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LHC Discovers New Particle That Looks Like the Higgs Boson

The wait is over: new submitter Roger W Moore (among many, many other submitters) writes "The ATLAS and CMS experiments at CERN have just announced the discovery of a new particle which is consistent with a Standard Model Higgs boson. There is still a lot of work to do to confirm whether this really is the Higgs, and if so whether it is a Standard Model Higgs, but this is a major result."

25 of 396 comments (clear)

  1. Dr. Higgs himself said it best... by klmth · · Score: 5, Informative

    In the press conference, Dr. Higgs summed the findings up nicely: "This is an achievement in experimental methodology." To detect this signal has required a momentous effort, and the good people at CERN have had the good fortune of reaching results quicker than anticipated.

    This isn't earth-shattering news or anything even unexpected, but it is still cause for celebration. Let us rejoice and then continue to push on towards new findings.

    1. Re:Dr. Higgs himself said it best... by toruonu · · Score: 5, Interesting

      Well it's not that much good luck really. CMS showed the expected significance of a SM Higgs boson for the full 5 channel combination to be ~6 sigma for 125 GeV. So seeing 4.9 sigma is actually a downward fluctuation (or in other words unlucky) or it's not Higgs.

      Also, it's odd to see how much worse ATLAS was. They got 10% more statistics, yet see about the same significance as CMS. They also presented only 2 channels (true, the most sensitive ones) and didn't even attempt to fit the mass of the new particle (while CMS gave 125.3 +- 0.6 GeV, a precision of 0.5%!!!) nor did they look at the other supporting channels that could indicate if this is SM Higgs or some other particle. CMS as an example sees some tension in the 2tau final state where there is actually a downward fluctuation and almost exclusion of SM Higgs. CMS also showed first fits of couplings to fermions and bosons and that was very interesting result. ATLAS just claimed the 5 sigma and approximate mass. Really expected more of them...

    2. Re:Dr. Higgs himself said it best... by toruonu · · Score: 5, Informative

      I'm in CMS and we pretty much released all the details now at the seminar. If ATLAS held back until publication, then either they didn't manage to get it approved or they cut corners and didn't feel presenting the results right now yet. In any case it's CMS that showed most thorough investigation here. Though I can understand delaying the lower priority channels until some time this/next week I don't understand why they didn't provide a mass fit at todays seminar which was to be a discovery seminar (or they didn't expect CMS to have 5 sigma).

  2. A good introducton to the Higgs mechanism by anandrajan · · Score: 5, Informative

    Here's a good introduction to the Higgs boson and why it matters.

    --
    Anand Rangarajan anand@cise.ufl.edu
  3. Re:Found at 125 GeV by Remus+Shepherd · · Score: 5, Informative

    The Higgs particle is just the particle manifestation of the Higgs gauge field. Think of it as a huge block of jello through which all massive objects move. 125 GeV is the energy required to scoop out a bit of that jello and isolate it.

    --
    Genocide Man -- Life is funny. Death is funnier. Mass murder can be hilarious.
  4. Re:Careful Announcement by klmth · · Score: 5, Informative

    That's because they're not in competition as such. The results are complimentary. The Tevatron was able to isolate the same signal, just to a lower degree of precision (2.9 sigma as opposed to 5.0 sigma).

  5. Re:Massive by jampola · · Score: 5, Funny

    That's what she said.

    Sorry, 6 beers in and I couldn't help myself :)

  6. Worth the waking hours by Pro-feet · · Score: 5, Interesting

    I made it in the auditorium after queueing through half the night, but it was totally worth it. The atmosphere was collegeial and almost rapturous, one of sharing a feeling that we have as a whole community worked for so long to prove some mathematical construction of almost 50 years ago to be really realized in nature.

    And let it now please NOT be a standard-model Higgs boson, but something a little more intriguing!

  7. Re:Found at 125 GeV by Pro-feet · · Score: 5, Informative

    No, no, it is really the particle's mass.

