Featured Research

from universities, journals, and other organizations

New Class Of Superweak Particles May Reveal Secrets Of Hidden Mass In Universe

Date:
July 9, 2003
Source:
University Of California - Irvine
Summary:
A UC Irvine study has revealed a new class of cosmic particles that may shed light on the composition of dark matter in the universe. These particles, called superweakly interacting massive particles, or superWIMPs, may constitute the invisible matter that makes up as much as one-quarter of the universe's mass.

Irvine, Calif., July 8, 2003 -- A UC Irvine study has revealed a new class of cosmic particles that may shed light on the composition of dark matter in the universe.

Related Articles


These particles, called superweakly interacting massive particles, or superWIMPs, may constitute the invisible matter that makes up as much as one-quarter of the universe's mass.

UCI physicists Jonathan Feng, Arvind Rajaraman and Fumihiro Takayama report that these new superWIMPs have radically different properties from weakly interacting massive particles (WIMPs), which many researchers have long looked to as the leading dark matter candidate. The study was posted July 3 on the online version of Physical Review Letters (http://prl.aps.org/).

The identity of dark matter is one of the most puzzling problems for those who study the nature of our cosmos. While as much as a quarter of the universe is made of this invisible mass, which plays a vital role in the structure of the universe, almost nothing is known about its composition. It is believed to be the celestial glue that holds galaxies together in their distinctive spiral shapes.

To identify this elusive dark matter, many astrophysical researchers have turned to WIMPs. These particles emit no light and are very difficult to detect. However, as their name suggests, they do have weak-force interactions with other particles, and they are expected to leave visible traces in experiments. Currently, research groups throughout the world are searching for WIMPs, so far without success. But in studying theories that predict WIMP dark matter, Feng and his colleagues found that in many of these theories WIMPs do not live forever. According to Feng, many theorists have assumed WIMPs to be the lightest particles and thus the most stable. "But we've found that WIMPs are often not stable at all, because they can decay into lighter particles," Feng said, "and, all of a sudden, the WIMPs disappear."

These new, lighter particles are superWIMPs. Like their progenitors, they emit no light and have both mass and gravitational force. But they are incapable of the type of weak-force interactions that WIMPs have; they can only interact gravitationally. Since the gravitational force is not as strong as the weak force, these interactions are, as Feng calls them, "superweak." In turn, these particles will rarely, if ever, collide with other particles.

And, unlike WIMPs, superWIMPs are incapable of decaying into other particles. "They are absolutely stable," Feng said. "And because of this, they are a completely different, but perfectly viable, alternative for dark matter."

Like WIMPs, superWIMPs only exist theoretically. In fact, because superWIMPs do not have weak-force interactions, they are predicted to be impossible to detect by conventional experimental methods. But Feng and his colleagues point to some alternative tests to prove their existence. They found that observations of old stars and the cosmic microwave background of the universe can reveal clues for superWIMPs.

"One place to look for evidence is in the cosmic microwave background, which in essence is the afterglow of the Big Bang," Feng said. "This background is very uniform. But according to our theory, WIMP decay would set loose a zoo of particles that would create deviations in this background. If such deviations are found, they would provide a particle fingerprint for the existence of superWIMP dark matter."

Feng and his collaborators are currently investigating hints for superWIMPs in present data and are considering further studies that might provide evidence for the existence of superWIMP dark matter.

The research was funded by UC Irvine and a CAREER Award from the National Science Foundation.


Story Source:

The above story is based on materials provided by University Of California - Irvine. Note: Materials may be edited for content and length.


Cite This Page:

University Of California - Irvine. "New Class Of Superweak Particles May Reveal Secrets Of Hidden Mass In Universe." ScienceDaily. ScienceDaily, 9 July 2003. <www.sciencedaily.com/releases/2003/07/030709064512.htm>.
University Of California - Irvine. (2003, July 9). New Class Of Superweak Particles May Reveal Secrets Of Hidden Mass In Universe. ScienceDaily. Retrieved November 1, 2014 from www.sciencedaily.com/releases/2003/07/030709064512.htm
University Of California - Irvine. "New Class Of Superweak Particles May Reveal Secrets Of Hidden Mass In Universe." ScienceDaily. www.sciencedaily.com/releases/2003/07/030709064512.htm (accessed November 1, 2014).

Share This



More Space & Time News

Saturday, November 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Antares Liftoff Explosion

Raw: Antares Liftoff Explosion

AP (Oct. 29, 2014) Observers near Wallops Island recorded what they thought would be a routine rocket launch Tuesday night. What they recorded was a major rocket explosion shortly after lift off. (Oct 29) Video provided by AP
Powered by NewsLook.com
Raw: Russian Cargo Ship Docks at Space Station

Raw: Russian Cargo Ship Docks at Space Station

AP (Oct. 29, 2014) Just hours after an American cargo run to the International Space Station ended in flames, a Russian supply ship has arrived at the station with a load of fresh supplies. (Oct. 29) Video provided by AP
Powered by NewsLook.com
Journalist Captures Moment of Antares Rocket Explosion

Journalist Captures Moment of Antares Rocket Explosion

Reuters - US Online Video (Oct. 29, 2014) A space education journalist is among those who witness and record the explosion of an unmanned Antares rocket seconds after its launch. Rough Cut (no reporter narration) Video provided by Reuters
Powered by NewsLook.com
Rocket Explosion Under Investigation

Rocket Explosion Under Investigation

AP (Oct. 28, 2014) NASA and Orbital Sciences officials say they are investigating the explosion of an unmanned commercial supply rocket bound for the International Space Station. It blew up moments after liftoff Tuesday evening over the launch site in Virginia. (Oct. 28) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins