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New particle turns up in Japan
Physicsweb ^ | Nov 14, 2003 | Belle Dumé

Posted on 11/15/2003 8:43:52 PM PST by Diddley

The Belle collaboration at the KEK laboratory in Japan has discovered a new sub-atomic particle which it is calling the "X(3872)". The particle does not fit into any known particle scheme and theorists are speculating that it might be a hitherto unseen type of meson that contains four quarks (arxiv.org/abs/hep-ex/0309032; Phys. Rev. Lett. to be published).

The discovery has been confirmed by the CDF collaboration at Fermilab in the US, where the new particle is being called the "mystery meson". Mesons are particles that contain a quark and an antiquark that are held together by the strong nuclear force.

Since there are six different "flavours" of quark - up, down, strange, charm, bottom and top - it is possible to form a large number of different mesons.

The Belle team measured the decay of B-mesons - mesons that contain a bottom quark - produced in electron-positron collisions at the KEK B-factory in Japan. The team plotted the number of candidate events for B mesons against mass and observed a significant spike in the distribution at 0.775 GeV. This corresponds to a mass of nearly 3872 MeV. The particle decayed almost immediately into other, longer lived particles.

The KEK team says that the mass of this new meson is higher than theoretical predictions. Moreover, the way in which it decays also differs from theory. One possibility is that current models of the strong force need to be modified. Alternatively it could be that X(3872) is the first example of a "molecular state" meson that contains two quarks and two antiquarks.

Until recently particle physicists had only ever detected particles that contain two or three quarks. However, in the past year evidence has emerged for another four-quark particle known as the Ds(2317) and a five-quark particle known as the pentaquark.

Author Belle Dumé is Science Writer at PhysicsWeb


TOPICS: Japan; Technical
KEYWORDS: crevolist; japanparticle; meson; neutrino; neutrinodetector; neutrinos; newpalticurr; physics; quantumparticle; quark; science; stringtheory; subatomicparticle
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To: P.O.E.
WHAT...the HELL...is......THAT?????????????????
141 posted on 11/16/2003 10:23:35 PM PST by Capitalism2003 (Come on Freepers! http://www.NRSC.org)
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To: William Tell
Has anyone made a bucky ball out of silicon yet?

Yes (there are probably better examples):

http://prola.aps.org/abstract/PRL/v74/i8/p1427_1

Superconductivity in the Silicon Clathrate Compound (Na,Ba) xSi46
Hitoshi Kawaji, Hiro-omi Horie, Shoji Yamanaka, and Mitsuo Ishikawa

Department of Applied Chemistry, Faculty of Engineering, Hiroshima University, Higashi-Hiroshima 724, Japan

Received 8 August 1994

A new silicon clathrate compound containing barium, (Na,Ba) xSi46, becomes a type-II superconductor with a critical temperature (Tc) of about 4 K. In the compound, the silicon atoms are bonded tetrahedrally with about the same bond distances as in ordinary cubic diamond Si, but form 12- and 14-hedral cages which are linked by shared faces. The metal atoms are located in the center of the polyhedra. This is the first superconductor consisting of a Si sp3 covalent network.
142 posted on 11/17/2003 12:52:41 AM PST by AdmSmith
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To: William Tell
Please excuse my ignorance, but are you saying that, for example the strong force, it is the transfer of particles within the atom that holds the atom together? If these particles are being exchanged, is there not still a "force" involved? With your example of the two men on the ice, they were still using "energy" to throw the balls (particles). What is the manifistation of this "energy" for subatomic particles?
Thanks!
Doug
143 posted on 11/17/2003 5:21:34 AM PST by Merdoug
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To: PatrickHenry
particle-like placemarker
144 posted on 11/17/2003 7:41:55 AM PST by longshadow
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To: longshadow
Charmed, I'm sure.
145 posted on 11/17/2003 8:03:38 AM PST by PatrickHenry (Felix, qui potuit rerum cognoscere causas.)
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To: William Tell
I don't think GR messes up the point source with sphere, but I haven't checked carefully. With two point sources moving relative to each other, GR does predict gravitational waves but I don't think Newton does.
146 posted on 11/17/2003 8:09:16 AM PST by Doctor Stochastic (Vegetabilisch = chaotisch is der Charakter der Modernen. - Friedrich Schlegel)
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To: Merdoug
Merdoug asks: ..."are you saying that, for example the strong force, it is the transfer of particles within the atom that holds the atom together? If these particles are being exchanged, is there not still a "force" involved? With your example of the two men on the ice, they were still using "energy" to throw the balls (particles). What is the manifistation of this "energy" for subatomic particles?

First a disclaimer. I can handle the men on platforms throwing a ball. The physics of nuclear forces is a topic with which I have a very dated, limited exposure.

