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Physicists find 'rebel' particle
BBC ^ | 30 April, 2003, 11:16 GMT 12:16 UK | By Dr David Whitehouse

Posted on 04/30/2003 1:05:30 PM PDT by alnitak

Physicists find 'rebel' particle

By Dr David Whitehouse


BBC News Online science editor


Physicists have found a new subatomic particle, named Ds (2317). It will help them better understand the building blocks of matter.

BaBar detector, Slac
Inside the BaBar detector

The particle consists of an unusual combination of more fundamental particles - quarks.

Two quarks form Ds (2317) and, curiously, its properties are not what theory predicted.

The announcement was made by physicist Antimo Palano to a packed auditorium at the Stanford Linear Accelerator Center (Slac) in the US.

The discovery was made by the BaBar international consortium, which operates a detector at Slac that analyses debris from subatomic particle collisions.

'Back to the drawing boards'

"Congratulations to BaBar," said Slac's director, Jonathan Dorfan.

"The existence of the particle is not a surprise, but its mass is lower than expected. This result will send theorists back to their drawing boards."

BaBar data, Slac
The peak in the data betrays the new particle's existence

Quarks are fundamental particles of which there are six types present in nature. The "up" and "down" quarks are the lightest, and are found within the nuclei of atoms of ordinary matter.

There are also the "charm", "strange", as well as the "top" and "bottom" quarks. These are heavier than the up and down quarks. Quarks can also have antiparticles such as anti-down, etc.

Heavier quarks were present in the early Universe and are created today in particle accelerators and in collisions of cosmic rays with atoms in the Earth's atmosphere.

The Ds (2317) combines a charm quark with another heavy quark - an anti-strange quark.

'From unexpected directions'

Physicists are hailing its discovery as important because it has unexpected properties that will provide insight into the force that binds the quarks together.

This force, unlike most others in nature, becomes stronger as the distance between the two quarks increases.

Marcello Giorgi, from the University of Pisa, Italy, who leads the BaBar collaboration, said: "Sometimes, the most exciting discoveries come from unexpected directions. There has been a buzz of excitement in the experiment in the past few weeks.

Slac aerial, Slac
Slac fires particles along a track

"We have discovered a new charm particle in an experiment designed to probe the difference between matter and antimatter using bottom quarks."

Bob Cahn, a BaBar collaborator from Lawrence Berkeley National Laboratory, US, added: "The unexpected mass will make us look again at the forces between quarks and will stimulate new interest in charm-quark systems."

And Dr Raymond Orbach, director of the US Energy Department's Office of Science, said: "The BaBar experiment continues to produce important new knowledge adding to our fundamental understanding of the structure of matter."



TOPICS: Miscellaneous; News/Current Events
KEYWORDS: particle; physics; realscience; science; stanford
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To: techcor
Now what about those Tachyon particles....
21 posted on 04/30/2003 2:29:39 PM PDT by ffusco (Maecelius Fuscus, Governor of Longovicium, Britannia (Manchester, England. AD 238- AD 244))
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To: ffusco
Because they are FTL they are traveling back in time. If you can't remember seeing them by now, you probably never will.
22 posted on 04/30/2003 2:33:42 PM PDT by techcor (Admin Moderator wannabe)
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To: techcor
Why was Woody Boyd's middle name Tiberius?
23 posted on 04/30/2003 2:42:55 PM PDT by ffusco (Maecelius Fuscus, Governor of Longovicium , (Manchester, England. 238-244 AD))
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To: Doctor Stochastic
Isn't there a children's book called "BaBar"?

You mean this guy?


24 posted on 04/30/2003 3:04:07 PM PDT by Physicist
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To: Physicist
The article says this:
This force [that binds the quarks together], unlike most others in nature, becomes stronger as the distance between the two quarks increases.

It's not surprising that I'm not up to date in this exotic field, but I didn't expect to be totally blindsided by something. How long has this been going on? I assume this is the reason that no free quarks exist in nature. Still, it's a darn curious thing.

25 posted on 04/30/2003 4:00:04 PM PDT by PatrickHenry (Felix, qui potuit rerum cognoscere causas.)
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To: alnitak
read later
26 posted on 04/30/2003 4:25:18 PM PDT by LiteKeeper
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To: alnitak
read later
27 posted on 04/30/2003 4:27:04 PM PDT by LiteKeeper
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To: PatrickHenry
It's not surprising that I'm not up to date in this exotic field, but I didn't expect to be totally blindsided by something. How long has this been going on?

