The Academia Sinica-based Taiwan Experiment On Neutrino (TEXONO) Collaboration led by the Institute of Physics recently reported research results that refute evidence presented by the Coherent Germanium Neutrino Telescope (CoGeNT) Collaboration on the detection of dark matter. The related article was published in the prestigious journal Physical Review Letters on 25 June, 2013.

　　There is compelling evidence that about 95% of the energy density of the Universe is made up of dark matter and dark energy. However, the experimental search for dark matter and dark energy has proved challenging, and has become an important frontier in contemporary physics and cosmology.

　　In 2011, the US-based CoGeNT Collaboration reported data that could be interpreted as evidence for the detection of dark matter. If confirmed, this evidence would constitute a revolutionary discovery and therefore requires rigorous verification. The TEXONO Collaboration successfully took up this challenge. Using advanced low-energy germanium detectors at the low-background facilities at the “Kuo-Sheng Reactor Neutrino Laboratory” in northern Taiwan, the research team devised novel calibration schemes and data analysis techniques to enhance experimental sensitivity. New results from the TEXONO investigation refute the evidence of dark matter in the region implied by the CoGeNT data, and indicate deficiencies in the original data analysis procedures. The principal technical advance of this work is on the measurement of efficiency in the rejection of background events.

　　Founded in 1997, the TEXONO Collaboration consists of research institutes from Taiwan, China, India and Turkey, and is led by the Institute of Physics, Academia Sinica. The group pioneered techniques on the study of dark matter and strives to advance detector performance and physics sensitivities via hardware upgrades and background reduction. It built and commissioned the “Kuo-Sheng Reactor Neutrino Laboratory” at Nuclear Power Station II on the northern coast of Taiwan in 2000. TEXONO has achieved world-class results in studies of neutrino magnetic moments and neutrino electroweak physics, and launched an additional dark matter research program in 2004. The Collaboration has been working with Tsinghua University in China since 2009 to conduct the first dark matter experiment at the “China Jinping Underground Laboratory” in Sichuan, which is the deepest operating underground laboratory in the world and provides excellent shielding against the radiation background from cosmic rays. The newly reported results further establish TEXONO as a frontline contender in the quest for dark matter.

　　Funding for the current research was provided by the Academia Sinica Principal Investigator Award, the National Science Council of Taiwan, and the Scientific and Technological Research Council of Turkey.

　　The full article, titled “Limits on Spin-Independent Couplings of WIMP Dark Matter with a p-Type Point-Contact Germanium Detector”, can be found at the Physical Review Letters website at: http://prl.aps.org/pdf/PRL/v110/i26/e261301

　　Related Website:
TEXONO Collaboration Home-Page: http://hepmail.phys.sinica.edu.tw/~texono