The way I would answer your question is that "force" is simply the description we give to describe when things are interacting. If one particle moves toward another and the second particle changes its behavior, then we describe the second particle as having been "forced" to change its behavior. The laws of physics describe in detail how the behavior will change.

In common usage, the word "force" tends to imply that a person could sense pressure or pain or some other manifestation of one object interacting with another. Physiologically, these sensations are just our own bodies or senses being interacted with and changing their behavior due to some other object.

The detailed behavior of the universe, whether we like it or not and whether it appeals to our intuition, is that "forces" in the physical world require time to elapse before the cause can create the effect.

A flare on the surface of the sun cannot be sensed on earth until about eight minutes after the event happens on the sun. Any effect on the earth is due to "radiation", either electromagnetic or particles, reaching the earth. ( The particles taking much longer than the electromagnetic radiation.)

The electromagnetic radiation will arrive at the earth in the form of what we call "light". Experiments have shown that light is "quantized"; that is, any photon of a given frequency carries a specific amount of energy.

One of Einstein's contributions was the understanding of the photo-electric effect. Shining a light on a piece of metal reveals that the energy of each emiitted electron from the metal is a function of the frequency of the light and not the intensity of the light. The experiment is consistent with the understanding that the light consists of "photons" each of which is capable of causing the emission of a single electron. Thus, any force caused by the distant movement of electrically charged particles can be demonstrated to have effect through the actions of photons moving at the speed of light from the source of the energy to its recipient.

The nuclear force is theorized to operate similarly. Interaction between particles which exhibit the strong force do so by exchanging particles to convey energy and momentum.

The "graviton" is the presumed particle which plays the role of conveying energy and momentum from one mass interacting with some other mass through the gravitational force. The force of gravity is much, much weaker than the other forces and efforts to detect gravitons have not yet been successful (last I heard).

In summary, the answer to the question would be "yes", all forces involve the exchange of particles. At the finest level, everything which causes "free space" not to be empty seems to have a description which involves both wave and particle properties. The interactions between them are what constitute the activity in our universe.

147 posted on 11/17/2003 11:07:47 AM PST by William Tell
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To: William Tell
Experiments have shown that light is "quantized"; that is, any photon of a given frequency carries a specific amount of energy.

So THAT'S why my lamps are marked 'Hi Med and Lo' ...

148 posted on 11/17/2003 11:53:30 AM PST by _Jim ( <--- Rush speaks on gutless 'Liberalism' (RealAudio files))
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To: William Tell
Your response reminds me of a theory which I have come up with on the universe: To me, everything that has happened since the beginning of the universe is motion. After the first particles came into existance, it is simply a matter of their motion and how they interact with each other. Even the illusion of our thought process (chemicals in the brain causing responses to outside stimuli detected by our senses) ould be calculated mathmatically. I believe that, if we knew where the first partilces were, along with which direction they were going, we could predict the entire history of the universe (given that we had a compuer which could track every particle in the universe). It would be just an extension of a basic physics' formula: if you know an object and it's trajectory, you can calulate where it will be in the future.
149 posted on 11/17/2003 3:46:53 PM PST by Merdoug
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To: Merdoug
I believe that, if we knew where the first partilces were, along with which direction they were going, we could predict the entire history of the universe (given that we had a compuer which could track every particle in the universe). It would be just an extension of a basic physics' formula: if you know an object and it's trajectory, you can calulate where it will be in the future.

That was Laplace's idea about 200 years ago, but it has since been shown to be wrong.

For one thing, a deterministic universe is its own 'simplest computer'. In order to calculate the trajectories in the manner you suggest, it would take an amount of computing power that would grow exponentially in time. Any finite computer would be overwhelmed in a finite time.

For another thing, you can't number the photons. Fundamental charged particle interactions suffer what's called an "infrared divergence", which means that the number of photons radiated in the course of the interaction depends on then energy cutoff at which you stop counting. If you take the cutoff all the way down to zero, the number of real photons emitted goes to infinity. No matter where you place the cutoff, you'll be missing something, so your calculation will necessarily be imperfect.

[Geek alert: if you think that this infinite sum of photons will lead to infinite quantities, you're right...but that's only half of the story. The interaction also gets a contribution from the virtual photons, and this contribution to the calculation is also infinite. However, it has an opposite sign from the real contribution, and the two infinite sums almost exactly cancel. The remaining residue, as it turns out, is independent of where you place the cutoff. That said, the real contribution really is real, so you really can't count--or account for--all of the photons.]

Finally, and worst of all, many quantum events (such as subatomic decays) are uncaused, and cannot be accounted for by any mechanism involving particles in motion. If such an accounting were possible, then all ensembles of such events would necessarily obey an esoteric relation called Bell's Inequality. It is a fact of nature, however, that many real-world interactions violate Bell's Inequality. If you're interested, I wrote a brief sketch of Bell's Inequality (in the form of a Platonic dialogue) which may be found here.

