Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 



Forgot your password?
typodupeerror
×
Science News

New Particle Found, the Bottom-Most Bottomonium 119

PhysicsDavid writes "Collaborators on the BaBar experiment at the Stanford Linear Accelerator Center have detected and measured, for the first time after a 30-year search, the lowest energy particle of the 'bottomonium' family, called the eta-sub-b. Bottomonium consists of a bottom quark and an anti-bottom quark bound together by the strong force. The discovery fills in a missing piece of quark physics that will help reveal the nature and behavior of the quarks and the strong force."
This discussion has been archived. No new comments can be posted.

New Particle Found, the Bottom-Most Bottomonium

Comments Filter:
  • by jimbobborg ( 128330 ) on Friday July 11, 2008 @11:24AM (#24153911)

    So this would be the bottom of the bottomonium barrel?

  • Well... (Score:5, Funny)

    by bigstrat2003 ( 1058574 ) * on Friday July 11, 2008 @11:24AM (#24153913)
    It seems this line of research has certainly bottomed out.
    • This was already discovered in 1998 by San Francisco scientists Doctor Madame Dominatrix and her colleague Teenage Nurse. They experimentally determined that the Whiponium strong force caused the bottom quark and the anti-bottom quark to gyrate violently before binding together, emitting a Handcuff particle in a random direction. Afterwards, the bottom quark smoked a cigarette and the anti-bottom quark demanded to be paid.
  • Huh? (Score:5, Interesting)

    by Millennium ( 2451 ) on Friday July 11, 2008 @11:24AM (#24153933)

    Shouldn't a bottom quark and an anti-bottom quark annihilate one another? How do they manage to avoid doing so in this 'bottomonium' state?

    • Re:Huh? (Score:5, Informative)

      by jeffmeden ( 135043 ) on Friday July 11, 2008 @11:33AM (#24154069) Homepage Journal
      The article knows this and many other astonishing things!

      When a bottom quark and an anti-bottom quark are pulled together by the strong force, they form a quark âoeatomâ-much like an electron and a proton come together under the electromagnetic force to create a hydrogen atom.

      Anti-quarks don't behave like anti-matter, despite sharing that awesome prefix.

      • Re:Huh? (Score:5, Informative)

        by blueg3 ( 192743 ) on Friday July 11, 2008 @11:42AM (#24154227)

        No, the antibottom quark is the bottom quark's antiparticle. It's just that antimatter doesn't work quite the way science fiction stories make it sound.

        • Re: (Score:2, Informative)

          by Anonymous Coward

          No, anti-matter pretty much does work the way most Sci-Fi portrays it. However, quarks, while being what matter is composed of, are not matter in and of themselves and thus can behave differently.

      • Re:Huh? (Score:5, Informative)

        by Steve Max ( 1235710 ) on Friday July 11, 2008 @11:58AM (#24154435) Journal
        They will annihilate after some time (the particle's lifetime), but they can be bound together for some time before that happens. Another good example is the \pi^0 (neutral pion), which is made of up and anti-up (or down and anti-down) quarks. It decays after some time to two photons.

        I don't know what is the lifetime of this \eta_b particle or its main decay branch (I haven't RTF BaBar's A and I'm not a QCD specialist), but it should be very short, and the main decay channel should be hadronic (ie, particle jets).
        • Since the 2 particles travel in different directions in time, it should no time at all!
          • what the hell, 2 directions in time?

          • Re: (Score:2, Insightful)

            by Anonymous Coward
            Just because their wave functions look like one is the time reversed version of the other, doesn't mean they actually move in different time directions.
        • by thechao ( 466986 )

          You're gonna need more '$' if you want to make that TeX go.

        • They will annihilate after some time (the particle's lifetime), but they can be bound together for some time before that happens.

