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Start Over Author "Bagherpour, H." Journal physical review letters
5 results on '"Bagherpour, H."'

1. eV-Scale Sterile Neutrino Search Using Eight Years of Atmospheric Muon Neutrino Data from the IceCube Neutrino Observatory

Author

Aartsen, MG, Abbasi, R, Ackermann, M, Adams, J, Aguilar, JA, Ahlers, M, Ahrens, M, Alispach, C, Amin, NM, Andeen, K, Anderson, T, Ansseau, I, Anton, G, Argüelles, C, Auffenberg, J, Axani, S, Bagherpour, H, Bai, X, Balagopal, A, Barbano, A, Barwick, SW, Bastian, B, Basu, V, Baum, V, Baur, S, Bay, R, Beatty, JJ, Becker, K-H, Tjus, J Becker, BenZvi, S, Berley, D, Bernardini, E, Besson, DZ, Binder, G, Bindig, D, Blaufuss, E, Blot, S, Bohm, C, Böser, S, Botner, O, Böttcher, J, Bourbeau, E, Bourbeau, J, Bradascio, F, Braun, J, Bron, S, Brostean-Kaiser, J, Burgman, A, Buscher, J, Busse, RS, Carver, T, Chen, C, Cheung, E, Chirkin, D, Choi, S, Clark, BA, Clark, K, Classen, L, Coleman, A, Collin, GH, Conrad, JM, Coppin, P, Correa, P, Cowen, DF, Cross, R, Dave, P, De Clercq, C, DeLaunay, JJ, Dembinski, H, Deoskar, K, De Ridder, S, Desai, A, Desiati, P, de Vries, KD, de Wasseige, G, de With, M, DeYoung, T, Dharani, S, Diaz, A, Díaz-Vélez, JC, Dujmovic, H, Dunkman, M, DuVernois, MA, Dvorak, E, Ehrhardt, T, Eller, P, Engel, R, Evenson, PA, Fahey, S, Fazely, AR, Fedynitch, A, Felde, J, Fienberg, AT, Filimonov, K, Finley, C, Fox, D, Franckowiak, A, Friedman, E, Fritz, A, and Gaisser, TK

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, IceCube Collaboration, hep-ex, hep-ph, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract

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

Published
2020

2. Characteristics of the Diffuse Astrophysical Electron and Tau Neutrino Flux with Six Years of IceCube High Energy Cascade Data

Author

Aartsen, MG, Ackermann, M, Adams, J, Aguilar, JA, Ahlers, M, Ahrens, M, Alispach, C, Andeen, K, Anderson, T, Ansseau, I, Anton, G, Argüelles, C, Auffenberg, J, Axani, S, Backes, P, Bagherpour, H, Bai, X, V., A Balagopal, Barbano, A, Barwick, SW, Bastian, B, Baum, V, Baur, S, Bay, R, Beatty, JJ, Becker, K-H, Tjus, J Becker, BenZvi, S, Berley, D, Bernardini, E, Besson, DZ, Binder, G, Bindig, D, Blaufuss, E, Blot, S, Bohm, C, Böser, S, Botner, O, Böttcher, J, Bourbeau, E, Bourbeau, J, Bradascio, F, Braun, J, Bron, S, Brostean-Kaiser, J, Burgman, A, Buscher, J, Busse, RS, Carver, T, Chen, C, Cheung, E, Chirkin, D, Choi, S, Clark, K, Classen, L, Coleman, A, Collin, GH, Conrad, JM, Coppin, P, Correa, P, Cowen, DF, Cross, R, Dave, P, De Clercq, C, DeLaunay, JJ, Dembinski, H, Deoskar, K, De Ridder, S, Desiati, P, de Vries, KD, de Wasseige, G, de With, M, DeYoung, T, Diaz, A, Díaz-Vélez, JC, Dujmovic, H, Dunkman, M, Dvorak, E, Eberhardt, B, Ehrhardt, T, Eller, P, Engel, R, Evenson, PA, Fahey, S, Fazely, AR, Felde, J, Filimonov, K, Finley, C, Fox, D, Franckowiak, A, Friedman, E, Fritz, A, Gaisser, TK, Gallagher, J, Ganster, E, Garrappa, S, Gerhardt, L, Ghorbani, K, Glauch, T, and Glüsenkamp, T