  8. Re:Found at 125 GeV by tmosley · · Score: 5, Funny

    That sounds disturbingly like aether theory.

  9. Possibly something else by Twinbee · · Score: 5, Informative
    It's something, and probably the Higgs Boson, but we're not 100% sure. Here's a comment from a CMS worker:
    http://www.reddit.com/r/science/comments/w0tty/higgs_boson_confirmed_at_5sigma_standard/c599ijb

    Actually, we observed a new state at 125 GeV and it seems consistent with a Standard Model Higgs boson. We have NOT discovered the SM Higgs boson because we simply haven't confirmed that this new particle is the SM Higgs because we're only looking at mass itself. It could be something else with a mass of 125 GeV. To actually claim it is the SM Higgs, we need to confirm that it has spin 0, the right coupling ratios, etc. And that's what I'm working on right now. But it is very exciting because we have discovered new physics. Source: Working at CMS

    --
    Why OpalCalc is the best Windows calc
  10. Particle That Looks Like the Higgs Boson by Higgs+Bosun · · Score: 5, Funny

    So, they might be mistaken. They've probably just detected me and got confused.

  11. Re:huh by Rei · · Score: 5, Informative

    Now we just need to solve gravity, dark matter, dark energy, unify quantum chromodynamics with relativity, and a ton of other stuff.

    Party's not over, folks. :)

    I suspect dark matter will be easiest. Wouldn't be surprised at all if the LHC solves that one. All you need to see is what looks like a clear violation of conservation of energy/momentum at a consistant, high energy in your results, and you've got evidence that something heavy that interacts weakly or not at all with normal matter is flying off in the opposite direction. That something would probably be dark matter.

    The others... that's probably going to be a long, hard slog.

    --
    Rock Us, Dukakis.
  12. It is the mass by Roger+W+Moore · · Score: 5, Informative

    The mass of the Higgs boson is just the energy needed to make the Higgs field vibrate. The reason that the Higgs field gives particles mass is that, at its lowest energy level, the value of the Higgs field is not zero and this non-zero field then fills the universe and binds to particles giving them mass.

    Hence the mass of each type of particle depends on the zero energy value (vacuum expectation value) of the Higgs field and how strongly the particle couples to it while the mass of the Higgs boson depends on how the energy density of the Higgs field changes as the strength of the field varies.

    1. Re:It is the mass by Cow+Jones · · Score: 5, Funny

      [the Higgs field] ... then fills the universe and binds to particles giving them mass.

      I'm not a physicist, so please correct me if I misunderstood. Are you saying that this field surrounds us and penetrates us, and that it binds the galaxy together?

      --

      Ah, arrogance and stupidity, all in the same package. How efficient of you. -- Londo Mollari
  13. Re:I found it last week. by erdos-bacon+sandwich · · Score: 5, Funny

    The legendary Higgs Boson is in my pants, and it feels great!

    Scientists also report the particle is much smaller than expected

  14. Patent applied for by Harold+Halloway · · Score: 5, Funny

    Already Apple have patented the new particle, on the basis that it gives the iPad mass so they must have invented it.

  15. Re:I found it last week. by Anonymous Coward · · Score: 5, Funny

    It's also not a Hadron.

  16. Re:Found at 125 GeV by dkf · · Score: 5, Interesting

    Photon propagation is affected by gravity, though.

    But the Higgs mechanism isn't there to explain gravity. It's there to explain why some particles have rest masses at all. AIUI, a large part of the mass of a proton or neutron is explained by the energy stored in the Strong Nuclear binding field that couples the component quarks, but the Higgs mechanism is there to explain the rest.

    --
    "Little does he know, but there is no 'I' in 'Idiot'!"
  17. No, not really by Anonymous Coward · · Score: 5, Informative

    The field is everywhere, not just around us but also inside us. Everywhere and anywhere. Comparable to electromagnetic fields, except you can't shield them.