          Exactly. The process by which a particle and anti-particle annihilate is electromagnetic, resulting in the production of photons. Since the timescale for electromagnetic interactions is much longer than that for strong interactions (and it is the strong force which binds the b and b-bar quarks in a meson), the meson exists long enough to have a very definite, observable mass. This is measured by reconstructing the 4-momenta of the decay products to form an invariant mass. When plotted in a histogram, a

      • It's probably unstable. Antibottom and bottom can annihilate, but it takes some time to do so, and can act as a compound particle for a short time. eta-sub-b is a kind of meson. http://en.wikipedia.org/wiki/Meson [wikipedia.org]
      • Re: (Score:3, Informative)

        by jschen ( 1249578 )

        Actually, under the right circumstances, anti-particles don't immediately self-destruct. Electrons and positrons (anti-electrons) can form an atom-like species, too, with half-lives on the order of 10^-7 to 10^-10 seconds. Way back in 1971, an entire review of positronium chemistry (ie chemistry of positron and electron as an ato-like species) was published in Angewandte Chemie, a major chemistry journal. (Page 179 for the international edition, published in English.) It's not my area of study, but I came a

    • Re:Huh? (Score:5, Informative)

      by Remus Shepherd ( 32833 ) <remus@panix.com> on Friday July 11, 2008 @11:39AM (#24154175) Homepage

      The same way protons and electrons avoid crashing into each other. The energy states are discontinuous and do not include zero. Once the bottomonium meson reaches its lowest state, it can't lose any more energy, so it can't get close enough to annihilate.

      • By your argument, no particle could ever annihilate its own antiparticle, and yet particle-antiparticle annihilation is a well observed phenomenon.

        The lowest bound state of a particle-antiparticle pair is not, as you claim, stable, but depending on what happens when you run the numbers for any particular type of particle, it may be live for long enough to be observed in the lab. Ultimately it's going to decay from the lowest bound state to a pair of photons. No such decay is going to happen with protons a

      • Protons and electrons are not anti-particles though.

        The better example is positronium, where you have a positron (anti-electron) orbited by an electron (also known as a negatron... no seriously).

        You end up with a particle-anti-particle interacting in a way that has some form of life time... but positronium even in its most stable form doesn't last more than a few milliseconds.

        So, this "bottomonium" would probably be a case where the two quarks are interacting by strong-force to make a Meson, while not annih

        • I thought it went like so:
          electron, anti-electron (aka positron)
          proton, anti-proton (aka negatron)

          but alas, I am wrong :(.
          Anti-proton doesn't get a cool name? Electron's taking negatron just leaves anti-protons with... antitron? That sucks!

          Damn you Irish physicist G. J. Stoney (1826&#226;&#8364;"1911)!
          • by Bloater ( 12932 )

            Anti-proton doesn't get a cool name? Electron's taking negatron just leaves anti-protons with... antitron? That sucks!

            How about "krupton" (loosly "shadow particle")?

      • Actually, electrons in the ground state s orbitals have wavefunctions which significantly overlap with the nucleus. They don't annihilate because the proton is not the anti-particle of the electron: the positron is. Any such annihilation between electrons and protons would violate conservation of baryon number.
    • Shouldn't a bottom quark and an anti-bottom quark annihilate one another? How do they manage to avoid doing so in this 'bottomonium' state?

      I guess in the bottom in the bottom they all get along just fine! =)

    • Re: (Score:3, Funny)

      by Anonymous Coward

      The should have called the particle a "panda". Then we could call it the "pandamonium" state!

    • thats the power of love for ya.
    • No, the force is strong with these two.
    • The Earth orbits the Sun and does not get annihilated by being sucked into the middle of the sun despite being attracted to it by gravity. For the (sort of) the same reason bound states of matter/anti-matter particles can exist without the particles combining and annihilating each other.
    • by dwye ( 1127395 )

      > Shouldn't a bottom quark and an anti-bottom quark
      > annihilate one another? How do they manage to
      > avoid doing so in this 'bottomonium' state?

