Scientists across China and the United States collaborating on the PandaX search for dark matter from an underground lab in southwestern China report results from the first stage of the experiment in a new study published in the Beijing-based journal SCIENCE CHINA Physics, Mechanics & Astronomy.
PandaX is the first dark matter experiment in China that deploys more than one hundred kilograms of xenon as a detector; the project is designed to monitor potential collisions between xenon nucleons and weakly interactive massive particles, hypothesized candidates for dark matter.
In the new study, scientists explain, "Dark matter is a leading candidate to explain gravitational effects observed in galactic rotational curves, galaxy clusters, and large scale structure formation."
"Weakly interacting massive particles (WIMPs), a particular class of dark matter candidates, are interesting in particle physics and can be studied in colliders [and in] indirect and direct detection experiments."
If confirmed, dark matter particles would extend understanding of the fundamental building blocks of nature beyond the Standard Model of particle physics, and would provide support for theories on supersymmetry and extra dimensions of space-time.
"Direct positive detection of WIMPs using ultra-low background detectors in deep underground laboratories would provide convincing evidence of dark matter in our solar system and allow the probing of fundamental properties of WIMPs," they add in the new study.
Direct detection experiments using different technologies have produced many interesting results, but not universally confirmed evidence of weakly interacting massive particles. These results have produced much excitement across the global scientific community and call for further examination of WIMP signals through other experiments.
"In recent years, new techniques using noble liquids (xenon, argon) have shown exceptional potential due to the capability of background suppression and discrimination, and scalability to large target masses," state the PandaX collaborators. "The XENON10/100 and LUX experiments using the dual-phase technique have improved WIMP detection sensitivity by more than two orders of magnitude in a wide mass range."
China's PandaX experiment, operated at the China Jinping Underground Laboratory, uses the dual-phase xenon technique to search for both low and high mass WIMP dark matter.
The initial success of the PandaX project demonstrates China has joined the global competition at the scientific frontier marking dark matter searches.
Today more than twenty dark matter search experiments are being conducted worldwide. Many dark matter search experiments, such as the DAMA/LIBRA experiment in Italy, the CoGeNT and CDMS experiments in the US, and the German-led CRESST experiment have reported findings that could be interpreted as positive signals of dark matter in recent years.
The PandaX collaboration joins this effort with results from a dark matter search that started in May of 2014.
No dark matter signal was observed in the first PandaX-I run, which places strong constraints on all previously reported dark matter-like signals from other similar types of experiments.
The PandaX experiment to date has collected about 4 million raw events; only about ten thousand events fell into the energy region of interest for dark matter. In the quiet central part of the xenon target only 46 events were observed.
However, the data from these 46 events was consistent with signals marking background radiation, not dark matter.
PandaX stands for Particle and Astrophysical Xenon Detector. The experiment is being conducted by an international team of about 40 scientists, and led by researchers from Shanghai Jiao Tong University.
The goal of the first stage of PandaX experiment is to examine previously reported dark matter-like signals. The scale of the PandaX-I experiment is second only to that of LUX, which is currently the planet's largest dark matter experiment and is located in a South Dakota mine in the US.
To shield the Chinese experiment from cosmic rays, the PandaX detector is located at the China Jinping Underground Laboratory (CJPL), the deepest underground laboratory in the world. CJPL was developed by Tsinghua University and the Yalong River Hydropower Development Company in 2010.
This research was supported by the 985-III grant from Shanghai Jiao Tong University, the National Basic Research Program of China from the Ministry of Science and Technology of China (Grant No. 2010CB833005), the National Natural Science Foundation of China (Grant No. 11055003) and the Office of Science and Technology in the Shanghai Municipal Government (Grant No. 11DZ2260700). Shandong University, Peking University, the University of Maryland, and the University of Michigan also sponsored the project.
See the article: Xiao M J, Xiao X, Zhao L, et al. First dark matter search results from the PandaX-I experiment. Sci China-Phys Mech Astron, 2014, 57: 2024-2030, doi: 10.1007/s11433-014-5598-7
SCIENCE CHINA Physics, Mechanics & Astronomy is produced by Science China Press, a leading publisher of scientific journals in China that operates under the auspices of the Chinese Academy of Sciences. Science China Press presents to the world leading-edge advances made by Chinese scientists across a spectrum of fields. http://www.scichina.com/english/
Ji Xiangdong | Eurek Alert!
Witnessing turbulent motion in the atmosphere of a distant star
23.08.2017 | Max-Planck-Institut für Radioastronomie
Heating quantum matter: A novel view on topology
22.08.2017 | Université libre de Bruxelles
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
23.08.2017 | Life Sciences
23.08.2017 | Life Sciences
23.08.2017 | Physics and Astronomy