New particle turns up in Japan

Physicsweb ^ | Nov 14, 2003 | Belle Dumé

[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

[AndyJackson]

Is that a strange quark or an anti-charmed quark.

[JusPasenThru]

This is just the point I've been trying to make for a long time.

[Qwinn]

Ah. Yes, I was aware that there is a faith-based initiative program out there for a particle called the graviton. The memo I would have missed would have been the one where they said they found a shred of evidence for it.

"Although the graviton has not yet been observed, it is thought that there is an exchange particle associated with gravity and that eventually gravity will be described in a unified theory with the other three forces of nature".

Who says scientists don't have religion? ;)

Personally, I don't think there is such a thing as a graviton. Then again, I'm a heretic in several other ways as well.

Qwinn

[Alamo-Girl]

Thanks for the heads up!

[Lazamataz]

Is that a strange quark or an anti-charmed quark.

Looks like a bottom to me.

[Alamo-Girl]

Oops! My bad. The heads up was from PatrickHenry! Thanks, PH!

[Qwinn]

P.S. Sorry if that came off rude, I didn't mean to be. I think it's very cool that you posted all this stuff up. I was actually excited when I read that, as I thought I might have missed something (heck, discovering a graviton would be cool, it would make antigravity theoretically easier to implement).

Personally, I think gravity is caused by mass curving space-time. Yes, I realize that would probably involve thinking of "space-time" as having intrinsic properties outside of the perspective of matter or energy. I don't know how much people would accept that these days, but from my reading I never thought that the totally relativistic model of space-time was ever established. Indeed, gravity may be the -only- way to measure that existence. *shrug*

I'm just a layman, not a professional. But I've always been a hard sci-fi fan. Larry Niven was always one of my favorites. I don't have that much formal education in the hard sciences, but I've spent a whole lot of my time theorizing and dreaming about it, and have independently arrived at several conclusions that I later found out had been borne out by the facts, so I'll stick with my gut instincts for now :)

Qwinn

[VadeRetro]

Personally, I think gravity is caused by mass curving space-time.

This would still be true in the QM (graviton) model, so there is no conflict. (We know gravitational lensing happens. Any model that predicts otherwise has already been falsified.) Standing fields are regions of space wherein some property has been altered. In the case of gravity, it's the curvature of the space. For electricity and magnetism, the properties are called permittivity and permeability, respectively.

When an object generating a field is moved, it exchanges virtual particles (gravitons in one case, photons in the other two cases) with the surrounding space. That is how the space "knows" to change.

[Lazamataz]

Oops! My bad. The heads up was from PatrickHenry! Thanks, PH!

You still saying 'heads up' after that last drubbing? ;^)

[Lazamataz]

We know gravitational lensing happens.

Or perhaps it just appears to be happening.

[PatrickHenry]

You still saying 'heads up' after that last drubbing?

Would you have her say: "Thanks for the ping"?

[VadeRetro]

This would still be true in the QM (graviton) model ....

Probably should call that the QED (Quantum Electrodynamics) model.

[VadeRetro]

Would you have her say: "Thanks for the ping"?

Why not? I can think of few things nicer to hear back than, "Thank you for that ecstatically scintillating ping!"

[VadeRetro]

Or perhaps it just appears to be happening.

There's no proof it's not all some big cosmic prank, of course.

[Alamo-Girl]

LOLOL! I guess old habits are hard to break...

[Qwinn]

Interesting post. I haven't found much good hard sci-fi or non-fiction to read in the last decade or so, so my knowledge is lagging and I may ask stupid/obsolete questions.

Can you please define for me what is meant by gravitational lensing in the context you put it in?

Another question I have:

The last I'd heard, the big problem in the theoretical models of how electricity works was as follows. There are two logical models that make sense -

1) Electrons are passed from one molecule to the next along the conductive material - piggy-backing within the valence shell of one for an instant and being popped out the other side into the valence shell of the next atom. The electrons coming in on one side of the conductive wire are the same electrons that went in.

2) Electron pops in one side of the valence shell of an atom, which displaces a different electron on the other side.

My latest understanding is that -both- of these models had recently been discredited. It's also very difficult to think of a third alternative that makes any sense - heh. Anything I'm discussing here sound familiar?

Qwinn

[Qwinn]

Ack.

"The electrons coming in on one side of the conductive wire are the same electrons that went in come out on the other side."

Qwinn

[Alamo-Girl]

Luis Gonzales once posted an article about a beheaded man and was patiently awaiting my "thanks for the heads up!" - as I recall he had a come-back he wanted to use. But I caught myself and used a different phrase... LOL!

The one Lazamataz is speaking of had to do with sex. I missed that one so I got a much-deserved drubbing. LOL!

I like your suggestion, Vade, but I need something a bit shorter to type (I'm on a lot of ping lists.)

How about a simple, "Thanks!"???

[VadeRetro]

My latest understanding is that -both- of these models had recently been discredited.

News to me, but I hadn't been following that issue. In fact, I thought electricity was a pretty settled deal. Number one sounds the most like what I've heard.

[VadeRetro]

Can you please define for me what is meant by gravitational lensing in the context you put it in?

Didn't mean to forget this part. Many instances are known of light bending around massive objects. The first was Eddington's observation in a 1919 solar eclipse of an apparent shift in the position of a star near the sun, pretty much as predicted from Einstein's 1915 General Relativity. Since then, the Hubble in particular has taken some spectacular pictures of galaxies "lensing" the images of other galaxies behind them. It's well documented that mass distorts space.