    What holds the galaxy (-ies) together is something else, that's gravity. Also a field, extending to fill the universe.

    The Higgs particle (or field, can't talk about one without thinking about the other) gives the universe mass (well, it's one of the things that do that) so perhaps some clever brainiacs might be able to think something up connecting the Higgs and gravity in such a way that it unites all the forces. That would be a garuanteed ticket to Stockholm and a place in history as the greatest discovery (or theory, if you like) since the discovery of fire itself.

    1. Re:No, not really by Anonymous Coward · · Score: 5, Funny

      Just in case you, or someone else, didn't get the reference:

      The Force

      How is explaining a Star Wars reference on slashdot considered informative? That's like explaining what a bullet is on a gun forum.

      Now, explain how to dress, how to coordinate an outfit or what breasts feel like... that would be informative

      Your audience, know it.

  18. Hmmm... by Anonymous Coward · · Score: 5, Funny

    Thanks, you're right that I didn't get the reference. In retrospect it is obvious...

    In my defence I'd like to offer that on a regular day about 67% of my brain activity goes to suppressing the memory of JarJar "MeesaSuckSoBadly" Bincks.

  19. Re:Found at 125 GeV by Calos · · Score: 5, Informative

    That's shorthand, it's GeV/c^2, which is in fact a mass.

    --
    I vote based on politicians' actions, unless contrary to my preconceptions. Often wrong, never uncertain. #iamthe99%
  20. Re:explanatory update please? by Anonymous Coward · · Score: 5, Informative

    Ok, this is going to be pretty rough, but here it goes:

    The Standard Model describes all the "point particles" which can't be subdivided. Each of these particles has a few constant parameters like electric charge, color charge, mass, and spin. Electrons are one of them (-1e charge, 0.51MeV mass, spin 1/2) as are neutrinos (0 charge, some...mass, spin 1/2) and quarks (+2/3 or -1/3 charge, a few different masses, spin 1/2). Quarks come together in groups of 2 or 3 to build particles like protons and neutrons (and a whole bunch more). These are what you'd consider matter (Fermions). There are also particles that serve as "force carriers" - all the fundamental forces like electromagnetism and the nuclear forces can be thought of as exchanges of these other particles. They have integer spin, and we call them Bosons. The photon for instance represents the electric field (it's massless), the W and Z bosons represent the weak nuclear force (they have mass), and Gluons represent the strong nuclear force (they have color charge, like quarks).

    The problem is that gravity isn't really mentioned anywhere in here, and unlike all the other particle parameters, "mass" seems pretty arbitrary. It's not a nice round number, so there has to be something else there behind the scenes. The solution to this is that we think there's another "field", which we call the Higgs field, and another force-carrying particle called the Higgs Boson. In the same way that particles with charge can interchange photons to "feel" the electric field, particles with mass can exchange Higgs bosons to "feel" the Higgs field. Particles that interact that way essentially tie up a bunch of energy in that reaction, and that extra bottled up energy is what we experience as mass. So the degree to which particles couple to the higgs field (you could think of it as their "mass charge" parameter) determines how much mass they have. And people way smarter than you and me have found equations that do, in fact, predict the right masses for various particles when you crunch the numbers.

    The problem with finding bosons is that they're really just intermediary particles - photons are obvious enough only because they travel at the speed of light. Bosons with mass go much slower, and wind up decaying or interacting before we can directly observe them. So this find by the LHC is *indirect* evidence of the Higgs, based on how much energy they're missing from various collision interactions. But it matches the predictions to a very high degree so far, so they're calling it good.

  21. Re:Found at 125 GeV by Carewolf · · Score: 5, Informative

    Where does a wave on the ocean go? The "particles" are manifestation of a particle(or force) field, which is like an ocean with waves on it. These waves are called particles when they collide and collapse with something else, but are otherwise waves when they move around on the ocean. There is always some waves on the ocean but not always high enough waves to break over the sea-barrier. The sea barrier in this case is 125GeV.