Featured Research

from universities, journals, and other organizations

Particle Oddball Surprises Physicists

Date:
March 19, 2009
Source:
DOE/Fermi National Accelerator Laboratory
Summary:
Scientists at Fermilab have found evidence of an unexpected particle whose curious characteristics may reveal new ways that quarks can combine to form matter.

The Tevatron typically produces about 10 million proton-antiproton collisions per second, sometimes creating particles known as B mesons. A B meson contains a quark-antiquark pair that includes either a bottom quark or anti-bottom quark. B mesons can decay directly into a J/Ψ (psi) particle and a Φ (phi) particle. The CDF scientists found evidence that some B mesons unexpectedly decay into an intermediate quark structure identified as a Y.
Credit: Image courtesy of DOE/Fermi National Accelerator Laboratory

Scientists of the Collider Detector at Fermilab (CDF) experiment at the Department of Energy's Fermi National Accelerator Laboratory announced that they have found evidence of an unexpected particle whose curious characteristics may reveal new ways that quarks can combine to form matter.

The CDF physicists have called the particle Y(4140), reflecting its measured mass of 4140 Mega-electron volts. Physicists did not predict its existence because Y(4140) appears to flout nature’s known rules for fitting quarks and antiquarks together.

“It must be trying to tell us something,” said CDF cospokesperson Jacobo Konigsberg of the University of Florida. “So far, we’re not sure what that is, but rest assured we’ll keep on listening.”

Matter as we know it comprises building blocks called quarks. Quarks fit together in various well-established ways to build other particles: mesons, made of a quark-antiquark pair, and baryons, made of three quarks. So far, it’s not clear exactly what Y(4140) is made of.

The Y(4140) particle decays into a pair of other particles, the J/psi and the phi, suggesting to physicists that it might be a composition of charm and anticharm quarks. However, the characteristics of this decay do not fit the conventional expectations for such a make-up. Other possible interpretations beyond a simple quark-antiquark structure are hybrid particles that also contain gluons, or even four-quark combinations.

The CDF scientists observed Y(4140) particles in the decay of a much more commonly produced particle containing a bottom quark, the B + meson. Sifting through trillions of proton-antiproton collisions from Fermilab’s Tevatron, CDF scientists identified a small sampling of B+ mesons that decayed in an unexpected pattern. Further analysis showed that the B+ mesons were decaying into Y(4140).

The Y(4140) particle is the newest member of a family of particles of similar unusual characteristics observed in the last several years by experimenters at Fermilab’s Tevatron as well as at KEK laboratory in Japan and at DOE’s SLAC National Accelerator Laboratory in California.

"We congratulate CDF on the first evidence for a new unexpected Y state that decays to J/psi and phi,” said Japanese physicist Masanori Yamauchi, a cospokesperson of KEK’s Belle experiment. “This state may be related to the Y(3940) state discovered by Belle and might be another example of an exotic hadron containing charm quarks. We will try to confirm this state in our own Belle data."

Theoretical physicists are trying to decode the true nature of these exotic combinations of quarks that fall outside our current understanding of mesons and baryons. Meanwhile experimentalists happily continue to search for more such particles.

“We’re building upon our knowledge piece by piece,” said CDF cospokesperson Rob Roser of Fermilab, “and with enough pieces, we’ll understand how this puzzle fits together.”

The Y(4140) observation is the subject of an article submitted by CDF to Physical Review Letters this week. Besides announcing Y(4140), the CDF experiment collaboration is presenting more than 40 new results at the Moriond Conference on Quantum Chromodynamics in Europe this week, including the discovery of electroweak top-quark production and a new limit on the Higgs boson, in concert with experimenters from Fermilab’s DZero collaboration. Both experiments are actively pursuing a very broad program of physics, including ever-more-precise measurements of the top and bottom quarks, W and Z bosons and searches for additional new particles and forces.

"Thanks to the remarkable performance of the Tevatron, we expect to greatly increase our data sample in the next couple of years, said Konigsberg. “We’ll study better what we’ve found and hopefully make more discoveries. It's a very exciting time here at Fermilab."


Story Source:

The above story is based on materials provided by DOE/Fermi National Accelerator Laboratory. Note: Materials may be edited for content and length.


Cite This Page:

DOE/Fermi National Accelerator Laboratory. "Particle Oddball Surprises Physicists." ScienceDaily. ScienceDaily, 19 March 2009. <www.sciencedaily.com/releases/2009/03/090318140618.htm>.
DOE/Fermi National Accelerator Laboratory. (2009, March 19). Particle Oddball Surprises Physicists. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2009/03/090318140618.htm
DOE/Fermi National Accelerator Laboratory. "Particle Oddball Surprises Physicists." ScienceDaily. www.sciencedaily.com/releases/2009/03/090318140618.htm (accessed July 30, 2014).

Share This




More Matter & Energy News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Britain Testing Driverless Cars on Roadways

Britain Testing Driverless Cars on Roadways

AP (July 30, 2014) British officials said on Wednesday that driverless cars will be tested on roads in as many as three cities in a trial program set to begin in January. Officials said the tests will last up to three years. (July 30) Video provided by AP
Powered by NewsLook.com
China's Drone King Says the Revolution Depends on Regulators

China's Drone King Says the Revolution Depends on Regulators

Reuters - Business Video Online (July 30, 2014) Comparing his current crop of drones to early personal computers, DJI founder Frank Wang says the industry is poised for a growth surge - assuming regulators in more markets clear it for takeoff. Jon Gordon reports. Video provided by Reuters
Powered by NewsLook.com
3Doodler Bring 3-D Printing to Your Hand

3Doodler Bring 3-D Printing to Your Hand

AP (July 30, 2014) 3-D printing is a cool technology, but it's not exactly a hands-on way to make things. Enter the 3Doodler: the pen that turns you into the 3-D printer. AP technology writer Peter Svensson takes a closer look. (July 30) Video provided by AP
Powered by NewsLook.com
Climate Change Could Cost Billions, According To White House

Climate Change Could Cost Billions, According To White House

Newsy (July 29, 2014) A report from the White House warns not curbing greenhouse gas emissions could cost the U.S. billions. Video provided by Newsy
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:
from the past week

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