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Scientists Have Detected a New Particle At the Large Hadron Collider At CERN (bbc.com)

New submitter ag144 writes: First time witnessed, the Large Hadron Collider finds predicted double-heavy particle. BBC reports: "Nearly all the matter that we see around us is made of neutrons and protons, which form the centers of atoms. These are made up of three smaller particles called quarks which can be either light or heavy. There are, however, six different types of quarks which combine in different ways to form other kinds of particle. Those that have been detected so far contain at most, one heavy quark. This is the first time that researchers have confirmed the existence of one with two heavy quarks. The research team will now measure the properties of the Xi-cc++ to establish how this new arrangement of quarks behaves and how the strong force holds the system together. They also expect to find more double heavy quark particles. Another unusual property of the particle is that it has two positive charges double that of the proton and it is four times heavier."

8 of 86 comments (clear)

  1. Re:Two Positive Charges? by Anonymous Coward · · Score: 3, Informative

    Yes there is, Anti-Xi-cc++, the anti-particle to Xi-cc++. No, it won't. If you want more powerful electrons just increase the voltage.

  2. Re: Two Positive Charges? by Anonymous Coward · · Score: 3, Informative

    Particles like these are very explody, and are detected by analyzing the debris from their disintegration.
    There is a phenomenon where two electrons pair up to act as one. It's called superconductivity.

  3. A little bit more background by Michael+Woodhams · · Score: 5, Informative

    Quarks come in three "generations". The first, lightest generation has down (mass 4.8 MeV) and up (mass 2.4 MeV). The second generation has strange (95 MeV, a heavier version of down) and charm (1275 MeV, a heavier version of up.) The third generation has bottom (4180 MeV, heaver version of down and strange) and top (172440 MeV, heaver version of up and charm.)

    When they combine into particles, you either get paired quark+anti-quark (e.g. up+anti-down is a pi+ particle) or a triple of same type: quark+quark+quark or anti-quark+anti-quark+anti-quark. (E.g. a proton is up+up+down.)

    This article says the new particle has two charm quarks.

    This article says Xi baryons are a class of particles which have a single up or down plus two more massive quarks: either strange, charm or bottom, and Xi baryons have been known since 1952.

    From this I conclude that when they say "light" quarks they mean down, up and strange. (I was very frustrated that they didn't say what they meant by "light" quarks.)

    --
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    1. Re:A little bit more background by tinkerton · · Score: 4, Informative

      Are quarks free inside atomic nuclei?

      Inside protons and neutrons you could say yes, they're free

      http://hyperphysics.phy-astr.g...

      But protons and neutrons wouldn't be described as free inside the nucleus. That's more like electrons in an atom.

    2. Re:A little bit more background by ceoyoyo · · Score: 3, Informative

      IIRC quarks stay confined in regular nuclei. The "strong force" that holds together nuclei is actually a residual force from the real strong force holding the quarks together.

      To get a quark soup, called a quark-gluon plasma, you need an accelerator.

      Quark stars have been hypothesized as a state intermediate between neutron stars and black holes, with some oddly behaving neutron stars hypothesized to actually be quark stars.

  4. Re:Two Positive Charges? by Anonymous Coward · · Score: 4, Informative

    According to
    http://www.zeit.de/wissen/2017-07/cern-teilchen-baryon-lhc-teilchenbeschleuniger-genf-physik
    the particle, called Xi cc++ lasted for 0.0000000000005 seconds.

    Philipp

  5. Re:Two Positive Charges? by fph+il+quozientatore · · Score: 3, Informative

    Charm Charm Up, actually. The "cc" in the name stands for two charms. IANAPP, but I think we are still very, very far from building particles with enough energy to have two tops -- we observed the first one just a few years ago.

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  6. Re:Two Positive Charges? by Lord+Crc · · Score: 4, Informative

    The top quark has a lifetime on the order of 10^-25 seconds, so short they don't hadronize. So doubt there's any chance we'll make tt particles.