150 posted on 11/17/2003 4:55:12 PM PST by Physicist
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To: freedomcrusader
Oh, and why should a hadron-anti-hadron pair (that is, quark-anti-quark pair) ultimately decay into three leptons?

Point of terminology: quarks aren't hadrons. Hadrons are particles composed of quarks.

For example, the pi+ decays first into a muon+ and a neutrino, then the muon decays into a positron (anti-electron) and an anti-neutrino?

A mu+ decays into a positron, an electron neutrino, and a muon anti-neutrino.

Hadrons decaying into leptons is thoroughly confusing to me, and implies that the former are composed of the latter somehow.

Well, no. Notice that in the pion decay you mentioned, an anti-muon and a muon neutrino were created. What happened was that when the pion decayed, the quark and antiquark--which were of different flavors, an up quark and an anti-down quark--annihilated into a virtual W+ boson. The W+ boson then "decayed" (manifested itself, really) in the form of a mu+ (i.e., an anti-muon) and a muon neutrino. One of these particles (the neutrino) carried one unit of "muon-ness", while the other (the mu+) carried negative one units of "muon-ness". The total muon-ness of the system was zero both before and after the pion decay.

It's the same deal with the decay of the mu+. The anti-muon-ness is conserved when it decays into the form of a muon anti-neutrino. It also emits a (virtual) W+ which instantly decays into a positron and an electron neutrino.

The conversion of a W+ into a positron and an electron neutrino (or a mu+ and a muon neutrino) is directly analogous to a high energy photon (i.e., a gamma ray) converting into an electron positron pair. The photon doesn't "contain" an electron and a positron prior to the conversion. Rather, at some point in time, the photon just connects to a single conserved electron current, doing a U-turn in time.

151 posted on 11/17/2003 5:17:50 PM PST by Physicist
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To: freedomcrusader
There's a heck of a lot more than 6. There are 6 quarks, 6 leptons (electron, muon, tau plus their respective neutrinos), photon, gluon, graviton, the W boson, and last but not least, the Z boson. I count 17, plus most if not all have a corresponding anti-particle, for upwards of 34. Did I miss any?

There are six quarks and six leptons. Of the gauge bosons, there is one photon, one Z, one graviton, a W+ and a W-, eight different gluons, and at least one Higgs (but there may be several). There is a Higgs-like particle in QCD called the pseudoscalar axion, but not everyone believes this will be manifest as a physical particle.

You might also count the anti-particles of the quarks and leptons, if you like, but the gauge bosons are their own anti-particles (save for the W+ and W-, which complement each other, and the eight gluons, ditto).

It is possible that neutrinos are also their own anti-particles. This was the formulation of Ettore Majorana, as opposed to the Dirac formulation which has both neutrinos and anti-neutrinos. If neutrinos were massless, as was thought until recently, then the two formulations would be mathematically equivalent. It turns out that neutrinos have nonzero masses, however, so someday we will know which formulation is correct.

So how many different fundamental particles are there? It depends how you count them. The string theorists will tell you there's just one.

152 posted on 11/17/2003 5:41:21 PM PST by Physicist
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To: Physicist
And thought the Doctor Seuss thing about what happens when a packet hits a socket was tough...
153 posted on 11/17/2003 5:42:35 PM PST by Poohbah ("Would you mind not shooting at the thermonuclear weapons?" -- Major Vic Deakins, USAF)
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To: Physicist
So I'm only 200 years behind; huh? :)
Obviously a computer capable of tracking the total number of subatomic particles in the universe would be immense, but the total number of particles is finite; isn't it? Your "proton counting stuff; is that a result of an observer changing what he is observing? If that's the case, then if one uses only mathematics and doesn't actally try to measure anything, then he wouldn't affect it, would he? And even if he did, WHICHEVER number that he chose would be the correct one, since my theory means that there is only ONE future path, and no matter what we do, we can only make the one decision: any idea of choice is an illusion. The future is already laid out and we can't change it; no matter what we do.
The subatomic decay with no apparent cause really messes up my "motion" theory, however. My theory depends upon one interaction causing the next. Spontanious events won't fit in.
154 posted on 11/17/2003 5:47:45 PM PST by Merdoug
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To: Merdoug
Obviously a computer capable of tracking the total number of subatomic particles in the universe would be immense, but the total number of particles is finite; isn't it?

It doesn't matter. The size of the calculation still grows exponentially with time. Pick a computer of any size you want. Eventually it will fall behind.

Your "[photon] counting stuff; is that a result of an observer changing what he is observing? If that's the case, then if one uses only mathematics and doesn't actally try to measure anything, then he wouldn't affect it, would he?

