Dark matter sleuths to design world's largest WIMP catcher

October 29, 2009

A team of researchers led by a Case Western Reserve University physicist is planning the world's largest, most sensitive experiment to catch the stuff of dark matter, stuff that's proved way beyond invisible.

The researchers are seeking WIMPs, short for weakly interacting massive particles, which aren't and don't act like atoms that comprise regular matter.

Scientists believe that WIMPs could have been born of the , stream through us by the billion every second and provide the mass needed to keep galaxies, including our Milky Way, from flying apart.

"We know there's dark matter, we just don't know what it is," said Tom Shutt, who holds the Agnar Pytte Chair of Physics at Case Western Reserve and is the principal investigator for the project.

Shutt's group, which merged with the group led by Physics Department Chairman Dan Akerib, has received a three-year, $3.2 million National Science Foundation grant to design a 20-ton liquid xenon WIMP detector, called LZD.

The group has proposed LZD as a major experiment for the Deep Underground Science and Engineering Laboratory, a national lab planned for the abandoned Homestake Gold Mine, nearly a mile beneath Lead, S.D.

The WIMP detector would be 2,000 times larger than the XENON 10 detector, a 10-kilogram prototype experiment in Gran Sasso, Italy, and 70 times larger than the 300 kilogram Large Underground Experiment, or LUX. The LUX project, led by Shutt and Brown University physicist Rick Gaitskell, will begin operating next year in South Dakota's Sanford Underground Science and Engineering Laboratory, also in the former Homestake mine.

Why build bigger?

"It's like using a larger light collector in a telescope," Akerib said. "It increases your chances of seeing what you want to see."

The 20-ton experiment would increase the chance of seeing a WIMP by more than 30,000 times over XENON 10, and more than 150 times over LUX because of increased size and sensitivity and longevity, Shutt explained.

WIMPs are hard to detect because they don't give off radiation. They don't interact with regular matter through electromagnetic forces, but pass through regular matter unimpeded, researchers believe.

That theory was bolstered by NASA's observations of two distant galaxies colliding in 2006. While a cloud of galactic gas dragged out from the friction of striking other regular matter, changes in gravity showed that dark matter had already passed through.

Shutt and Akerib say liquid xenon is the right stuff to catch a WIMP. The element is nearly completely inert, unpolarized and hard to polarize. Only dark matter particles can permeate into the inner region of the xenon liquid without being detected elsewhere, Shutt said.

What each experiment looks for is a chance strike: a WIMP knocking into a Xenon atom, something on the scale of a neutron colliding with the atom. The collision would produce a minute flash of light that supersensitive detectors would locate, amplify and analyze. In tests, LUX has detected the collision of single neutrons with liquid xenon atoms. LZD would be even more sensitive, by three orders of magnitude, giving the experiment an acuity akin to seeing an ant in the span of the Milky Way, Akerib said.

When LUX is lowered underground in 2010, the researchers will seek WIMPs. They will also field test their equipment and the underground lab and master the technology they expect to use in the 20-ton model.

Before attempting to build LZD, however, the research group wants an interim step. They are seeking funding for a 1.5 ton detector, called LZS.

The experiments are buried deep in the Earth for the same reason the Hubble Space Telescope was launched into orbit: to avoid interference. In orbit, Hubble is freed of Earth's obscuring atmosphere. Underground, WIMP experiments are shielded from hundreds of billions of charged particles that strike the surface of the earth annually, leaving the with a clear view should a WIMP strike.

What do we get out of this?

Detecting a WIMP would go a long way toward understanding how the universe works and confirm the theory that unseen matter must exist or galaxies would lack the mass to form, cluster and rotate as they do, Shutt said.

But the work goes beyond that.

"This is very much connected to big philosophical questions: What are we made of? What did we come from?" Akerib said.

Scientists expect the new technology could lead to another class of super-sensitive detectors for medicine and global security, including particle detectors that can tell what's happening in a distant nuclear facility and whether a country has or is building nuclear weapons.

