Hehn, L., Armengaud, E., Arnaud, Q. et al. (45 more authors) (2016) Improved EDELWEISS-III sensitivity for low-mass WIMPs using a profile likelihood approach. European Physical Journal C, 76 (10). 548. ISSN 1434-6044
Abstract
We report on a dark matter search for a Weakly Interacting Massive Particle (WIMP) in the mass range mχ∈[4,30]GeV/c2 with the EDELWEISS-III experiment. A 2D profile likelihood analysis is performed on data from eight selected detectors with the lowest energy thresholds leading to a combined fiducial exposure of 496 kg-days. External backgrounds from γ- and β-radiation, recoils from 206Pb and neutrons as well as detector intrinsic backgrounds were modelled from data outside the region of interest and constrained in the analysis. The basic data selection and most of the background models are the same as those used in a previously published analysis based on boosted decision trees (BDT) [1]. For the likelihood approach applied in the analysis presented here, a larger signal efficiency and a subtraction of the expected background lead to a higher sensitivity, especially for the lowest WIMP masses probed. No statistically significant signal was found and upper limits on the spin-independent WIMP-nucleon scattering cross section can be set with a hypothesis test based on the profile likelihood test statistics. The 90 % C.L. exclusion limit set for WIMPs with mχ=4GeV/c2 is 1.6×10-39cm2, which is an improvement of a factor of seven with respect to the BDT-based analysis. For WIMP masses above 15GeV/c2 the exclusion limits found with both analyses are in good agreement.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © The Author(s) 2016. This article is published with open access at Springerlink.com |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Department of Physics and Astronomy (Sheffield) |
Funding Information: | Funder Grant number SCIENCE AND TECHNOLOGY FACILITIES COUNCIL ST/K006444/1 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 02 Nov 2016 13:45 |
Last Modified: | 30 Jun 2020 08:06 |
Published Version: | http://dx.doi.org/10.1140/epjc/s10052-016-4388-y |
Status: | Published |
Publisher: | Springer Verlag |
Refereed: | Yes |
Identification Number: | 10.1140/epjc/s10052-016-4388-y |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:106845 |
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