Event categories in the EDELWEISS WIMP search experiment

Abstract

Four categories of events have been identified in the EDELWEISS-I dark matter experiment using germanium cryogenic detectors measuring simultaneously charge and heat signals. These categories of events are interpreted as electron and nuclear interactions occurring in the volume of the detector, and electron and nuclear interactions occurring close to the surface of the detectors(10-20 mu-m of the surface). We discuss the hypothesis that low energy surface nuclear recoils,which seem to have been unnoticed by previous WIMP searches, may provide an interpretation of the anomalous events recorded by the UKDMC and Saclay NaI experiments. The present analysis points to the necessity of taking into account surface nuclear and electron recoil interactions for a reliable estimate of background rejection factors.

11 pages, submitted to Phys. Lett. B

References in corpus (5)

• The CRESST Dark Matter Search
• Discrimination between Nuclear Recoils and Electron Recoils by Simultaneous Detection of Phonons and Scintillation Light
• New limits on dark--matter WIMPs from the Heidelberg--Moscow experiment
• Characteristics of Alpha, Gamma and Nuclear Recoil Pulses from NaI(Tl) at 10-100 keV Relevant to Dark Matter Searches
• Status of the EDELWEISS Experiment

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• SICANE: a Detector Array for the Measurement of Nuclear Recoil Quenching Factors using Monoenergetic Neutron Beam
• Calibration of the EDELWEISS Cryogenic Heat-and-ionisation Germanium Detectors for Dark Matter Search
• Background discrimination capabilities of a heat and ionization germanium cryogenic detector
• WIMP direct detection overview
• The EDELWEISS Experiment : Status and Outlook