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Mesons Flip Between Matter and Antimatter 150

steve writes "A team of over 700 physicists at Fermilab's Tevatron accelerator have observed the B-sub-s meson oscillating between matter and antimatter states at 3 trillion times a second. From the Fermilab press release: 'Immediately after the Big Bang some 13 billion years ago, equal amounts of matter and antimatter formed. Much of it quickly acted to annihilate the other, but for little-understood reasons, a bit more matter than antimatter survived, providing the universe with the planets, stars and galaxies visible today.' The Standard Model predicted the oscillation, and Fermilab has been working for 19 years to confirm it. The announcement is good press for Fermilab, which is pushing Congress to build a new 18-mile-long International Linear Collider."
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Mesons Flip Between Matter and Antimatter

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  • Re:Only a bit (Score:4, Informative)

    by Stranger4U ( 153613 ) on Thursday September 28, 2006 @04:56PM (#16236773)
    If I remember correctly from my astrophysics days, for every 8 billion anti-matter particles in the early universe, there were 8 billion and one matter particles. I would say an excess of 1 per 8 billion is "just a bit."
  • by trip11 ( 160832 ) * on Thursday September 28, 2006 @04:57PM (#16236795) Homepage
    Working as a physicist on the 'one in Geneva', there are a few answers to your question.

    First bigger is better. Although we haven't even turned on the LHC (large hadron collider)it isn't hard to imagine that at some point down the road we will reach the limit of what we can easily study here (much like fermilab is now). Do you realize just how long it actually takes to design, build, and get one of these things running? Decades really. And that isn't to mention the time spent just trying to lobby for funding. In effect we need to start now if we don't want to spend 5 years sitting on our asses waiting for construction. And you don't really want 5000 physicist, bored and with nothing to do?

    Secondly, the LHC is a ring collider. This means that it has a large circle that it accelerates the particles in. While this has some advantages in that it is easier to run at high energies, there are disadvantages as well. One of the larger problems is polarization of the incoming particles. Basicly spinning particles in a circle randomizes the spin direction which makes it very hard to study. There are some clever tricks to get around this (Check out 'spin flippers' at RHIC) but a linear collider can study this much more precisely.

    Another reason for a new collider is that it will collide different particles. Leptons not Hadrons for you physics geeks out there. Again the idea is that it will be harder to achive the same energy but the results will have much less error (roughly speaking). The idea of the NLC (next linear collider) is to be able to study in much more detail some very subtle effects that will be lost in noise at the LHC. And by noise I don't mean noise due to poor construction, but noise due to quantum mechanics.

    A last reason to build the NLC in the US and not Geneva is that all of us American's are flocking to Geneva (Yes I'm one of them). We jokingly call CERN the american brain drain. It would be good for american science as a whole I do belive to employ more of us locally.

    Arg, but it is late here and if I made any serious physics errors reguarding the LHC or NLC I appologize. Also this is a very hand waving sort of argument, very light on the details, take it as such.

  • by maxwell demon ( 590494 ) on Thursday September 28, 2006 @05:34PM (#16237391) Journal
    Isn't matter and energy the same thing?

    No. Matter is, well, matter (i.e. electrons, protons, etc.). Energy is a property of matter/fields.

    E=m*c^2?

    The m here is "mass", not "matter". Again, mass is a property of matter.
    BTW, this equation holds only for matter at rest; generally it's E^2 = (mc^2)^2 + (pc)^2.

    So shouldn't energy have turned back into matter at some point?

    Normally matter and antimatter are produced in equal amounts. Note that antimatter has positive energy (and positive mass) as well.
  • Re:Oh! Shiny! (Score:5, Informative)

    by wass ( 72082 ) on Thursday September 28, 2006 @07:07PM (#16238669)
    I'm a doctoral student in physics (experimental condensed matter), and I can tell you that the US is already showing signs of declining in its lead in the sciences. While we are still very strong, many other regions (eg China and Europe) are also revealing trends of outpacing us.

    At the 2006 March Meeting [aps.org] of the American Physical Society, some of us physicists (students and professors) went to Washington DC to lobby our Congressmen (see Congressional Visits [aps.org]) about looming shortfalls of hard sciences in the USA and to encourage them to vote on upcoming bills to increase science funding.

    There is alot of eye-opening data showing how Europe and Asia are significantly outpacing the US in terms of funding basic science education, in terms of the number of undergraduate and graduate degrees in the basic sciences, etc. Graphs plotting hard sciences degrees offered per year show the US lagging quite significantly (where we used to be leading 5+ years ago). Such trends are fairly worrisome because the hard sciences are tightly coupled to engineering and industry. Industries tend to attract to places with higher concentrations of scientists, so the US losing scientists will manifest itself in loss of industries down the line.

    These are the kind of things that Senators and Representatives care about. To complicate matters there is a lag between industry and science, meaning that changes in science funding and numbers of scientists now won't be manifest significantly in industry until a decade or longer out. I met with two of my Congressmen and one of my Senators (really with their staffers), who luckily were familiar with this and assured us their bosses would be voting for the upcoming legislation to increase funding.

    I come from a blue state, where the Congressmen are usually liberal with such education and funding programs. The red stater politicans were more hostile to funding sciences without seeing immediate industrial rewards. Such short-term thinking in those cases is what is leading to the decline of US scientific leadership.

    On a different note, I've also seen major shifts in the attraction of foreign students to the US over the past few years. The Bush administration his been cracking down on student visas, which is also hurting our lead. In my department, within the past 3-4 years, each year a handful of good students accepted to the program are denied visas to enter the US (usually from China). Well, these guys aren't going to put their career on hold, and they'll go elsewhere. Many more foreign students are going to Canada and Europe, for instance, and the great brain drain that the US was known for the past few decades is beginning to show signs of reversing.

    Anyway, I just wanted to throw in my two cents becuase I specifically lobbied my Congressmen about this very issue only six months ago.

  • Re:Interesting (Score:3, Informative)

    by Elemenope ( 905108 ) on Thursday September 28, 2006 @08:26PM (#16239473)
    Not stable enough. Most mesons have a half-life on the order of milliseconds or less. Besides, there is a theoretical upper limit for clock speed where one clock cycle is shorter than the time it takes for the signal to cross the chip (which, ostensibly, is the amount of time it takes for light to cross about a centimeter), and a more practical limitation that involves the functional switching speed of whatever it is you are building your logic gates out of. The matter/anti-matter occilation observed has a period that seriously pushes those limits.

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