Improved EDELWEISS-III sensitivity for low-mass WIMPs using a profile likelihood approach

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A90072%2F16%3A00344170" target="_blank" >RIV/68407700:90072/16:00344170 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1140/epjc/s10052-016-4388-y" target="_blank" >https://doi.org/10.1140/epjc/s10052-016-4388-y</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1140/epjc/s10052-016-4388-y" target="_blank" >10.1140/epjc/s10052-016-4388-y</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Improved EDELWEISS-III sensitivity for low-mass WIMPs using a profile likelihood approach

Popis výsledku v původním jazyce

We report on a dark matter search for a Weakly Interacting Massive Particle (WIMP) in the mass range m(chi) is an element of [4, 30] GeV/c(2) 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 gamma- and beta-radiation, recoils from Pb-206 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 m(chi) = 4 GeV/c(2) is 1.6 x 10(-39) cm(2), which is an improvement of a factor of seven with respect to the BDT-based analysis. For WIMP masses above 15 GeV/c(2) the exclusion limits found with both analyses are in good agreement.

Název v anglickém jazyce

Improved EDELWEISS-III sensitivity for low-mass WIMPs using a profile likelihood approach

Popis výsledku anglicky

We report on a dark matter search for a Weakly Interacting Massive Particle (WIMP) in the mass range m(chi) is an element of [4, 30] GeV/c(2) 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 gamma- and beta-radiation, recoils from Pb-206 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 m(chi) = 4 GeV/c(2) is 1.6 x 10(-39) cm(2), which is an improvement of a factor of seven with respect to the BDT-based analysis. For WIMP masses above 15 GeV/c(2) the exclusion limits found with both analyses are in good agreement.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

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OECD FORD obor

10303 - Particles and field physics

Projekt

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Návaznosti

—

Rok uplatnění

2016

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

European Physical Journal C

ISSN

1434-6044

e-ISSN

1434-6052

Svazek periodika

76

Číslo periodika v rámci svazku

10

Stát vydavatele periodika

DE - Spolková republika Německo

Počet stran výsledku

10

Strana od-do

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Kód UT WoS článku

000385249500005

EID výsledku v databázi Scopus

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