      Eventually, they do. While they are detector range, however, they can still be orbiting each other. Even if they do break down before detected, you can determine that they were there by a spike in particle energies from a point source that adds up to the mass of that meson.

      You can even make positronium with an suitable accelerator, where an electron and an

  • Is it any surprise that the most laid back particle evar was discovered in California?

    • by Tmack ( 593755 )

      Is it any surprise that the most laid back particle evar was discovered in California?

      More specifically at the SLAC!

      Tm

  • by clonan ( 64380 ) on Friday July 11, 2008 @11:28AM (#24154003)

    I thought quarks could not exist in anything less than triplets....This sounds like a doublet.

    • by Anonymous Coward on Friday July 11, 2008 @11:34AM (#24154095)

      They exist in groups of two or three that create a neutral color charge. For example, a particle can consist of red, green, and blue or of blue and anti-blue.

      • by jollyreaper ( 513215 ) on Friday July 11, 2008 @12:29PM (#24154837)

        They exist in groups of two or three that create a neutral color charge. For example, a particle can consist of red, green, and blue or of blue and anti-blue.

        I'm not surprised that I can't tell the difference between a proper description of quantum mechanics and the ramblings of a drunken madman on the street. What surprises me is that particle physicists have trouble with that as well. The best way I've heard it described, we're used to relating to things on a human scale. We're used to matter at about our size, moving things about with our own hands, seeing physics operate on a human scale. This is what we're used to, this is what we've come to expect, all is fine. But things outside of our natural environment are very odd. Being in space produces very odd results. We can eventually wrap our brains around it but those things are still odd. At the QM scale, things go from odd to perverse. We can experimentally validate that our seemingly addled theories are correct but it doesn't make any kind of neat and proper sense. The classic scientist saw an exploration of nature as a discovery of the working of the mind of God, a mind we of course imagine in the ideal of our own human mind. Stars on their courses, planets in their orbits, everything neat and prim and orderly. No wonder so many bright scientists reacted in disgust when they looked at the implications of QM. If this is a picture of the mind of God, he's a bloody nutter.

        • by k_187 ( 61692 ) on Friday July 11, 2008 @12:46PM (#24155087) Journal

          I'm not surprised that I can't tell the difference between a proper description of quantum mechanics and the ramblings of a drunken madman on the street

          That's what makes quantum mechanics so AWESOME

        • Re: (Score:3, Informative)

          by drinkypoo ( 153816 )
          I believe it was Niels Bohr who said that if you do not find quantum mechanics confusing you do not really understand it. But then, he didn't really understand it either :D (There's still more to learn/discover...)
        • by krlynch ( 158571 ) on Friday July 11, 2008 @01:29PM (#24155717) Homepage

          I'm not surprised that I can't tell the difference between a proper description of quantum mechanics and the ramblings of a drunken madman on the street.

          I don't mean to sound like I'm ripping on you, but QM isn't really that fundamentally "weird" or difficult to understand, or "odd" at this point in history; it's not any more complicated to wrap your brain around than classical mechanics, or E&M, or automobile maintenance. The "romance" that QM (like Relativity) is "hard" is, I think, a remnant of early popularizations of cutting edge research in the 1920s and 1930s, when a coherent theoretical framework was under construction for the first time, and physicists didn't really know how far down the rabbit hole went. Popularizers were desperately flailing around, looking for analogies that a much more rural and less technically sophisticated public could understand, and to whom they had trouble relating (the "they're all bumpkins" fallacy). We physicists were pretty inept at doing so then, and have been particularly inept at eradicating those early and incorrectly popularized notions from our public interactions to this day.

          Today, we should know better ... most of QM is robust and mature enough that it's an engineering discipline, for cripes sake. Hopefully, the popularizations will catch up with the reality at some point, and we won't keep subjecting generations to the "QM is so weird you can't possibly understand it unless you're a genius" meme.

          • The study itself may not be weird, the terminology is really fucking weird. Consider what that guy was responding to:

            They exist in groups of two or three that create a neutral color charge. For example, a particle can consist of red, green, and blue or of blue and anti-blue.

