17-22 July 2016
Master Cutlers Hall
Europe/London timezone

A low-mass dark matter search using ionization signals in XENON100

18 Jul 2016, 15:20
20m
Venue: Cutlers' Main Hall (First Floor); Chair: Chamkaur Ghag; Session Manager: Andrew Scarff ()

Venue: Cutlers' Main Hall (First Floor); Chair: Chamkaur Ghag; Session Manager: Andrew Scarff

Speaker

Mr. Andrea Tiseni (Nikhef)

Description

XENON100 is a liquid xenon dual phase time projection chamber (TPC) built to search for rare collisions with WIMP particles. The TPC detection principle allows for measurements of WIMP-induced recoils through two signals: a prompt scintillation signal and an ionization signal. In previous XENON100 analyses the recoil energy was determined using the size of the scintillation signal. WIMPs with a mass below 10 GeV/c$^{2}$ create recoils only up to a few keV, resulting in an ionisation signal lower than a few hundred photoelectrons and a scintillation signal that is often not detectable. By dropping the requirement of a scintillation signal and using only the ionization signal to determine the interaction energy, we perform a low-mass dark matter search using an exposure of 30 kg x yr, corresponding to the data acquired between February 28th, 2011 and March 31st, 2012. We lowered the energy threshold for detection to 0.7 keV for nuclear recoils using only the ionisation signal, searching for dark matter induced nuclear recoils in the energy interval between 0.7 keV and 9.1 keV. Because a complete background model cannot be constructed without a scintillation signal, an exclusion limit is computed under the assumption that every event passing our selection criteria could be a dark matter event. We derive a limit on the spin-independent WIMP-nucleon cross section that excludes WIMPs with a mass of 6 GeV/c$^{2}$ above $1.2 x 10^{-41}$ cm$^{2}$ at 90 % confidence level.

Primary author

Mr. Andrea Tiseni (Nikhef)

Presentation Materials

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