Single top quark detected

Same techniques could be used to detect theoretical particles like the Higgs boson

Physicists have identified the production of the elusive single top quark, two research teams report.

Previously top quarks have been observed only when produced in pairs, as when they were initially discovered 14 years ago at the Fermi National Accelerator Laboratory in Batavia, Ill. Now, researchers using Fermilab’s two detectors announced March 9 that they have detected single top quarks. The techniques used to find the singleton quarks could help to identify other rare particles, such as the Higgs boson, the scientists say.

“What a discovery,” comments Nobel laureate David Gross of the Kavli Institute for Theoretical Physics at the University of California, Santa Barbara. “These researchers should be congratulated.”

Quarks are fundamental particles of matter that come in six varieties known as “flavors.” Ordinary matter consists mostly of two quark flavors, the “up” and “down” quarks that make up protons and neutrons. Other quarks are found in exotic subatomic particles or are created in high-energy collisions in particle accelerators. The top quark was the last flavor to be discovered experimentally, in 1995.

Since that time, the two groups at Fermilab, using the CDF and the DZero detectors, have combed through data from billions upon billions of particle collisions, looking for the unique features that would signal a single top quark.

But only about one in every 20 billion collisions produces a single top quark, and that weak signal easily gets lost in the background of other particle debris. “Pairs of top quarks have a more distinctive signature than singles, and so are easier to distinguish,” explains physicist Darien Wood, a spokesman for the DZero group.

The two groups had slightly different methods of analyzing the data, which allowed for healthy competition, says physicist Robert Roser, a spokesman for the CDF group.  

A possible sighting of a top quark singleton in 2007 indicated that the scientists were on the right track. “But the evidence has to be solid to claim a discovery,” says Jacobo Konigsberg, a spokesman for CDF. “More data was needed to increase the statistical significance of our data.” 

The sophisticated data analysis used to find the singleton top quarks could help scientists make sense of the results of other particle collision experiments, the researchers say. “The single top is the first stepping stone to other unknowns, like the Higgs boson,” says Roser.

The Higgs is a so-far hypothetical particle that most theorists believe is necessary to endow other subatomic particles with mass. Its discovery is being pursued at Fermilab and is also a prime goal for the Large Hadron Collider, a particle accelerator near Geneva scheduled to begin particle collisions later this year.

“Succeeding in isolating single top quarks is a sign that the community is up to the Herculean task of finding the Higgs boson,” Gross says.

Use up and down arrow keys to explore.Use right arrow key to move into the list.Use left arrow key to move back to the parent list.Use tab key to enter the current list item.Use escape to exit the menu.Use the Shift key with the Tab key to tab back to the search input.
Logo

Looks like your ad blocker is on.

×

We rely on ads to keep creating quality content for you to enjoy for free.

Please support our site by disabling your ad blocker.

Continue without supporting us

Choose your Ad Blocker

  • Adblock Plus
  • Adblock
  • Adguard
  • Ad Remover
  • Brave
  • Ghostery
  • uBlock Origin
  • uBlock
  • UltraBlock
  • Other
  1. In the extension bar, click the AdBlock Plus icon
  2. Click the large blue toggle for this website
  3. Click refresh
  1. In the extension bar, click the AdBlock icon
  2. Under "Pause on this site" click "Always"
  1. In the extension bar, click on the Adguard icon
  2. Click on the large green toggle for this website
  1. In the extension bar, click on the Ad Remover icon
  2. Click "Disable on This Website"
  1. In the extension bar, click on the orange lion icon
  2. Click the toggle on the top right, shifting from "Up" to "Down"
  1. In the extension bar, click on the Ghostery icon
  2. Click the "Anti-Tracking" shield so it says "Off"
  3. Click the "Ad-Blocking" stop sign so it says "Off"
  4. Refresh the page
  1. In the extension bar, click on the uBlock Origin icon
  2. Click on the big, blue power button
  3. Refresh the page
  1. In the extension bar, click on the uBlock icon
  2. Click on the big, blue power button
  3. Refresh the page
  1. In the extension bar, click on the UltraBlock icon
  2. Check the "Disable UltraBlock" checkbox
  3. Marque la casilla de verificación "Desactivar UltraBlock"
  1. Please disable your Ad Blocker
  2. Disable any DNS blocking tools such as AdGuardDNS or NextDNS

If the prompt is still appearing, please disable any tools or services you are using that block internet ads (e.g. DNS Servers).