| 1. |
- Aartsen, M. G., et al.
(författare)
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Neutrino interferometry for high-precision tests of Lorentz symmetry with IceCube
- 2018
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Ingår i: Nature Physics. - : NATURE PUBLISHING GROUP. - 1745-2473 .- 1745-2481. ; 14:9, s. 961-966
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Tidskriftsartikel (refereegranskat)abstract
- Lorentz symmetry is a fundamental spacetime symmetry underlying both the standard model of particle physics and general relativity. This symmetry guarantees that physical phenomena are observed to be the same by all inertial observers. However, unified theories, such as string theory, allow for violation of this symmetry by inducing new spacetime structure at the quantum gravity scale. Thus, the discovery of Lorentz symmetry violation could be the first hint of these theories in nature. Here we report the results of the most precise test of spacetime symmetry in the neutrino sector to date. We use high-energy atmospheric neutrinos observed at the IceCube Neutrino Observatory to search for anomalous neutrino oscillations as signals of Lorentz violation. We find no evidence for such phenomena. This allows us to constrain the size of the dimension-four operator in the standard-model extension for Lorentz violation to the 10(-28) level and to set limits on higher-dimensional operators in this framework. These are among the most stringent limits on Lorentz violation set by any physical experiment.
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| 2. |
- Aartsen, M. G., et al.
(författare)
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Neutrino emission from the direction of the blazar TXS 0506+056 prior to the IceCube-170922A alert
- 2018
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 361:6398, s. 147-151
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Tidskriftsartikel (refereegranskat)abstract
- A high-energy neutrino event detected by IceCube on 22 September 2017 was coincident in direction and time with a gamma-ray flare from the blazar TXS 0506+056. Prompted by this association, we investigated 9.5 years of IceCube neutrino observations to search for excess emission at the position of the blazar. We found an excess of high-energy neutrino events, with respect to atmospheric backgrounds, at that position between September 2014 and March 2015. Allowing for time-variable flux, this constitutes 3.5 sigma evidence for neutrino emission from the direction of TXS 0506+056, independent of and prior to the 2017 flaring episode. This suggests that blazars are identifiable sources of the high-energy astrophysical neutrino flux.
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| 3. |
- Aartsen, M. G., et al.
(författare)
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Constraints on Galactic Neutrino Emission with Seven Years of IceCube Data
- 2017
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 849:1
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Tidskriftsartikel (refereegranskat)abstract
- The origins of high-energy astrophysical neutrinos remain a mystery despite extensive searches for their sources. We present constraints from seven years of IceCube Neutrino Observatory muon data on the neutrino flux coming from the Galactic plane. This flux is expected from cosmic-ray interactions with the interstellar medium or near localized sources. Two methods were developed to test for a spatially extended flux from the entire plane, both of which are maximum likelihood fits but with different signal and background modeling techniques. We consider three templates for Galactic neutrino emission based primarily on gamma-ray observations and models that cover a wide range of possibilities. Based on these templates and in the benchmark case of an unbroken E-2.5 power-law energy spectrum, we set 90% confidence level upper limits, constraining the possible Galactic contribution to the diffuse neutrino flux to be relatively small, less than 14% of the flux reported in Aartsen et al. above 1 TeV. A stacking method is also used to test catalogs of known high-energy Galactic gamma-ray sources.
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| 4. |
- Aartsen, M. G., et al.
(författare)
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Search for neutrinos from dark matter self-annihilations in the center of the Milky Way with 3 years of IceCube/DeepCore
- 2017
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Ingår i: European Physical Journal C. - : SPRINGER. - 1434-6044 .- 1434-6052. ; 77:9
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Tidskriftsartikel (refereegranskat)abstract
- We present a search for a neutrino signal from dark matter self-annihilations in the Milky Way using the Ice-Cube Neutrino Observatory (IceCube). In 1005 days of data we found no significant excess of neutrinos over the background of neutrinos produced in atmospheric air showers from cosmic ray interactions. We derive upper limits on the velocity averaged product of the darkmatter self-annihilation cross section and the relative velocity of the dark matter particles . Upper limits are set for darkmatter particle candidate masses ranging from 10GeV up to 1TeV while considering annihilation through multiple channels. This work sets the most stringent limit on a neutrino signal from dark matter with mass between 10 and 100GeV, with a limit of 1.18 . 10-23 cm(3)s(-1) for 100GeV dark matter particles self-annihilating via iota(+)iota(-) t-to neutrinos (assuming the Navarro-Frenk-White dark matter halo profile).
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| 5. |
- Aartsen, M. G., et al.
