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SELEX at Fermilab Discovers New Particle
sellthesedownfalls writes "Scientists at the Department of Energy's Fermi National Accelerator Laboratory will announce on Friday, June 18 the observation of an unexpected new member of a family of subatomic particles called 'heavy-light' mesons. The new meson, a combination of a strange quark and a charm antiquark, is the heaviest ever observed in this family, and it behaves in surprising ways -- it apparently breaks the rules on decaying into other particles. See the Fermilab Press Release."
It's a bound state of two quarks. The charm quark is "heavy", i.e. relatively massive, while the the strange quark is less so.
Victor Ninov at Lawerence Berkley National Laboratory.
Let's hope Fermilab is more certain about this discovery.
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IANAP either, but I think the idea is that these energies were seen when the universe was very young, so yet they are discoveries.
whether they are allowed in nature is more of the issue... in the sense chemical elements (well defined) cannot have arbitrary number of protons and neutrons. even for isotopes, they can't just have any combinations...
Actually, they do occur in nature. Specifically, they occur when a sufficiently energetic cosmic ray strikes our atmosphere.
This is the same reason that many physicists laugh off the idea that they're going to create a mini-black hole that would sink to the earth's core and destroy us all. The universe is constantly running even higher-energy experiments in our atmosphere all the time - we just haven't placed our detectors in the right place! (To be fair to our hard-working particle physicists, you would need a VERY large detector hovering high in the air if you wanted to catch these things in nature.)
Ben Hocking
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...it's a new discovery!
We certainly expected that there would be a strange-anticharm meson, but until it was observed, there was no way to tell it's mass (except in a very broad range of likely masses for members of the heavy-light mesons) and it's lifetime. Quantum chromodynamics, while in many respects a remarkably precise theory, still has to have the masses of the particles put into the equations. In a real Theory of Everything, we'd be able to calculate the mass of such a meson before we'd seen it.
These particles certainly exist in nature, but because their lifetime is so short, you'd have to be right where they were created to be able to see them before they decayed. Since our detector-on-the-surface-of-a-neutron-star project (affectionately called the DOTSOAN project) has had its funding denied again, the only place we can be observing right where they were created is right here on Earth in the accellerators.
Anomalous: deviating from what is usual, normal, or expected
Canard: a false or unfounded repor
http://www.fnal.gov/pub/presspass/press_releases/s elex_photos/index.html
The rules are just the way we understand things. When something breaks the rules, it means we need to put the rules back together so that they aren't broken as easily.
There's a difference between defying human theories of physics, and defying nature.
This is definitely "order of magnitude" a typical strong decay.
There are two things which are unusual about this, however:
1) It's a strong decay, and the particle is more massive than other exotic (with more than just down/up quarks) mesons, but this one lives longer than light mesons in its family. Whether this means it's longer lived than charm-down or charm-up mesons or longer lived than a lighter resonance of charm-strange isn't enunciated here, but either way, that's a surprise. There may be some type of parity conservation at work.
(NB - strong interactions conserve parity)
2) It decays into an eta particle much more often (6x more) than decay into a kaon. This is unusual, because more phase space is available for kaons (they have less mass than etas, therefore it's energetically favorable). Again, this could be related to parity issues, like pion decay (prefers muons over less-massive electrons), but that isn't enunciated here either.
It just goes to show that there's a lot left to investigate just in the basic standard model -- something that a lot of the SUSY/string-loving public forgets quite often. (IAAP, btw)
It's a wonder they got any work done that day...
:)
With 6800 acres of buffalo, trails, and lakes, not to mention a swimming pool, basketball and tennis courts, a rec center and bar (the alcoholic type) its a wonder we ever get any work done around here
Those fine folks who subscribe to my arXiv.org RSS feeds probably have already read the full paper:
http://arxiv.org/abs/hep-ex/0406045
My RSS feeds can be found at:
http://www.ucalgary.ca/~cmhogan/arXivRDF/
In any field, find the strangest thing and then explore it. -John Archibald Wheeler
The alleged story is indeed mostly true (reference here) although apparently it was two Heineken bottles, and the the theory of how they got there is that it was a prank, not an oversight during construction.
In Soviet Rush, today's Tom Sawyer gets high on you.
Oh- I thought there was a more general interpretation of Heisenberg available as well
You are falling into the trap of mistaking an interpretation of the theory, i.e. what people say about that theory ( such people often being clueless in the first place) for what the theory actually "says".
Much like people often claim that The Theory of Relativity "says" that everything is relative, which is completely wrong. The Theory of Relativity "says" that the speed of light is absolute.
KFG
It does no such thing. It proves that in a consistent logical system capable of describing arithemetic, there exist statements whose truth cannot be decided within the system. However, the laws of physics are only a very small subset of all possible statements that can be expressed within a formal system. Goedel's theorem doesn't say that every subset of statements is incomplete. It's easy to make a bunch of statements, all of which are provably true; just look at any math book. It's possible that the laws of physics consist of such a set. It's also possible that the laws of physics might contain undecidable statements, which can be neither proven nor disproven, but it doesn't follow from Goedel's theorem that they must contain such statements.
Or "forbidden" lines in atomic spectra...they only happen in a vacuum so tenuous that the atoms aren't bumping into each other and giving up energy before they radiate at the forbidden line. They got the name because they could not be seen in a laboratory vacuum. You need to look at nebulae to see them.
-aiabx
Just this guy, you know?
In my mind, I like to envision this guy (Victor Ninov, who presented fraudulent data on super-heavy atoms) strung up and shot for the damage he's done to the public perception of science. Somebody always brings this up when a discovery is announced.
Here at the CDF experiment (as well as for essentially all of the Fermilab collaborations), there exists a procedure generally known as the "blessing" of analyses, wherein one has to submit results in (multiple) meetings of collaborators who do overlapping work. Much sniping and nit-picking ensues, but the end result is typically a thorough internal peer-review process before an analysis can be made public. You would be quickly discovered here if you tried to just generate some data. Though I don't know how they do it at LBNL...
Anyway, I look forward to out meeting Monday where we'll review evidence for observation of this D_s state here.
(I Am A Lowly Grad. Student Physicist.)
Anecdotal evidence! I'm sold!