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Fermilab Discovers Untheorized Particle 217

Posted by ScuttleMonkey
from the surprise-particles dept.
alevy writes to mention that scientists at Fermilab have detected a new, completely untheorized particle. Seems like Fermi has been a hotbed of activity lately with the discovery of a new single top quark and narrowing the gap twice on the Higgs Boson particle. "The Y(4140) particle is the newest member of a family of particles of similar unusual characteristics observed in the last several years by experimenters at Fermilab's Tevatron as well as at KEK and the SLAC lab, which operates at Stanford through a partnership with the U.S. Department of Energy. 'We congratulate CDF on the first evidence for a new unexpected Y state that decays to J/psi and phi,' said Japanese physicist Masanori Yamauchi, a KEK spokesperson. 'This state may be related to the Y(3940) state discovered by Belle and might be another example of an exotic hadron containing charm quarks. We will try to confirm this state in our own Belle data.'"
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Fermilab Discovers Untheorized Particle

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  • by Cyberax (705495) on Friday March 20, 2009 @03:28PM (#27273433)

    We _know_ that the current theory is insufficient. It doesn't explain gravity, for one thing.

    LHC will allow to test some alternative theories, so we really need it. Also, we still need to check the existance of Higgs.

  • Re:Thank goodness (Score:2, Informative)

    by amoeba1911 (978485) on Friday March 20, 2009 @03:47PM (#27273715) Homepage
    Jesus loves everyone*


    *everyone: excludes muslims, jews, atheists, protestants, people who work on sundays, gays, lesbians, people with aids, and people.
  • by SlashDotDotDot (1356809) on Friday March 20, 2009 @04:12PM (#27274035) Journal

    And that was in the 50s, so with the inflation, you can only guess how heavy the fine would be now.

    $88,046.89

    http://data.bls.gov/cgi-bin/cpicalc.pl?cost1=10000&year1=1950&year2=2009 [bls.gov]

    Just sayin.

  • by Zerth (26112) on Friday March 20, 2009 @04:12PM (#27274039)

    Photons don't slow, they redshift. You're probably thinking of the speed of light in non-vacuum.

  • by Anonymous Coward on Friday March 20, 2009 @07:32PM (#27275865)

    Tanakh, not Torah. The Torah plus the Prophets and the Writings were all completed before the birth of jesus.

  • by radtea (464814) on Friday March 20, 2009 @07:54PM (#27275953)

    This story *sounds* interesting to me as it appeals to my sense of exploration and curiosity to learn new things but beyond that this stuff basically reads like sub-atomic particle physics to me

    Here's my read on it: quarks are the constituents of a wide range of particles, from protons and neutrons to B-mesons etc. The fundamental interaction that holds these particles together is the "colour force" or "strong nuclear force", which arises due to the exchange of gluons between quarks in the same way that the electro-magnetic force arises because of the exchange of photons between charged particles.

    Virtual particle exchange is made possible by the uncertainty principle, which for a massless particle like the photon produces forces with infinite range, but for gluons, which have mass, it results in a short-range force. As well as mass, gluons also have "colour charge", so they interact with each other as well as with quarks, resulting in the confinement property of the strong force: if you try to pull two bound quarks apart, the gluons holding them together self-interact in a way that makes the force stronger rather than weaker. If you pull really hard you get new quarks popping out of the vacuum, and jets of exotic particles. You never get a naked quark.

    Computing the bound states of quarks is really, really hard because the force is so strong. The basic technique we use in quantum electro-dynamics is perturbation theory, where we get an approximate result and then apply a series of smaller and smaller corrections to it. Because of the self-interaction of the gluons, for quantum chromo-dynamics these corrections get larger and larger, and various other mathematical techniques have to used to get a well-behaved answer.

    This means that while we can predict pretty well the excited states of atoms, we can't do that for quarks. I would bet the most likely form of this particle is some kind of multi-quark object (more than just a simple pair) whose existence depends on the details of the colour force. We are still learning what those details are, and this particle and others like it will be useful laboratories to reveal them.

    So the significance of the discovery is that it provides us with a new way of studying quantum chromo-dynamic interactions. Not the world's biggest deal, but still very cool and useful.

  • by Doc Ri (900300) on Friday March 20, 2009 @10:00PM (#27276603)

    a) Combining quarks into hadrons in different ways leads to different properties of the resulting bound state. The mass is an obvious example. Unfortunately, while rather easily accessible experimentally, it is hard to predict the mass of bound states with high precision in QCD (the theory describing the strong force). Others properties can be more powerful here. For example the intrinsic angular momentum (spin) and the parity of the bound state. The decay product trajectories from particles with different spin/parity will show different angular distributions. By measuring these distributions one can rule out certain combinations.

    b) In general what would be required is someone working out in more detail how these predicted particles would interact with known particles, in this case charm and strange quarks. I just read through the article you linked to. According to the article, all predicted particles are gauge bosons, i.e. they introduce new interactions. The number in the name Y(4140) refers to the mass measured in MeV. A gauge boson with such a low mass coupling to quarks would have been noticed already. Furthermore, the reported observation does not hint anything exotic. Just something that is perfectly allowed in the Standard Model, although not fully understood in its dynamics yet. So I'm afraid, no, this is not a candidate for your favourite model.

     

  • by Ambitwistor (1041236) on Saturday March 21, 2009 @06:01PM (#27283157)

    I know people are puzzled by it, but once again, the Pioneer anomaly does not prove that "we don't understand gravity". We don't understand the Pioneer anomaly. Whether it has to do with gravity is another question.

Between infinite and short there is a big difference. -- G.H. Gonnet

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