            To the average person, that's going to sound really fucking crazy. Most science just sounds complicated if you don't know much about it, QM sounds like the scientist is stark raving mad because of the weird terminology that it uses.

            • by Anonymous Coward on Friday July 11, 2008 @03:44PM (#24157749)

              Every discipline has its own jargon. To me, a quantum chemist, what biologists say sounds weird. It takes a while to understand the jargon of a discipline. In case of quantum physics, the terminology is probably confusing because:
              1) you have to "name" something in order to talk about it.
              2) the naming is proposed during meetings/conferences where either the catering is more interesting, the flight back is imminent, or you have too many things in the brain to care about what the hell the name is. If you are not into acadamia, you should try to live as one, and you would understand why this happens. It is not easy, believe me.
              3) no one has yet a clue. Previous examples are Phlogiston theory, the Ether, and the Armillary sphere. You have to refine your model, and the current model seems to explain experimental evidence quite well, but things are too complex, and we got used to the fact that nature is normally quite simply described when you have a powerful mathematical framework. After all, you can explain all quantum chemistry with a very simple formula, H * psi = E * psi, the Schroedinger equation.

              Going back to the issue of difficulty of quantum chemistry/physics: yes, it is hard to understand, because it looks unnatural, but once you understand the mathematical framework, and the meaning of it in practice, the stuff you handle and the rules you apply are always the same, and things behave in a very predictable way.

              • Funny, I thought the point of QM was that it was UNpredictable.

                Predictable unpredictableness? And you people wonder why outside observers think your topic of study is weird. ;)

          • by Pauli ( 72610 )

            QM may not be all that difficult to "wrap your brain around" if you neglect spin, but I defy you to give me a verbal explanation of spin that is simple and accurate in all situations.

          • I pretty much disagree with that. Most engineering disciplines are reasonably intuitive on some level, and use macroscopic behaviour that most people can understand. They may not get all the immediate consequences, but most things there are somehow 'what one might reasonably expect'. I am a physicist working on medium energy scales, similar to BaBar, and I don't find most stuff intuitive at all! Particle creation is fine and dandy, but predicting the other behaviours in a multi-particle system is not obviou
        • I've no idea what you're talking about. The rules for what groups quarks can exist in are simple enough that they could be explained to a child. The weirdest thing about QM is the way people repeat the mantra "QM is weird". There are some weird things about QM, but the rules for combining quarks are straightforward, Unfortunately, because of people like you blathering on with the same old mantra, people feel like they might as well turn off their brains even when the simplest things are explained to them th
          • Re: (Score:3, Insightful)

            by Loki_1929 ( 550940 )

            First of all, drop the "it's so simple a child could understand it" attitude. In a room full of geniuses (ie 120+ IQs), maybe half can have this stuff explained to them on a better than absurdly simplified level. Get deep into the mathematics and you're down to about 5%.

            Secondly, "what the hell is so weird" about what you just talked about?

            Gee, I dunno, how about the fact that you have to combine things that can't exist to get something that can?

            Yes, I realize that mathematically, manifesting energies in va

        • Well, this is actually, nearly as I can tell, the entire argument between atheism and, well, serious religion.

          If we assume that certain ancient Greek philosophers were correct and God should meet human ideals, the atheists must be right and a person tends to make his Gods in his own image.

          But guy called Isaiah [lds.org] and a guy called Benjamin [lds.org] indicated that God is a bit beyond us. This makes sense, if you think about it, if God is immortal. An immortal man would likely have views that mortals would prefer to consi

          • (For my part, I've considered both trusting and not trusting, and it seems to me that refusing to trust can have no advantage over trusting, but trusting might have some advantages.)

            Game theory (using the iterated Prisoner's Dilemma, natch) seems to indicate you're correct. In fact, forgiveness in addition to trust appears to be the optimum strategy, last time I read about it.