No, that's not what I'm talking about at all. I'm assuming Cartesian non-interfering omniscience (bunkum as that may be). My point is that there's no finite numbering scheme that you can use as the basis of grinding out your calculations. You ultimately have to pick some point at which you say, "I'm not including the rest of these photons in my calculations." And because you have to exclude some particles from your calculation, your answer can't really be exactly right.

And even if he did, WHICHEVER number that he chose would be the correct one, since my theory means that there is only ONE future path, and no matter what we do, we can only make the one decision: any idea of choice is an illusion.

How do you define "choice"?

155 posted on 11/17/2003 6:04:15 PM PST by Physicist
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To: Merdoug
Merdoug said: The subatomic decay with no apparent cause really messes up my "motion" theory, however.

It's probably even worse than you think.

Every particle in the universe exhibits both particle and wave behavior. The wave describing a particular particle is a function of space, describing the location of the particle, and time, describing the motion of the particle.

The value of the wave equation at any point in space relates to the probability of observing the particle at that position . Some positions will be more probable than others. But any position where the wave equation has a non-zero value represents a position where the particle might be found.

Einstein was very troubled by this aspect of quantum physics. He said "God does not play dice" with the universe. Einstein thought that it might be possible to know the value of some hidden variables that would then allow one to eliminate the uncertainty which is represented by the wave equations. Recent experiments support the idea that there are no hidden variables. The observed position of a particular particle is unknowable until after the observation is made.

This means that your computer program would be picking a value to use for the outcome of an interaction from all the possible values provided by the wave equation. There is no way that the computer is going to "pick" the same value that the actual universe "picks". This uncertainty would apply to every particle and every interaction.

156 posted on 11/17/2003 6:38:01 PM PST by William Tell
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To: Physicist
Please keep in mind that I have very little knowledge of physics, so be gentle. :)
When you tell me about computer limitations or "counting of proton" limitations; I understand. This is from a "god's eye view" of what is possible. All I'm saying is that MAYBE" it might be possible to do such a vast calculation in the future.
As to "choice"; let's say that I can go to work tomorrow or not go to work. I make a decison whether to go or not. What I'm saying is that the choice has ALREADY been made; it was made as soon as the universe began. I may THINK that I have freewill, but my genetics, my memories; everything that has happened to me throughout my life will cause me to make the choice that is "predestined" to occur; at a chemical level. It is all one particle hitting another hitting another. I get input from the enviroment and, based upon what I've already explained, I will react in only one way. If the guy is counting protons, whatever number he comes up with will be the number it is correct for the one path to continue.
157 posted on 11/17/2003 6:45:43 PM PST by Merdoug
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To: Merdoug
All I'm saying is that MAYBE" it might be possible to do such a vast calculation in the future.

And all I'm saying is that, even in a perfectly deterministic universe, such calculations are intractable in principle. (Moreover, not all perfectly deterministic systems are computable, but that's another can of worms.)

As to "choice"; let's say that I can go to work tomorrow or not go to work. I make a decison whether to go or not. What I'm saying is that the choice has ALREADY been made; it was made as soon as the universe began.

I don't see the philosophical difference, as long as I am my own simplest computer, because ultimately, nothing can predict me. Besides, if someone handed me a printout proving to me that all of my actions for the last three years were algorithmically predictable, it wouldn't change how I act or how I feel about myself.

Viewed a different way, if someone proved to me that many of my actions were instead decided by a truly random and unpredictable "Pop-a-Matic" in my brain, I wouldn't consider myself to be any more or less "in control" than if the "Pop-a-Matic" were exactly predictable. My decisions are, in large measure, a mystery to me in either case.

I may THINK that I have freewill,

That's as may be, but speaking for myself, I know I have freewill. That's because I define "freewill" as the process by which I make conscious decisions. Whether that's deterministic or random or something else, I can't tell you...but I suspect that it doesn't make any qualitative difference. You might be interested in my contributions to this thread.

If the guy is counting protons, whatever number he comes up with will be the number it is correct for the one path to continue.

You're still missing that point. Let me try one last time: whatever number he comes up with will be WRONG for the calculation to reflect the actual physics. Let "the path" go wherever it is destined; it will be as unpredictable as if it were random at some level. If a system's destiny is inscrutably hidden and unknowable in principle, can it really be called destiny?

158 posted on 11/17/2003 8:15:14 PM PST by Physicist
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To: GOPJ
[121]
Ping me when someone finds a gravitron.

:-)

159 posted on 11/17/2003 8:50:46 PM PST by Diddley (Hey LIbs: If you have a good story, why lie?)
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To: Physicist; Merdoug; William Tell; freedomcrusader; js1138; Doctor Stochastic; GOPJ; Qwinn; ...
and, to others.

I consider myself to be a well-informed layman in science, but the talent demonstrated here is astounding.

I have learned much.

Thank you.
160 posted on 11/17/2003 9:12:15 PM PST by Diddley (Hey LIbs: If you have a good story, why lie?)
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