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, IceCube Collaboration, astro-ph.HE, astro-ph.CO, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract

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 2.6 PeV, is consistent with a single power-law model as expected from Fermi-type acceleration of high energy particles at astrophysical sources. We find the flux spectral index to be γ=2.53±0.07 and a flux normalization for each neutrino flavor of ϕ_{astro}=1.66_{-0.27}^{+0.25} at E_{0}=100  TeV, in agreement with IceCube's complementary muon neutrino results and with all-neutrino flavor fit results. In the measured energy range we reject spectral indices γ≤2.28 at ≥3σ significance level. Because of high neutrino energy resolution and low atmospheric neutrino backgrounds, this analysis provides the most detailed characterization of the neutrino flux at energies below ∼100  TeV compared to previous IceCube results. Results from fits assuming more complex neutrino flux models suggest a flux softening at high energies and a flux hardening at low energies (p value ≥0.06). The sizable and smooth flux measured below ∼100  TeV remains a puzzle. In order to not violate the isotropic diffuse gamma-ray background as measured by the Fermi Large Area Telescope, it suggests the existence of astrophysical neutrino sources characterized by dense environments which are opaque to gamma rays.

Published
2020

3. Time-Integrated Neutrino Source Searches with 10 Years of IceCube Data

Author

Aartsen, MG, Ackermann, M, Adams, J, Aguilar, JA, Ahlers, M, Ahrens, M, Alispach, C, Andeen, K, Anderson, T, Ansseau, I, Anton, G, Argüelles, C, Auffenberg, J, Axani, S, Backes, P, Bagherpour, H, Bai, X, Balagopal, A, Barbano, A, Barwick, SW, Bastian, B, Baum, V, Baur, S, Bay, R, Beatty, JJ, Becker, K-H, Tjus, J Becker, BenZvi, S, Berley, D, Bernardini, E, Besson, DZ, Binder, G, Bindig, D, Blaufuss, E, Blot, S, Bohm, C, Börner, M, Böser, S, Botner, O, Böttcher, J, Bourbeau, E, Bourbeau, J, Bradascio, F, Braun, J, Bron, S, Brostean-Kaiser, J, Burgman, A, Buscher, J, Busse, RS, Carver, T, Chen, C, Cheung, E, Chirkin, D, Choi, S, Clark, K, Classen, L, Coleman, A, Collin, GH, Conrad, JM, Coppin, P, Correa, P, Cowen, DF, Cross, R, Dave, P, De Clercq, C, DeLaunay, JJ, Dembinski, H, Deoskar, K, De Ridder, S, Desiati, P, de Vries, KD, de Wasseige, G, de With, M, DeYoung, T, Diaz, A, Díaz-Vélez, JC, Dujmovic, H, Dunkman, M, Dvorak, E, Eberhardt, B, Ehrhardt, T, Eller, P, Engel, R, Evenson, PA, Fahey, S, Fazely, AR, Felde, J, Filimonov, K, Finley, C, Fox, D, Franckowiak, A, Friedman, E, Fritz, A, Gaisser, TK, Gallagher, J, Ganster, E, Garrappa, S, Gerhardt, L, Ghorbani, K, and Glauch, T

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, astro-ph.HE, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract

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. The most significant point in the northern hemisphere from scanning the sky is coincident with the Seyfert II galaxy NGC 1068, which was included in the source catalog search. The excess at the coordinates of NGC 1068 is inconsistent with background expectations at the level of 2.9σ after accounting for statistical trials from the entire catalog. The combination of this result along with excesses observed at the coordinates of three other sources, including TXS 0506+056, suggests that, collectively, correlations with sources in the northern catalog are inconsistent with background at 3.3σ significance. The southern catalog is consistent with background. These results, all based on searches for a cumulative neutrino signal integrated over the 10 years of available data, motivate further study of these and similar sources, including time-dependent analyses, multimessenger correlations, and the possibility of stronger evidence with coming upgrades to the detector.