Since the universe was 10-5 seconds old, when the hadrons formed. ;^)

The theory was worked out in the 1960's. The key features of QCD are confinement and asymptotic freedom. Confinement means that the quarks are confined to hadrons, as you mentioned. Asymptotic freedom means that as the quarks get closer and closer together, the strong-force interaction between them asymptotically approaches zero, i.e. they behave as free particles as far as the strong force is concerned. (They still interact electromagnetically, etc.)

Both of these features are exhibited by a force that is directly proportional to distance. Asymptotic freedom is obvious--the force goes to zero at zero distance--but confinement is less obvious. That arises from the fact that the quarks have finite masses. If the force is proportional to distance, you can only pull a quark and an antiquark so far apart before you put in enough energy to pry a new quark-antiquark pair out of the vacuum. The color charges cancel those of the quarks you're pulling apart, and they "hadronize": the new quark pairs up with the old antiquark, the new antiquark pairs up with the quark, and you have two "colorless" mesons instead of two quarks.

The usual pedagogical analogy is to try to obtain monopoles by pulling a bar magnet apart. It just won't work.

28 posted on 04/30/2003 4:42:11 PM PDT by Physicist
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To: techcor
The Warp Speed of the Enterprise is adjusted so it takes exactly one week minus an hour to get to the next episode destination on time.
29 posted on 04/30/2003 4:48:56 PM PDT by RightWhale (Theorems link concepts; proofs establish links)
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To: PatrickHenry
This force [that binds the quarks together], unlike most others in nature, becomes stronger as the distance between the two quarks increases.

And these scientists don't have teenage kids?

Scientists discover "Rebel" particle.

Has anyone told the NAACP yet?
30 posted on 04/30/2003 4:53:08 PM PDT by tet68 (Jeremiah 51:24 ..."..Before your eyes I will repay Babylon for all the wrong they have done in Zion")
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To: *RealScience; Ernest_at_the_Beach
http://www.freerepublic.com/perl/bump-list
31 posted on 04/30/2003 6:28:52 PM PDT by Libertarianize the GOP (Ideas have consequences)
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To: Physicist
The usual pedagogical analogy is to try to obtain monopoles by pulling a bar magnet apart. It just won't work.

Maybe the Teamsters were doing a preemptive strike in anticipation of this thread. ;^)

32 posted on 04/30/2003 6:32:27 PM PDT by ArneFufkin
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To: alnitak
Quarks are fundamental particles of which there are six There are also the "charm", "strange", as well as the "top" and "bottom" quarks. These are heavier than the up and down quarks. Quarks can also have antiparticles such as anti-down, etc.

They are faculty PHD's in Subatomic Physics and also scriptwriters for "Barney's Playhouse"

33 posted on 04/30/2003 6:39:08 PM PDT by ArneFufkin
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To: Physicist
And there's no Top Quark. Quarks exist in an autonomous hadronic collective.
34 posted on 04/30/2003 8:21:38 PM PDT by Doctor Stochastic (Vegetabilisch = chaotisch is der Charakter der Modernen. - Friedrich Schlegel)
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To: Doctor Stochastic
You're fooling yourself. We're living in a spontaneously broken mass hierarchy.
35 posted on 05/01/2003 4:31:27 AM PDT by Physicist
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To: alnitak
Ping to read after coffee!!!
36 posted on 05/01/2003 4:39:47 AM PDT by Eaker (64,999,987 firearm owners killed no one yesterday. Somehow, it didn't make the news.)
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To: ffusco
Because "Tiberius" was the "T." in "James T. Kirk"?
37 posted on 05/01/2003 6:09:43 AM PDT by techcor (Admin Moderator wannabe)
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To: RightWhale
Unless it was "season finale" in which case the ship traveled 3months minus two hours. Talk about time warps. Talk about time warps.
38 posted on 05/01/2003 6:11:28 AM PDT by techcor (Admin Moderator wannabe)
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To: Physicist
Do the masses obtain by willfully breaking the symmetries?
39 posted on 05/01/2003 6:20:36 AM PDT by Doctor Stochastic (Vegetabilisch = chaotisch is der Charakter der Modernen. - Friedrich Schlegel)
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To: Physicist; PatrickHenry
***How long has this been going on? ****

Since the universe was 10-5 seconds old, when the hadrons formed. ;^) ========================================================

Well, if you can't be any more specific than that....

</sarcasm mode>

Your reply to PH was simply delightful; succinct and chock-full of fascinating info.

40 posted on 05/01/2003 10:23:54 AM PDT by longshadow
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