ORCID Profile
0000-0002-6305-3041
Current Organisation
TRIUMF
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Publisher: American Physical Society (APS)
Date: 16-06-2021
Publisher: American Physical Society (APS)
Date: 16-06-2020
Publisher: American Physical Society (APS)
Date: 15-02-2019
Publisher: American Physical Society (APS)
Date: 21-06-2021
Publisher: Springer Science and Business Media LLC
Date: 2020
DOI: 10.1140/EPJC/S10052-019-7555-0
Abstract: The Neutrino Mass Ordering (NMO) remains one of the outstanding questions in the field of neutrino physics. One strategy to measure the NMO is to observe matter effects in the oscillation pattern of atmospheric neutrinos above $$\\sim 1\\,\\mathrm {GeV}$$ ∼ 1 GeV , as proposed for several next-generation neutrino experiments. Moreover, the existing IceCube DeepCore detector can already explore this type of measurement. We present the development and application of two independent analyses to search for the signature of the NMO with three years of DeepCore data. These analyses include a full treatment of systematic uncertainties and a statistically-rigorous method to determine the significance for the NMO from a fit to the data. Both analyses show that the dataset is fully compatible with both mass orderings. For the more sensitive analysis, we observe a preference for normal ordering with a p -value of $$p_\\mathrm {IO} = 15.3\\%$$ p IO = 15.3 % and $$\\mathrm {CL}_\\mathrm {s}=53.3\\%$$ CL s = 53.3 % for the inverted ordering hypothesis, while the experimental results from both analyses are consistent within their uncertainties. Since the result is independent of the value of $$\\delta _\\mathrm {CP}$$ δ CP and obtained from energies $$E_\\nu \\gtrsim 5\\,\\mathrm {GeV}$$ E ν ≳ 5 GeV , it is complementary to recent results from long-baseline experiments. These analyses set the groundwork for the future of this measurement with more capable detectors, such as the IceCube Upgrade and the proposed PINGU detector.
Publisher: American Physical Society (APS)
Date: 21-02-2020
Publisher: American Association for the Advancement of Science (AAAS)
Date: 11-07-2018
Abstract: Previous detections of in idual astrophysical sources of neutrinos are limited to the Sun and the supernova 1987A, whereas the origins of the diffuse flux of high-energy cosmic neutrinos remain unidentified. On 22 September 2017, we detected a high-energy neutrino, IceCube-170922A, with an energy of ~290 tera-electron volts. Its arrival direction was consistent with the location of a known γ-ray blazar, TXS 0506+056, observed to be in a flaring state. An extensive multiwavelength c aign followed, ranging from radio frequencies to γ-rays. These observations characterize the variability and energetics of the blazar and include the detection of TXS 0506+056 in very-high-energy γ-rays. This observation of a neutrino in spatial coincidence with a γ-ray-emitting blazar during an active phase suggests that blazars may be a source of high-energy neutrinos.
Publisher: Springer Science and Business Media LLC
Date: 10-2020
Abstract: The electron (anti-)neutrino component of the T2K neutrino beam constitutes the largest background in the measurement of electron (anti-)neutrino appearance at the far detector. The electron neutrino scattering is measured directly with the T2K off-axis near detector, ND280. The selection of the electron (anti-)neutrino events in the plastic scintillator target from both neutrino and anti-neutrino mode beams is discussed in this paper. The flux integrated single differential charged-current inclusive electron (anti-)neutrino cross-sections, dσ/dp and dσ/d cos( θ ), and the total cross-sections in a limited phase-space in momentum and scattering angle ( p 300 MeV/c and θ ≤ 45°) are measured using a binned maximum likelihood fit and compared to the neutrino Monte Carlo generator predictions, resulting in good agreement.
Publisher: American Astronomical Society
Date: 27-03-2020
Publisher: American Physical Society (APS)
Date: 02-06-2020
Publisher: arXiv
Date: 2017
Publisher: American Astronomical Society
Date: 13-11-2019
Publisher: IOP Publishing
Date: 21-10-2019
Publisher: American Astronomical Society
Date: 27-02-2020
Publisher: American Physical Society (APS)
Date: 23-10-2019
Publisher: American Physical Society (APS)
Date: 27-10-2020
Publisher: American Physical Society (APS)
Date: 17-09-2023
Publisher: IOP Publishing
Date: 12-02-2021
Publisher: IOP Publishing
Date: 16-07-2020
Publisher: American Astronomical Society
Date: 06-07-2020
Publisher: Elsevier BV
Date: 03-2020
Publisher: American Astronomical Society
Date: 08-2022
Abstract: For several decades, the origin of ultra-high-energy cosmic rays (UHECRs) has been an unsolved question of high-energy astrophysics. One approach for solving this puzzle is to correlate UHECRs with high-energy neutrinos, since neutrinos are a direct probe of hadronic interactions of cosmic rays and are not deflected by magnetic fields. In this paper, we present three different approaches for correlating the arrival directions of neutrinos with the arrival directions of UHECRs. The neutrino data are provided by the IceCube Neutrino Observatory and ANTARES, while the UHECR data with energies above ∼50 EeV are provided by the Pierre Auger Observatory and the Telescope Array. All experiments provide increased statistics and improved reconstructions with respect to our previous results reported in 2015. The first analysis uses a high-statistics neutrino s le optimized for point-source searches to search for excesses of neutrino clustering in the vicinity of UHECR directions. The second analysis searches for an excess of UHECRs in the direction of the highest-energy neutrinos. The third analysis searches for an excess of pairs of UHECRs and highest-energy neutrinos on different angular scales. None of the analyses have found a significant excess, and previously reported overfluctuations are reduced in significance. Based on these results, we further constrain the neutrino flux spatially correlated with UHECRs.
