Free Newsletters - Space News - Defense Alert - Environment Report - Energy Monitor
. 24/7 Space News .




TIME AND SPACE
Scientists complete the top quark puzzle
by Staff Writers
Chicago IL (SPX) Feb 27, 2014


This diagram shows the process for creating single top quarks through the s-channel. A quark from an incoming proton interacts in the Tevatron with an antiquark from an incoming antiproton, forming a W boson with much greater mass. This W boson then decays into a top quark and an antibottom quark, which can be seen in the CDF and DZero detectors. Visit this page for more data. Image courtesy Fermilab.

Scientists on the CDF and DZero experiments at the U.S. Department of Energy's Fermi National Accelerator Laboratory have announced that they have found the final predicted way of creating a top quark, completing a picture of this particle nearly 20 years in the making.

The two collaborations jointly announced on Friday, Feb. 21, that they had observed one of the rarest methods of producing the elementary particle - creating a single top quark through the weak nuclear force, in what is called the "s-channel."

For this analysis, scientists from the CDF and DZero collaborations sifted through data from more than 500 trillion proton-antiproton collisions produced by the Tevatron from 2001 to 2011. They identified about 40 particle collisions in which the weak nuclear force produced single top quarks in conjunction with single bottom quarks.

Top quarks are the heaviest and among the most puzzling elementary particles. They weigh even more than the Higgs boson - as much as an atom of gold - and only two machines have ever produced them: Fermilab's Tevatron and the Large Hadron Collider at CERN.

There are several ways to produce them, as predicted by the theoretical framework known as the Standard Model, and the most common one was the first one discovered: a collision in which the strong nuclear force creates a pair consisting of a top quark and its antimatter cousin, the anti-top quark.

Collisions that produce a single top quark through the weak nuclear force are rarer, and the process scientists on the Tevatron experiments have just announced is the most challenging of these to detect. This method of producing single top quarks is among the rarest interactions allowed by the laws of physics. The detection of this process was one of the ultimate goals of the Tevatron, which for 25 years was the most powerful particle collider in the world.

"This is an important discovery that provides a valuable addition to the picture of the Standard Model universe," said James Siegrist, DOE associate director of science for high energy physics. "It completes a portrait of one of the fundamental particles of our universe by showing us one of the rarest ways to create them."

Searching for single top quarks is like looking for a needle in billions of haystacks. Only one in every 50 billion Tevatron collisions produced a single s-channel top quark, and the CDF and DZero collaborations only selected a small fraction of those to separate them from background, which is why the number of observed occurrences of this particular channel is so small. However, the statistical significance of the CDF and DZero data exceeds that required to claim a discovery.

"Kudos to the CDF and DZero collaborations for their work in discovering this process," said Saul Gonzalez, program director for the National Science Foundation. "Researchers from around the world, including dozens of universities in the United States, contributed to this important find."

The CDF and DZero experiments first observed particle collisions that created single top quarks through a different process of the weak nuclear force in 2009. This observation was later confirmed by scientists using the Large Hadron Collider.

Scientists from 27 countries collaborated on the Tevatron CDF and DZero experiments and continue to study the reams of data produced during the collider's run, using ever more sophisticated techniques and computing methods.

"I'm pleased that the CDF and DZero collaborations have brought their study of the top quark full circle," said Fermilab Director Nigel Lockyer. "The legacy of the Tevatron is indelible, and this discovery makes the breadth of that research even more remarkable."

.


Related Links
Fermi National Accelerator Laboratory
Understanding Time and Space






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





TIME AND SPACE
Optimising custody is child's play for physicists
Heidelberg, Germany (SPX) Feb 26, 2014
Physics can provide insights into societal trends. Problems involving interactions between people linked in real-life networks can be better understood by using physical models. As a diversion from his normal duties as a theoretical physicist, Andres Gomberoff from the Andres Bello University in Santiago, Chile, set out to resolve one of his real-life problems: finding a suitable weekend f ... read more


TIME AND SPACE
China Focus: Uneasy rest begins for China's troubled Yutu rover

China's Lunar Lander Still Operational

Is Yutu Stuck?

Japan's Pocari Sweat bound for the moon: maker

TIME AND SPACE
NASA's Curiosity Mars Rover Views Striated Ground

NASA Mars Orbiter Views Opportunity Rover on Ridge

Curiosity Adds Reverse Driving for Wheel Protection

Curiosity Drives On After Crossing Martian Dune

TIME AND SPACE
Last Shuttle Commander Virtually Flies Boeing CST-100 to ISS

DARPA Open Catalog Makes Agency-Sponsored Software and Publications Available to All

India unveils its own astronaut crew capsule, plans test launch

Orion Underway Recovery Testing Begins off the Coast of California

TIME AND SPACE
The Next Tiangong

No Call for Yutu

What's up, Yutu

China's Jade Rabbit rover comes 'back to life'

TIME AND SPACE
Cosmonauts on space station to turn teacher for Russian students

Space suit leak happened before, NASA admits

NASA Seeks US Industry Feedback on Options for Future ISS Cargo Services

NASA, International Space Station Partners Announce Future Crew Members

TIME AND SPACE
Russia to Start Building New Manned Rocket Launch Pad in 2015

New Vostochny space center a key priority for Russian Far East

First Copernicus satellite at launch site

'Mission of Firsts' Showcased New Range-Safety Technology at NASA Wallops

TIME AND SPACE
Kepler Mission Announces a Planet Bonanza, 715 New Worlds

Detection of Water Vapor in the Atmosphere of a Hot Jupiter

Water is Detected in a Planet Outside Our Solar System

NASA cries planetary 'bonanza' with 715 new worlds

TIME AND SPACE
Penn Researchers 'Design for Failure' With Model Material

In the eye of a chicken, a new state of matter comes into view

USAF reveals 'neighborhood watch' satellite program

Science publisher fooled by gibberish papers




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.