      • They exist in groups of two or three that create a neutral color charge. For example, a particle can consist of red, green, and blue or of blue and anti-blue.

        What about a hyper intelligent shade of the color blue?

        tm

      • Is that a real explanation or an analogy? I've never heard it put that way, and now that I think about it (with my limited knowledge) it's a pretty freaking awesome way to describe it. And convenient, unless you work in CMYK.
    • by Jamu ( 852752 ) on Friday July 11, 2008 @11:35AM (#24154099)
      They just have to be "color"-neutral so (red, green, blue) and (red, anti-red) are both allowed.
      • by gr8_phk ( 621180 )

        They just have to be "color"-neutral so (red, green, blue) and (red, anti-red) are both allowed.

        Why does this statement make me think of quaternions?

    • by Remus Shepherd ( 32833 ) <remus@panix.com> on Friday July 11, 2008 @11:37AM (#24154143) Homepage

      It is a doublet, also known as a meson. They're not long-lived, but they exist.

      I have no idea why they didn't use the word 'meson' in the article. Bottomonium is a type of quarkonium, which is a type of meson.

    • Yes, but. One of the two is an anti-quark. So while you need three (regular) quarks to get a chromodynamically balanced particle (red+blue+green=0), green+antigreen (for example) is also balanced.

      (Excuse the naive liberties taken to explain the concept. Let the pedants now correct this statement down to incoherence.)

    • by mapsjanhere ( 1130359 ) on Friday July 11, 2008 @11:38AM (#24154161)
      Our stable particles are made of triplets. There are all kinds of doublets in the particle zoo; the fact that they are unstable makes them observable (since we usually detect not the particle but its decay).
      • I love zoos. Can I pet the yellow part of a meson?

      • There are all kinds of doublets in the particle zoo; the fact that they are unstable makes them observable (since we usually detect not the particle but its decay).

        You have this argument backwards. The reason we detect decay products from particles is BECAUSE they decay! Stable particles are often very easy to detect e.g. electron, proton, muon (ok, technically this is not stable but it is so long lived at high energy that we usually treat it as stable). In fact stable particles are generally a lot easier to detect than unstable ones because we detect the particle itself, and not its decay products.

        Since all our detectors are made of matter what determines whether

    • Not being the physics geek I once was, I was slightly confused by your use of the word 'doublet'.

      Thank Google for Just In Time Comprehension.

      -Rick

    • You thought wrong. Combinations of quarks form hadrons. There are two types of hadrons: baryons (formed from 3 quarks or 3 antiquarks) and mesons (formed from a quark and an antiquark). There's speculation that there could be higher number groups like 4 quarks and 1 antiquark. The only restriction is that the combination be color neutral. An antiquark of the same color can neutralize a quark, or three quarks of different colors are together neutral.
  • I thought Cowboi Neal had that distinct honor.
  • by spooje ( 582773 ) <spooje@hot m a il.com> on Friday July 11, 2008 @11:34AM (#24154085) Homepage

    The bottom and anti-bottom held together by the strong force?

    Sounds cheeky to me

    • by JohnFluxx ( 413620 ) on Friday July 11, 2008 @11:56AM (#24154409)

      I was reading a book on this last night, and it said that scientists named it that just so that they could publish papers about searching for a 'bare bottom' ( A bottom quark by itself ).

      The book said that the silly names assigned to the quarks was because at the start nobody took quark theory seriously. Nobody expected the theory to last, so they assigned silly names.

      • by khallow ( 566160 )
        OTOH, what names would be serious in this context? Naming them after trios of politicians or physicists?
      • by badfish99 ( 826052 ) on Friday July 11, 2008 @01:18PM (#24155565)
        Actually, the top and bottom quarks were originally named truth and beauty. They were renamed to top and bottom because the original names were thought to be silly. Names like top and bottom count as sensible in the context of quantum mechanics.
        • by dpilot ( 134227 )

          I seem to remember hearing a while back about the search for "naked Truth" or "naked beauty".