Publisher: American Physical Society (APS)
Date: 08-02-2020
Publisher: Oxford University Press (OUP)
Date: 02-03-2021
DOI: 10.1093/PTEP/PTAB014
Abstract: We report measurements of the flux-integrated ν̅μ and ν̅μ + νμ charged-current cross-sections on water and hydrocarbon targets using the T2K anti-neutrino beam with a mean beam energy of 0.86 GeV. The signal is defined as the (anti-)neutrino charged-current interaction with one induced $\\mu^\\pm$ and no detected charged pion or proton. These measurements are performed using a new WAGASCI module recently added to the T2K setup in combination with the INGRID Proton Module. The phase space of muons is restricted to the high-detection efficiency region, $p_{\\mu}& ~{\\rm MeV}/c$ and $\\theta_{\\mu}& ^{\\circ}$, in the laboratory frame. An absence of pions and protons in the detectable phase spaces of $p_{\\pi}& ~{\\rm MeV}/c$, $\\theta_{\\pi}& ^{\\circ}$ and $p_{\\rm p}& ~{\\rm MeV}/c$, $\\theta_{\\rm p}& ^{\\circ}$ is required. In this paper, both the $\\overline{\\nu}_\\mu$ cross-sections and $\\overline{\\nu}_\\mu+\\nu_\\mu$ cross-sections on water and hydrocarbon targets and their ratios are provided by using the D’Agostini unfolding method. The results of the integrated $\\overline{\\nu}_\\mu$ cross-section measurements over this phase space are $\\sigma_{\\rm H_{2}O}=(1.082\\pm0.068(\\rm stat.)^{+0.145}_{-0.128}(\\rm syst.)) \\times 10^{-39}\\,{\\rm cm^{2} / nucleon}$, $\\sigma_{\\rm CH}=(1.096\\pm0.054(\\rm stat.)^{+0.132}_{-0.117}(\\rm syst.)) \\times 10^{-39}\\,{\\rm cm^{2} / nucleon}$, and $\\sigma_{\\rm H_{2}O}/\\sigma_{\\rm CH} = 0.987\\pm0.078(\\rm stat.)^{+0.093}_{-0.090}(\\rm syst.)$. The $\\overline{\\nu}_\\mu+\\nu_\\mu$ cross-section is $\\sigma_{\\rm H_{2}O} = (1.155\\pm0.064(\\rm stat.)^{+0.148}_{-0.129}(\\rm syst.)) \\times 10^{-39}\\,{\\rm cm^{2} / nucleon}$, $\\sigma_{\\rm CH}=(1.159\\pm0.049(\\rm stat.)^{+0.129}_{-0.115}(\\rm syst.)) \\times 10^{-39}\\,{\\rm cm^{2} / nucleon}$, and $\\sigma_{\\rm H_{2}O}/\\sigma_{\\rm CH}=0.996\\pm0.069(\\rm stat.)^{+0.083}_{-0.078}(\\rm syst.)$.