The LUX and LZ projects compete with technologies that use germanium crystals frozen to nearly absolute zero or liquid argon detectors, in the race to find WIMPs. The groups will compete for funding to build their largest and best experiments.

Masahiro Morii, a physics professor at Harvard who helped build electronics for LUX, is among a growing number of researchers joining the xenon group. "Liquid xenon has a distinct advantage: it's straight forward to scale up," Morii said. And, "It's ahead of the other technologies by 3 to 5 years."

Source: Case Western Reserve University (news : web)


Rank 4 /5 (6 votes)
Related Stories
Relevant PhysicsForums posts
  • Strength of induced magnetic field inside an inductor
    created2 hours ago
  • Physical laws .... are they material?!!
    created3 hours ago
  • increasing time of daylight
    created3 hours ago
  • Light & Sight
    created4 hours ago
  • Wind Turbine Power
    created7 hours ago
  • Steam Table issues
    created9 hours ago
  • More from Physics Forums - General Physics

More news stories

Putting the squeeze on planets outside our solar system

(PhysOrg.com) -- Using high-powered lasers, scientists at Lawrence Livermore National Laboratory and collaborators discovered that molten magnesium silicate undergoes a phase change in the liquid state, abruptly ...

Physics / Condensed Matter

created 3 hours ago | popularity 5 / 5 (1) | comments 0 | with audio podcast

Hovering not hard if you're top-heavy, researchers find

Top-heavy structures are more likely to maintain their balance while hovering in the air than are those that bear a lower center of gravity, researchers at New York University's Courant Institute of Mathematical Sciences ...

Physics / General Physics

created 4 hours ago | popularity 5 / 5 (1) | comments 1 | with audio podcast

SLAC, Stanford team focuses on high-energy electrons to treat cancer

Accelerator physicists at SLAC and cancer specialists from Stanford are working on a new technology that could dramatically reduce the time needed for cancer radiation treatments. The team ran an initial experiment ...

Physics / General Physics

created 7 hours ago | popularity 5 / 5 (1) | comments 0

Measurements from high-energy collisions lead to better understanding of why meson particles disappear

For several years, physicists at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL), USA, have studied an unusual state of matter called the quark–gluon plasma, which they ...

Physics / General Physics

created 7 hours ago | popularity 5 / 5 (1) | comments 0

Quantum physicist explains $100K offer for proof scaled-up quantum computing is impossible

(PhysOrg.com) -- MIT researcher Scott Aaronson has certainly riled the physics community with his offer this past Friday, of $100,000 to anyone who can prove that scaled-up quantum computing is impossible. ...

Physics / Quantum Physics

created Feb 08, 2012 | popularity 4.1 / 5 (11) | comments 32 | with audio podcast weblog


Complex wiring of the nervous system may rely on a just a handful of genes and proteins

Researchers at the Salk Institute have discovered a startling feature of early brain development that helps to explain how complex neuron wiring patterns are programmed using just a handful of critical genes. ...

CIA website offline, Anonymous takes credit

The website of the Central Intelligence Agency was unresponsive on Friday after the hacker group Anonymous claimed to have knocked it offline.

Q&A: Obama and the birth control controversy

(AP) -- What birth control debate? A half-century after the introduction of the pill, acceptance of birth control by American women is virtually universal.

The power of estrogen -- male snakes attract other males

A new study has shown that boosting the estrogen levels of male garter snakes causes them to secrete the same pheromones that females use to attract suitors, and turned the males into just about the sexiest ...

New error-correcting codes guarantee the fastest possible rate of data transmission

Error-correcting codes are one of the triumphs of the digital age. They’re a way of encoding information so that it can be transmitted across a communication channel — such as an optical fiber o ...

Humans may have helped the decline of African rainforests 3000 years ago

(PhysOrg.com) -- Large areas of rainforests in Central Africa mysteriously disappeared over three thousand years ago, to be replaced by savannas. The prevailing theory has been that the cause was a change ...