(författare)
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Search for Astrophysical Sources of Neutrinos Using Cascade Events in IceCube
- 2017
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 846:2
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Tidskriftsartikel (refereegranskat)abstract
- The IceCube neutrino observatory has established the existence of a flux of high-energy astrophysical neutrinos, which is inconsistent with the expectation from atmospheric backgrounds at a significance greater than 5 sigma. This flux has been observed in analyses of both track events from muon neutrino interactions and cascade events from interactions of all neutrino flavors. Searches for astrophysical neutrino sources have focused on track events due to the significantly better angular resolution of track reconstructions. To date, no such sources have been confirmed. Here we present the first search for astrophysical neutrino sources using cascades interacting in IceCube with deposited energies as small as 1 TeV. No significant clustering was observed in a selection of 263 cascades collected from 2010 May to 2012 May. We show that compared to the classic approach using tracks, this statistically independent search offers improved sensitivity to sources in the southern sky, especially if the emission is spatially extended or follows a soft energy spectrum. This enhancement is due to the low background from atmospheric neutrinos forming cascade events and the additional veto of atmospheric neutrinos at declinations less than or similar to-30 degrees.
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| 6. |
- Sargeson, A. M., et al.
(författare)
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Names and symbols for the transfermium elements
- 1997
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Ingår i: Pure and Applied Chemistry. - : Walter de Gruyter GmbH. - 0033-4545 .- 1365-3075. ; 69:12, s. 2471-2473
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Tidskriftsartikel (refereegranskat)abstract
- The recommendations (ref. 1) of the Commission on Nomenclature of Inorganic Chemistry (CNIC) on the nomenclature of the transfermium elements (101-109, inclusive) were considered by the IUPAC Bureau at Guildford (UK) in September 1995. As a result of the various criticisms of the recommendations and theway that they had been processed, the Bureau decided to adopt the recommendations as provisional and to circulate them to national/regional nomenclature centres in the normal way, with notices to be published innational/regional chemistry journals and magazines, requesting submission of comments to CNIC. In particular, the National Adhering Organizations (NAOs) were invited to express their views concerning the extant proposals for the names of these elements and the principles and traditions used to derive them. The response from the general chemical community was small, and the bulk of the replies came from nuclear scientists.
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| 7. |
- Sargeson, A. M., et al.
(författare)
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Names and symbols of transfermium elements (IUPAC recommendations 1994)
- 1994
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Ingår i: Pure and Applied Chemistry. - : Walter de Gruyter GmbH. - 0033-4545 .- 1365-3075. ; 66:12, s. 2419-2421
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Tidskriftsartikel (refereegranskat)abstract
- The Transfermium Working Group (TWG) was set up in 1986 under the joint auspices of the International Union of Pure and Applied Chemistry (IUPAC) and the International Union of Pure and Applied Physics (IUPAP). Its conclusions, duly endorsed by IUPAC and IUPAP, were published in the following three reports:1. Criteria that must be satisfied for the discovery of a new chemical element to be recognized, Pure & Appl. Chem., 63, 879-886 (1991).2. Discovery of the transfermium elements: Introduction to the discovery profiles, Pure & Appl. Chem., 65, 1757-1763 (1993).3, Discovery of the transfermium elements: Discovery profiles of the transfermium elements, Pure & Appl. Chem., 65, 1764-1814 (1993).IUPAC went a stage further by inviting responses on reports 2 and 3 from the three major groups concerned, i.e., Lawrence Berkeley Laboratory, California; Joint Institute for Nuclear Research, Dubna; and Gesellschaft fur Schwerionenforschung , Darmstadt. These responses together with the TWG's reply to the responses were published unedited in Pure & Appl. Chem.,Vol. 65, (1993), pp. 1815-1824.
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| 8. |
- Longinetti, E., et al.
(författare)
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SARS-COV2 exposure rates and serological response of people living with MS
- 2022
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Ingår i: Multiple Sclerosis Journal. - : Sage Publications. - 1352-4585 .- 1477-0970. ; 28:Suppl. 3, s. 515-516
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Introduction: Some multiple sclerosis (MS) disease-modifying therapies (DMTs) are associated with blunted humoral vaccination responses, but relevance for SARS-CoV-2 infection is unclear.Objectives: To determine SARS-CoV-2 exposure rates and formation of antibody memory among participants of the COMparison Between All immunoTherapies for MS (COMBAT-MS; NCT03193866) and the Immunomodulation and MS Epidemiology (IMSE) studies.Aim: To determine SARS-CoV2 serological response of people living with MS (pwMS).Methods: Using a multiplex bead-based assay we determined SARS-CoV-2 spike and nucleocapsid antibody levels in 3,723 pwMS in paired serum samples (n=7,157) donated prior (Results: Specificity and sensitivity of the assay for SARS-CoV-2 was 100% and 99.7%, respectively. The proportion of positive samples for SARS-CoV-2 differed moderately across DMTs with the highest values among cladribine-treated (7.4%) and the lowest number among rituximab-treated pwMS (3.9%). Similarly, the proportion of positive cases not reported in the Swedish MS registry varied from 100% for cladribine to 33.3% among untreated pwMS. Comparing levels of antibodies titers showed that levels were lower among those treated with rituximab or fingolimod vs interferon treated pwMS. Point estimates indicated a similar trend comparing rituximab or fingolimod vs untreated pwMS.Conclusions: Overall rates of SARS-CoV-2 antibody positivity after the first COVID-19 wave differed only moderately across DMTs, while antibody levels were lower with rituximab or fingolimod compared to interferon-treated pwMS. This indicates quantitative rather than qualitative differences in the humoral response to infection.
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