Publisher: Springer Science and Business Media LLC
Date: 09-2020
DOI: 10.1140/EPJC/S10052-020-8069-5
Abstract: Adopting the Standard Halo Model (SHM) of an isotropic Maxwellian velocity distribution for dark matter (DM) particles in the Galaxy, the most stringent current constraints on their spin-dependent scattering cross-section with nucleons come from the IceCube neutrino observatory and the PICO-60 $$\\hbox {C}_3\\hbox {F}_8$$ C 3 F 8 superheated bubble chamber experiments. The former is sensitive to high energy neutrinos from the self-annihilation of DM particles captured in the Sun, while the latter looks for nuclear recoil events from DM scattering off nucleons. Although slower DM particles are more likely to be captured by the Sun, the faster ones are more likely to be detected by PICO. Recent N-body simulations suggest significant deviations from the SHM for the smooth halo component of the DM, while observations hint at a dominant fraction of the local DM being in substructures. We use the method of Ferrer et al. (JCAP 1509: 052, 2015) to exploit the complementarity between the two approaches and derive conservative constraints on DM-nucleon scattering. Our results constrain $$\\sigma _{\\mathrm{SD}} \\lesssim 3 \\times 10^{-39} \\mathrm {cm}^2$$ σ SD ≲ 3 × 10 - 39 cm 2 ( $$6 \\times 10^{-38} \\mathrm {cm}^2$$ 6 × 10 - 38 cm 2 ) at $$\\gtrsim 90\\%$$ ≳ 90 % C.L. for a DM particle of mass 1 TeV annihilating into $$\\tau ^+ \\tau ^-$$ τ + τ - ( $$b\\bar{b}$$ b b ¯ ) with a local density of $$\\rho _{\\mathrm{DM}} = 0.3~\\mathrm {GeV/cm}^3$$ ρ DM = 0.3 GeV / cm 3 . The constraints scale inversely with $$\\rho _{\\mathrm{DM}}$$ ρ DM and are independent of the DM velocity distribution.
Publisher: IOP Publishing
Date: 04-02-2020
Publisher: American Astronomical Society
Date: 18-02-2020
Publisher: American Astronomical Society
Date: 10-2022
Abstract: Galaxy clusters have the potential to accelerate cosmic rays (CRs) to ultrahigh energies via accretion shocks or embedded CR acceleration sites. The CRs with energies below the Hillas condition will be confined within the cluster and eventually interact with the intracluster medium gas to produce secondary neutrinos and gamma rays. Using 9.5 yr of muon neutrino track events from the IceCube Neutrino Observatory, we report the results of a stacking analysis of 1094 galaxy clusters with masses ≳10 14 M ⊙ and redshifts between 0.01 and ∼1 detected by the Planck mission via the Sunyaev–Zel’dovich effect. We find no evidence for significant neutrino emission and report upper limits on the cumulative unresolved neutrino flux from massive galaxy clusters after accounting for the completeness of the catalog up to a redshift of 2, assuming three different weighting scenarios for the stacking and three different power-law spectra. Weighting the sources according to mass and distance, we set upper limits at a 90% confidence level that constrain the flux of neutrinos from massive galaxy clusters (≳10 14 M ⊙ ) to be no more than 4.6% of the diffuse IceCube observations at 100 TeV, assuming an unbroken E −2.5 power-law spectrum.
Publisher: EDP Sciences
Date: 06-2019
DOI: 10.1051/0004-6361/201935171
Abstract: In order to identify the sources of the observed diffuse high-energy neutrino flux, it is crucial to discover their electromagnetic counterparts. To increase the sensitivity of detecting counterparts of transient or variable sources by telescopes with a limited field of view, IceCube began releasing alerts for single high-energy ( E ν 60 TeV) neutrino detections with sky localisation regions of order 1° radius in 2016. We used Pan-STARRS1 to follow-up five of these alerts during 2016–2017 to search for any optical transients that may be related to the neutrinos. Typically 10–20 faint ( m i P1 ≲ 22.5 mag) extragalactic transients are found within the Pan-STARRS1 footprints and are generally consistent with being unrelated field supernovae (SNe) and AGN. We looked for unusual properties of the detected transients, such as temporal coincidence of explosion epoch with the IceCube timest , or other peculiar light curve and physical properties. We found only one transient that had properties worthy of a specific follow-up. In the Pan-STARRS1 imaging for IceCube-160427A (probability to be of astrophysical origin of ∼50%), we found a SN PS16cgx, located at 10.0′ from the nominal IceCube direction. Spectroscopic observations of PS16cgx showed that it was an H-poor SN at redshift z = 0.2895 ± 0.0001. The spectra and light curve resemble some high-energy Type Ic SNe, raising the possibility of a jet driven SN with an explosion epoch temporally coincident with the neutrino detection. However, distinguishing Type Ia and Type Ic SNe at this redshift is notoriously difficult. Based on all available data we conclude that the transient is more likely to be a Type Ia with relatively weak Si II absorption and a fairly normal rest-frame r -band light curve. If, as predicted, there is no high-energy neutrino emission from Type Ia SNe, then PS16cgx must be a random coincidence, and unrelated to the IceCube-160427A. We find no other plausible optical transient for any of the five IceCube events observed down to a 5 σ limiting magnitude of m i P1 ≈ 22 mag, between 1 day and 25 days after detection.
