Posted on 09/03/2008 12:54:20 PM PDT by decimon
Batavia, Ill. - Physicists of the DZero experiment at the U.S. Department of Energy's Fermi National Accelerator Laboratory have discovered a new particle made of three quarks, the Omega-sub-b (Ωb). The particle contains two strange quarks and a bottom quark (s-s-b). It is an exotic relative of the much more common proton and weighs about six times the proton mass.
The discovery of the doubly strange particle brings scientists a step closer to understanding exactly how quarks form matter and to completing the "periodic table of baryons." Baryons (derived from the Greek word "barys," meaning "heavy") are particles that contain three quarks, the basic building blocks of matter. The proton comprises two up quarks and a down quark (u-u-d).
Combing through almost 100 trillion collision events produced by the Tevatron particle collider at Fermilab, the DZero collaboration found 18 incidents in which the particles emerging from a proton-antiproton collision revealed the distinctive signature of the Omega-sub-b. Once produced, the Omega-sub-b travels about a millimeter before it disintegrates into lighter particles. Its decay, mediated by the weak force, occurs in about a trillionth of a second.
Theorists predicted the mass of the Omega-sub-b baryon to be in the range of 5.9 to 6.1 GeV/c2. The DZero collaboration measured its mass to be 6.165 ± 0.016 GeV/c2. The particle has the same electric charge as an electron and has spin J=1/2.
The Omega-sub-b is the latest and most exotic discovery of a new type of baryon containing a bottom quark at the Tevatron particle collider at Fermilab. Its discovery follows the observation of the Cascade-b-minus baryon (Ξb-), first observed by the DZero experiment in 2007, and two types of Sigma-sub-b baryons (Σb), discovered by the CDF experiment at Fermilab in 2006.
"The observation of the doubly strange b baryon is yet another triumph of the quark model," said DZero cospokesperson Dmitri Denisov, of Fermilab. "Our measurement of its mass, production and decay properties will help to better understand the strong force that binds quarks together."
According to the quark model, invented in 1961 by theorists Murray Gell-Mann and Yuval Ne'eman as well as George Zweig, the four quarks up, down, strange and bottom can be arranged to form 20 different spin-1/2 baryons. Scientists now have observed 13 of these combinations.
"The measurement of the mass of the Omega-sub-b provides a great test of computer calculations using lattice quantum chromodynamics," said Fermilab theorist Andreas Kronfeld. "The discovery of this particle is an example of all the wonderful results pouring out of accelerator laboratories over the past few years."
The Omega-sub-b is a relative of the famous and "even stranger" Omega-minus, which is made of three strange quarks (s-s-s).
"After the discovery of the Omega-minus, people started to accept that quarks really exist," said DZero co-spokesperson Darien Wood, of Northeastern University. "Its discovery, made with a bubble chamber at Brookhaven National Laboratory in 1964, is the textbook example of the predictive power of the quark model."
The DZero collaboration submitted a paper that summarizes the details of its discovery to the journal Physical Review Letters. It is available online at: http://www-d0.fnal.gov/Run2Physics/WWW/results/final/B/B08G/
DZero is an international experiment of about 600 physicists from 90 institutions in 18 countries. It is supported by the U.S. Department of Energy, the National Science Foundation and a number of international funding agencies. Fermilab is a national laboratory funded by the Office of Science of the U.S. Department of Energy, operated under contract by Fermi Research Alliance, LLC.
Bump for da' burbsssss.
Sounds like discovery of yet some more spin! LOL.
I believe we need an obligatory picture of the Ferengi bartender...
I really try to understand this partical physics stuff, but I have a hard time wrapping my brain around it.
Now, part of it is the nature of the subject, but I find a big part of it is the terminology used. I think some better descriptive terms for particals and their components might help make this study more accessible to laypeople.
Just MHO.
It's a fascinating place.
L
Not me. I just post this stuff for the weirdific factor. And because there could be a few here with a true interest.
From now on I dub the Omega-sub-b ------ TIM.
Lots of strangeness in San Francisco
That one? No... That one? Nope...
Soon they'll be scraping the bottom quarks.
Hmmm, Aldi grocery stores (cheap Aldi brand stuff) has its U.S. headquarters in Batavia, and now weird sub-atomic particles are found there. I wonder.
Is this Flubber?
Beat me to it. And here I thought I was so clever.
Sung to the tune of “Oh! Susanna, don’t you cry for me.”
“Oh, no Bama, please don’t lie to me... for I’m off to Free Republic with a keyboard on my knee.”
I come from Minnesota with my keyboard on my knee;
I’m goin’ to Free Republic my true love for to see.
It rained all night the day I left,
the weather it was dry;
The sun so hot I froze to death,
Obama don’t you lie.
Oh! No Bama, don’t you lie to me;
I come from Minnesota,
with my keyboard on my knee.
I had a dream the other night,
When everything was still;
I thought I saw Obama dear,
A-coming down the hill.
The smearing lie was in Duluth,
The tear was in his eye,
Said I, I’m coming for the truth
Obama don’t you lie.
Oh! No Bama, don’t you lie to me;
I’m off to Free Republic,
with my keyboard on my knee.
I fight in my pajamas
It’s plain for all to see
I aim to be the next Buckhead
The media all hate me.
I fell in love with Sarah
When my sister bit a moose
The Guvnor’s family ate it up
And then they set it loose.
Oh! No Bama, don’t you lie to me;
I’m off to Free Republic,
with my keyboard on my knee.
I soon will be in Hawaii,
And then I’ll look all ‘round,
And when I find his birth record,
I’ll fall upon the ground.
But if I do not find it,
This Freeper’ll surely die,
And when I’m dead and buried,
Obama don’t you lie.
Oh! No Bama, don’t you cry for me;
I’m off to Free Republic with a keyboard on my knee
http://www.freerepublic.com/focus/chat/2073903/posts?page=6#6
And dude-ettes.
Cheers!
(Sorry I left you off the earlier list -- I've got Palin on the brain).
Cheers!
Yes, there are FReepers with a true interest, even if most of us will never contribute meaningfully to particle physics on either the experimental or theoretical sides.
Chrisser, some of the properties of particles are analogs for things in everyday life. For example, up/down and spin. Others of the properties are just whimsical names like strangeness. These descriptors serve to categorized the particles into natural groups.
Baryons and mesons are types of particles that are composed of these tiny indivisible (as far as we know) particles called quarks. Most baryons are composed of three quarks. Baryons and mesons together are called hadrons. The LHC, or Large Hadron Collider, is expected to reveal considerable information about these particles.
Combing through almost 100 trillion collision events produced by the Tevatron particle collider at Fermilab, the DZero collaboration found 18 incidents in which the particles emerging from a proton-antiproton collision revealed the distinctive signature of the Omega-sub-b. Once produced, the Omega-sub-b travels about a millimeter before it disintegrates into lighter particles. Its decay, mediated by the weak force, occurs in about a trillionth of a second.Yeah, sure, okay. ;')
thanks, bfl
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.
