen2(2022) Abbasi, R.; Ackermann, M.; Adams, J.; Besson, D.; Spiering, C.; Kang, W.
- ПубликацияТолько метаданныеCharacterization of the PeV astrophysical neutrino energy spectrum with IceCube using down-going tracks(2022) Abbasi, R.; Ackermann, M.; Adams, J.; Aguilar, J.; Besson, D.; Spiering, C.
- ПубликацияТолько метаданныеCombining Maximum-Likelihood with Deep Learning for Event Reconstruction in IceCube(2022) Hunnefeld, M.; Abbasi, R.; Ackermann, M.; Adams, J.; Besson, D.; Spiering, C.
- ПубликацияТолько метаданныеCompleting Aganta Kairos: Capturing Metaphysical Time on the Seventh Continent(2022) Madsen, J.; Mulot, L.; Abbasi, R.; Ackermann, M.; Besson, D.; Spiering, C.
- ПубликацияТолько метаданныеConcept Study of a Radio Array Embedded in a Deep Gen2-like Optical Array(2022) Bishop, A.; Hokanson-Fasig, B.; Karle, A.; Lu, L.; Abbasi, R.; Besson, D.; Spiering, C.
- ПубликацияТолько метаданныеCosmic ray spectrum from 250 TeV to 10 PeV using IceTop(2020) Aartsen, M. G.; Abbasi, R.; Ackermann, M.; Adams, J.; Besson, D. Z.We report here an extension of the measurement of the all-particle cosmic-ray spectrum with IceTop to lower energy. The new measurement gives full coverage of the knee region of the spectrum and reduces the gap in energy between previous IceTop and direct measurements. With a new trigger that selects events in closely spaced detectors in the center of the array, the IceTop energy threshold is lowered by almost an order of magnitude below its previous threshold of 2 PeV. In this paper we explain how the new trigger is implemented, and we describe the new machine-learning method developed to deal with events with very few detectors hit. We compare the results with previous measurements by IceTop and others that overlap at higher energy and with HAWC and Tibet in the 100 TeV range.