Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

COUPP experiment tightens limits on dark matter

15.02.2008
Physicists revive bubble chamber technology to search for WIMPs

Scientists working on the COUPP experiment at the Department of Energy’s Fermi National Accelerator Laboratory today (February 14) announced a new development in the quest to observe dark matter. The Chicagoland Observatory for Underground Particle Physics experiment tightened constraints on the “spin-dependent” properties of WIMPS, weakly interacting massive particles that are candidates for dark matter. Their results, combined with the findings of other dark matter searches, contradict the claims for the observation of such particles by the Dark Matter experiment (DAMA) in Italy and further restrict the hunting ground for physicists to track their dark matter quarry.

The COUPP experiment also proved that dusting off an old technology of particle physics, the bubble chamber, offers extraordinary potential as a tool in the search for dark matter.

“Our first results are extremely encouraging, and bubble-chamber technology is eminently scale-able,” said Juan Collar, a University of Chicago professor and spokesman of the COUPP collaboration, which includes 16 scientists and students from the University of Chicago; Indiana University South Bend; and DOE’s Fermilab. “We expect that COUPP will soon have a sweeping sensitivity to dark matter particles, simultaneously exploring both spin-dependent and spin-independent mechanisms for dark matter interaction. This is just one of the aspects that set our experiment apart from the competition.”

Physicists theorize that dark matter particles interact with ordinary matter via different mechanisms that are either dependent or independent of the nuclear spin of the atoms in the detector material.

Previous experiments had severely constrained the possibility that the DAMA observations result from dark matter spin-independent interactions. COUPP has now ruled out the last region of parameter space that allowed for a spin-dependent explanation. Several experiments worldwide, including DAMA itself, had been racing to prove or disprove DAMA’s initial claim to observe WIMPs. If the DAMA result had been due to spin-dependent WIMPs, then COUPP researchers should have found hundreds of WIMPs. They found none above background.

The COUPP collaboration details the results in a paper, “Improved Spin-Dependent WIMP Limits from a Bubble Chamber,” appearing in the February 15 issue of the journal Science.

WIMPs, if they exist, rarely interact with ordinary matter. COUPP uses a glass jar filled with about a liter of iodotrifluoromethane, a fire-extinguishing liquid known as CF3I, to detect a particle as it hits a nucleus, triggering evaporation of a small amount of CF3I. The resulting bubble initially is too small to see but it grows. Using digital cameras, COUPP scientists study the pictures of bubbles once they reach a millimeter in size. They look for statistical variations between photographs that signal whether bubbles were caused by background radiation or by dark matter.

“Eighty-five percent of the total matter of the universe still eludes direct detection,” said Dennis Kovar, acting associate director for high energy physics in the DOE Office of Science. “To discover the nature of dark matter will require both catching dark matter particles with innovative detectors like COUPP's and making and studying dark matter at particle accelerators.”

The COUPP experiment is located 350 feet underground in a tunnel on the Fermilab site.

“To search for WIMPs, COUPP revived one of the oldest tools in particle physics: the bubble chamber. As other detector technology surpassed the bubble chamber in the past two decades, it became nearly extinct in high-energy physics laboratories,” said James Whitmore, NSF program manager. “Now it is making a comeback in one of the most exciting areas of particle physics, the search for dark matter.”

Other experiments, such as the Cryogenic Dark Matter Search at Fermilab, look for dark matter underground using a different technology.

“COUPP’s use of a bubble chamber is an intriguing technology. It has been improving its reach for spin-dependent research,” said Blas Cabrera, Stanford University professor and CDMS spokesman. “It is a valuable tool in the range of technology in the search for dark matter. It is important to have confirmation from radically different technologies.”

“COUPP is a new player in an extremely competitive arena, and it has already demonstrated it can contribute to the search for dark matter,” said Hugh Montgomery, Fermilab associate director for research. “Now they need to show whether or not they can take it to the next level.”

COUPP aims to increase sensitivity by increasing the amount of liquid from one liter to 30 liters in the bubble chamber. Physicists expect soon to start testing the larger chamber at Fermilab. If the larger chamber meets expectations, the experiment could move to a deeper tunnel to reduce the background from cosmic radiation even further.

“No one knows for sure if dark matter is made of WIMPs,” said Andrew Sonnenschein, COUPP collaborator. “If it is, we'll have a chance with the new chamber to find it. That's all we can ask for.”

Tona Kunz | EurekAlert!
Further information:
http://www.fnal.gov

More articles from Physics and Astronomy:

nachricht Tracing aromatic molecules in the early universe
23.03.2017 | University of California - Riverside

nachricht New study maps space dust in 3-D
23.03.2017 | DOE/Lawrence Berkeley National Laboratory

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

When Air is in Short Supply - Shedding light on plant stress reactions when oxygen runs short

23.03.2017 | Life Sciences

Researchers use light to remotely control curvature of plastics

23.03.2017 | Power and Electrical Engineering

Sea ice extent sinks to record lows at both poles

23.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>