Featured Research

from universities, journals, and other organizations

Physicists discover new way to produce antimatter-containing atom

Date:
July 11, 2011
Source:
University of California - Riverside
Summary:
Physicists report that they have discovered a new way to create positronium, an exotic and short-lived atom that could help answer what happened to antimatter in the universe, why nature favored matter over antimatter at the universe's creation. The method works at almost any temperature -- including very low temperatures.

Researchers Tomu H. Hisakado, Harry Tom, Allen Mills and David Cassidy have found a new way to produce positronium.
Credit: M. Kelley, UCR Strategic Communications

Physicists at the University of California, Riverside report that they have discovered a new way to create positronium, an exotic and short-lived atom that could help answer what happened to antimatter in the universe, why nature favored matter over antimatter at the universe's creation.

Related Articles


Positronium is made up of an electron and its antimatter twin, the positron. It has applications in developing more accurate Positron Emission Tomography or PET scans and in fundamental physics research.

Recently, antimatter made headlines when scientists at CERN, the European Organisation for Nuclear Research, trapped antihydrogen atoms for more than 15 minutes. Until then, the presence of antiatoms was recorded for only fractions of a second.

In the lab at UC Riverside, the physicists first irradiated samples of silicon with laser light. Next they implanted positrons on the surface of the silicon. They found that the laser light frees up silicon electrons that then bind with the positrons to make positronium.

"With this method, a substantial amount of positronium can be produced in a wide temperature range and in a very controllable way," said David Cassidy, an assistant project scientist in the Department of Physics and Astronomy, who performed the research along with colleagues. "Other methods of producing positronium from surfaces require heating the samples to very high temperatures. Our method, on the other hand, works at almost any temperature -- including very low temperatures."

Cassidy explained that when positrons are implanted into materials, they can sometimes get stuck on the surface, where they will quickly find electrons and annihilate.

"In this work, we show that irradiating the surface with a laser just before the positrons arrive produces electrons that, ironically, help the positrons to leave the surface and avoid annihilation," said Allen Mills, a professor of physics and astronomy, in whose lab Cassidy works. "They do this by forming positronium, which is spontaneously emitted from the surface. The free positronium lives more than 200 times longer than the surface positrons, so it is easy to detect."

Study results appear in the July 15 issue of Physical Review Letters.

The researchers chose silicon in their experiments because it has wide application in electronics, is robust, cheap and works efficiently.

"Indeed, at very low temperatures, silicon may be the best thing there is for producing positronium, at least in short bursts," Cassidy said.

The researchers' eventual goal is to perform precision measurements on positronium in order to better understand antimatter and its properties, as well as how it might be isolated for longer periods of time.

Cassidy and Mills were joined in the research by Harry Tom, a professor and the chair of physics and astronomy, and Tomu H. Hisakado, a graduate student in Mills's lab.

In the near future, this research team hopes to cool the positronium down to lower energy emission levels for other experimental uses, and create also a "Bose-Einstein condensate" for positronium -- a collection of positronium atoms that are in the same quantum state.

"The creation of a Bose-Einstein condensate of positronium would really push the boundaries of what is possible in terms of real precision measurements," Cassidy said. "Such measurements would shed more light on the properties of antimatter and may help us probe further into why there is asymmetry between matter and antimatter in the universe."

Grants from the National Science Foundation and the US Air Force Research Laboratory funded the study.


Story Source:

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


Journal Reference:

  1. D. B. Cassidy, T. H. Hisakado, H. W. K. Tom, and A. P. Mills Jr. Photoemission of positronium from Si. Physical Review Letters, 2011; (in press)

Cite This Page:

University of California - Riverside. "Physicists discover new way to produce antimatter-containing atom." ScienceDaily. ScienceDaily, 11 July 2011. <www.sciencedaily.com/releases/2011/07/110711172229.htm>.
University of California - Riverside. (2011, July 11). Physicists discover new way to produce antimatter-containing atom. ScienceDaily. Retrieved March 6, 2015 from www.sciencedaily.com/releases/2011/07/110711172229.htm
University of California - Riverside. "Physicists discover new way to produce antimatter-containing atom." ScienceDaily. www.sciencedaily.com/releases/2011/07/110711172229.htm (accessed March 6, 2015).

Share This


More From ScienceDaily



More Matter & Energy News

Friday, March 6, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Gas Production Cut on Earthquake Fears

Gas Production Cut on Earthquake Fears

Reuters - Business Video Online (Mar. 5, 2015) The Dutch government has cut production at Europe&apos;s largest gas field in Groningen amid concerns over earthquakes which are damaging local churches. As Amy Pollock reports the decision - largely politically-motivated - could have big economic conseqeunces. Video provided by Reuters
Powered by NewsLook.com
Star Wars-Inspired Prototype Creates Holographic Display

Star Wars-Inspired Prototype Creates Holographic Display

Reuters - Innovations Video Online (Mar. 5, 2015) A prototype holographic display named Leia - after the Star Wars princess who appeared in holographic form asking Obi-Wan Kenobu for help - is demonstrated at the Mobile World Congress in Barcelona. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
IKEA and Samsung Launch Embedded Wireless Charging Range

IKEA and Samsung Launch Embedded Wireless Charging Range

Reuters - Innovations Video Online (Mar. 5, 2015) Samsung and IKEA hope their new embedded wireless charging products, launched at Barcelona&apos;s Mobile World Congress, will tempt consumers eager for plugless power. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com
Samsung Unveils $30,000 'Dream Doghouse'

Samsung Unveils $30,000 'Dream Doghouse'

Buzz60 (Mar. 5, 2015) On display at the Crufts dog show in England, the &apos;dog kennel of the future&apos; comes with features like a doggie treadmill and Samsung tablet. Mike Janela (@mikejanela) has more. Video provided by Buzz60
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