Published
2020

4. Constraints on Minute-Scale Transient Astrophysical Neutrino Sources

Author

Aartsen, MG, Ackermann, M, Adams, J, Aguilar, JA, Ahlers, M, Ahrens, M, Al Samarai, I, Altmann, D, Andeen, K, Anderson, T, Ansseau, I, Anton, G, Argüelles, C, Auffenberg, J, Axani, S, Backes, P, Bagherpour, H, Bai, X, Barbano, A, Barron, JP, Barwick, SW, Baum, V, Bay, R, Beatty, JJ, Tjus, J Becker, Becker, K-H, BenZvi, S, Berley, D, Bernardini, E, Besson, DZ, Binder, G, Bindig, D, Blaufuss, E, Blot, S, Bohm, C, Börner, M, Bos, F, Böser, S, Botner, O, Bourbeau, E, Bourbeau, J, Bradascio, F, Braun, J, Brenzke, M, Bretz, H-P, Bron, S, Brostean-Kaiser, J, Burgman, A, Busse, RS, Carver, T, Cheung, E, Chirkin, D, Christov, A, Clark, K, Classen, L, Collin, GH, Conrad, JM, Coppin, P, Correa, P, Cowen, DF, Cross, R, Dave, P, Day, M, de André, JPAM, De Clercq, C, DeLaunay, JJ, Dembinski, H, Deoskar, K, De Ridder, S, Desiati, P, de Vries, KD, de Wasseige, G, de With, M, DeYoung, T, Díaz-Vélez, JC, di Lorenzo, V, Dujmovic, H, Dumm, JP, Dunkman, M, Dvorak, E, Eberhardt, B, Ehrhardt, T, Eichmann, B, Eller, P, Evans, PA, Evenson, PA, Fahey, S, Fazely, AR, Felde, J, Filimonov, K, Finley, C, Franckowiak, A, Friedman, E, Fritz, A, Gaisser, TK, Gallagher, J, Ganster, E, Gerhardt, L, Ghorbani, K, and Giang, W

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Astronomical Sciences, Physical Sciences, astro-ph.HE, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract

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. Here, we calculate generic bounds on the neutrino flux of short-lived transient sources. Assuming an E^{-2.5} neutrino spectrum, we find that the neutrino flux of rare sources, like long gamma-ray bursts, is constrained to

Published
2019

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

Author

Aartsen, MG, Ackermann, M, Adams, J, Aguilar, JA, Ahlers, M, Ahrens, M, Al Samarai, I, Altmann, D, Andeen, K, Anderson, T, Ansseau, I, Anton, G, Argüelles, C, Auffenberg, J, Axani, S, Bagherpour, H, Bai, X, Barron, JP, Barwick, SW, Baum, V, Bay, R, Beatty, JJ, Tjus, J Becker, Becker, K-H, BenZvi, S, Berley, D, Bernardini, E, Besson, DZ, Binder, G, Bindig, D, Blaufuss, E, Blot, S, Bohm, C, Börner, M, Bos, F, Bose, D, Böser, S, Botner, O, Bourbeau, J, Bradascio, F, Braun, J, Brayeur, L, Brenzke, M, Bretz, H-P, Bron, S, Brostean-Kaiser, J, Burgman, A, Carver, T, Casey, J, Casier, M, Cheung, E, Chirkin, D, Christov, A, Clark, K, Classen, L, Coenders, S, Collin, GH, Conrad, JM, Cowen, DF, Cross, R, Day, M, de André, JPAM, De Clercq, C, DeLaunay, JJ, Dembinski, H, De Ridder, S, Desiati, P, de Vries, KD, de Wasseige, G, de With, M, DeYoung, T, Díaz-Vélez, JC, di Lorenzo, V, Dujmovic, H, Dumm, JP, Dunkman, M, Eberhardt, B, Ehrhardt, T, Eichmann, B, Eller, P, Evenson, PA, Fahey, S, Fazely, AR, Felde, J, Filimonov, K, Finley, C, Flis, S, Franckowiak, A, Friedman, E, Fuchs, T, Gaisser, TK, Gallagher, J, Gerhardt, L, Ghorbani, K, Giang, W, Glauch, T, Glüsenkamp, T, Goldschmidt, A, Gonzalez, JG, and Grant, D

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, IceCube Collaboration, hep-ex, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract

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. This analysis uses neutrinos from the full sky with reconstructed energies from 5.6 to 56 GeV. We measure Δm_{32}^{2}=2.31_{-0.13}^{+0.11}×10^{-3}  eV^{2} and sin^{2}θ_{23}=0.51_{-0.09}^{+0.07}, assuming normal neutrino mass ordering. These results are consistent with, and of similar precision to, those from accelerator- and reactor-based experiments.

Published
2018

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