Publisher: American Astronomical Society
Date: 03-2022
Abstract: We present a measurement of the high-energy astrophysical muon–neutrino flux with the IceCube Neutrino Observatory. The measurement uses a high-purity selection of 650k neutrino-induced muon tracks from the northern celestial hemisphere, corresponding to 9.5 yr of experimental data. With respect to previous publications, the measurement is improved by the increased size of the event s le and the extended model testing beyond simple power-law hypotheses. An updated treatment of systematic uncertainties and atmospheric background fluxes has been implemented based on recent models. The best-fit single power-law parameterization for the astrophysical energy spectrum results in a normalization of ϕ @ 100 TeV ν μ + ν ¯ μ = 1.44 − 0.26 + 0.25 × 10 − 18 GeV − 1 cm − 2 s − 1 sr − 1 and a spectral index γ SPL = 2.37 − 0.09 + 0.09 , constrained in the energy range from 15 TeV to 5 PeV. The model tests include a single power law with a spectral cutoff at high energies, a log-parabola model, several source-class-specific flux predictions from the literature, and a model-independent spectral unfolding. The data are consistent with a single power-law hypothesis, however, spectra with softening above one PeV are statistically more favorable at a two-sigma level.
Publisher: American Physical Society (APS)
Date: 26-01-2021
Publisher: American Astronomical Society
Date: 10-2022
Abstract: The majority of astrophysical neutrinos have undetermined origins. The IceCube Neutrino Observatory has observed astrophysical neutrinos but has not yet identified their sources. Blazars are promising source candidates, but previous searches for neutrino emission from populations of blazars detected in ≳GeV gamma rays have not observed any significant neutrino excess. Recent findings in multimessenger astronomy indicate that high-energy photons, coproduced with high-energy neutrinos, are likely to be absorbed and reemitted at lower energies. Thus, lower-energy photons may be better indicators of TeV–PeV neutrino production. This paper presents the first time-integrated stacking search for astrophysical neutrino emission from MeV-detected blazars in the first Fermi Large Area Telescope low energy (1FLE) catalog using ten years of IceCube muon–neutrino data. The results of this analysis are found to be consistent with a background-only hypothesis. Assuming an E −2 neutrino spectrum and proportionality between the blazars MeV gamma-ray fluxes and TeV–PeV neutrino flux, the upper limit on the 1FLE blazar energy-scaled neutrino flux is determined to be 1.64 × 10 −12 TeV cm −2 s −1 at 90% confidence level. This upper limit is approximately 1% of IceCube’s diffuse muon–neutrino flux measurement.
Publisher: American Astronomical Society
Date: 11-2022
Abstract: Gamma-ray bursts (GRBs) are considered as promising sources of ultra-high-energy cosmic rays (UHECRs) due to their large power output. Observing a neutrino flux from GRBs would offer evidence that GRBs are hadronic accelerators of UHECRs. Previous IceCube analyses, which primarily focused on neutrinos arriving in temporal coincidence with the prompt gamma-rays, found no significant neutrino excess. The four analyses presented in this paper extend the region of interest to 14 days before and after the prompt phase, including generic extended time windows and targeted precursor searches. GRBs were selected between 2011 May and 2018 October to align with the data set of candidate muon-neutrino events observed by IceCube. No evidence of correlation between neutrino events and GRBs was found in these analyses. Limits are set to constrain the contribution of the cosmic GRB population to the diffuse astrophysical neutrino flux observed by IceCube. Prompt neutrino emission from GRBs is limited to ≲1% of the observed diffuse neutrino flux, and emission on timescales up to 10 4 s is constrained to 24% of the total diffuse flux.
Publisher: American Astronomical Society
Date: 04-2020
Publisher: American Astronomical Society
Date: 20-04-2020
Publisher: American Astronomical Society
Date: 05-2022
Abstract: We present the first comprehensive search for high-energy neutrino emission from high- and low-mass X-ray binaries conducted by IceCube. Galactic X-ray binaries are long-standing candidates for the source of Galactic hadronic cosmic rays and neutrinos. The compact object in these systems can be the site of cosmic-ray acceleration, and neutrinos can be produced by interactions of cosmic rays with radiation or gas, in the jet of a microquasar, in the stellar wind, or in the atmosphere of the companion star. We study X-ray binaries using 7.5 yr of IceCube data with three separate analyses. In the first, we search for periodic neutrino emission from 55 binaries in the Northern Sky with known orbital periods. In the second, the X-ray light curves of 102 binaries across the entire sky are used as templates to search for time-dependent neutrino emission. Finally, we search for time-integrated emission of neutrinos for a list of 4 notable binaries identified as microquasars. In the absence of a significant excess, we place upper limits on the neutrino flux for each hypothesis and compare our results with theoretical predictions for several binaries. In addition, we evaluate the sensitivity of the next generation neutrino telescope at the South Pole, IceCube-Gen2, and demonstrate its power to identify potential neutrino emission from these binary sources in the Galaxy.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Stephanie Bron.