        • It took the researchers much longer to determine which one was the power-bottom

        • Re: (Score:3, Funny)

          Truth decays into beauty, while beauty soon becomes merely charm. Charm ends up as strangeness, and even that doesn't last, but up and down are forever.
    • Yes. The force is strong with this one.

  • by Mikkeles ( 698461 ) on Friday July 11, 2008 @11:34AM (#24154093)

    '... the BaBar experiment at ...

    Shouldn't this be called Elephantonium?

  • by 0racle ( 667029 ) on Friday July 11, 2008 @11:36AM (#24154119)
    bullonium.
  • by R2.0 ( 532027 )

    "None more bottom."

  • Now, for the first time, collaborators on the BaBar experiment at the U.S. Department of Energyâ(TM)s (DOE) Stanford Linear Accelerator Center (SLAC)...

    I mean, I guess this experiment has nothing to do with testing on animals [wikipedia.org]

  • by merlinokos ( 892352 ) on Friday July 11, 2008 @11:52AM (#24154371)
    The interesting question, IMHO, is: Was this particle predicted by anybody else's research? I remember an alternative theory being mentioned a while back that proposed An Exceptionally Simple Theory of Everything [slashdot.org] that included predictions for 5 new particles. If this one is on his list, where he said it would be, it could be a big step for non-string theory theories.
  • I mean come on... I've heard of the force, and the dark side of the force. But WTF is "the strong force"? I've heard "The force is strong with this one" but that's simply referring to the state of "the force" not "the strong force."

    • by everphilski ( 877346 ) on Friday July 11, 2008 @12:06PM (#24154549) Journal
      The strong force would be the sticky side of the duct tape, and the weak force would be the opposite side of the duct tape, which is still useful but not as strong.
    • by 4D6963 ( 933028 ) on Friday July 11, 2008 @01:25PM (#24155665)

      Here it comes :

      Bottomonium consists of a bottom quark and an anti-bottom quark bound together by the strong force

      I feel a great disturbance in the strong Force, as if millions of bottom and anti-bottom quarks were bound together in the Upsilon(3S) state and suddenly decayed by emitting a gamma ray.

    • Re: (Score:1, Informative)

      by thedrx ( 1139811 )
      The strong force is one of the four fundamental forces. They are gravitation, EM force, weak force and strong force.
      • by alta ( 1263 )

        You seem to know a thing or two about this subject. So, just where to the midichloridians come in?

  • Bottom, Top? (Score:4, Interesting)

    by JSBiff ( 87824 ) on Friday July 11, 2008 @12:31PM (#24154871) Journal

    I'm confused - at an atomic scale, what is top and bottom? I thought space has no 'preferred' direction in which to define up, down, east, west, north, south? How can there be a 'bottom' particle?

    • Re:Bottom, Top? (Score:5, Informative)

      by icegreentea ( 974342 ) on Friday July 11, 2008 @12:40PM (#24155013)
      Bottom (and top and up and all the colours) are arbitrary names chosen by the scientists who discovered/theorized these particles. The names do not describe the properties of the particles in any way. You'll have to go ask them why they picked these names, but personally I think it's because they got bored of Greek and Latin.
  • looking at anti-particles from the standpoint of reverse entropy (going back in time).. the strong force here seems to be the release and absorption of the energy released... OR the strong force is keeping the two from colliding, acting - in a reverse entropy sense as a repulsion.
    I am, obviously, not schooled in this whole mess of stuff, but it's interesting to think about (even if my thoughts are fiction). How fun!
  • ...to discover the bottom-most bottom's "safe word"? Then, surely, we will be near to achieving a Theory of Everything.

  • Bottomonium consists of a bottom quark and an anti-bottom quark bound together by the strong force.

    And we wonder why people think scientists are just making things up.

    (I was going to say 'talking out of their asses' but remembered what I was quoting while typing it.)

Technology is dominated by those who manage what they do not understand.

Working...