Quantifying the evidence for Dark Matter in CoGeNT data

Davis, Jonathan H.; McCabe, Christopher; Boehm, Celine

Abstract

We perform an independent analysis of data from the CoGeNT direct detection experiment to quantify the evidence for dark matter recoils. We critically re-examine the assumptions that enter the analysis, focusing specifically on the separation of bulk and surface events, the latter of which constitute a large background. This separation is performed using the event rise-time, with the surface events being slower on average. We fit the rise-time distributions for the bulk and surface events with a log-normal and Pareto distribution (which gives a better fit to the tail in the bulk population at high rise-times) and account for the energy-dependence of the bulk fraction using a cubic spline. Using Bayesian and frequentist techniques and additionally investigating the effect of varying the rise-time cut, the bulk background spectrum and bin-sizes, we conclude that the CoGeNT data show a preference for light dark matter recoils at less than 1σ.

Citation

Davis, J. H., McCabe, C., & Boehm, C. (2014). Quantifying the evidence for Dark Matter in CoGeNT data. Journal of Cosmology and Astroparticle Physics, 2014(08), Article 014. https://doi.org/10.1088/1475-7516/2014/08/014

• Journal Article Type: Article
• Acceptance Date: Jul 15, 2014
• Online Publication Date: Aug 6, 2014
• Publication Date: Aug 6, 2014
• Deposit Date: Feb 3, 2016
• Publicly Available Date: Jun 6, 2018
• Journal: Journal of Cosmology and Astroparticle Physics
• Electronic ISSN: 1475-7516
• Publisher: IOP Publishing
• Peer Reviewed: Peer Reviewed
• Volume: 2014
• Issue: 08
• Article Number: 014
• DOI: https://doi.org/10.1088/1475-7516/2014/08/014
• Public URL: https://durham-repository.worktribe.com/output/1420805