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Higgs Territory Continues To Shrink 118

PhysicsDavid writes "Announced this morning by Fermilab, the possible territory for the Higgs boson has shrunk even further. Combined results from the CDF and DZero experiments at the Tevatron have ruled out the existence of the Higgs with a mass between 160 and 170 GeV/c^2 with 95% confidence. At 90% confidence the Higgs is ruled out between about 157 and 185 GeV/c^2. Here is Fermilab's press release. If the Higgs is to be found at the lighter end of the currently allowed range of 114 GeV/c^2 to 185 GeV/c^2, its detection will be harder than at the heavier end due to the kinds of signals that the Large Hadron Collider and the Tevatron will see. Some physicists think that a lighter Higgs will be easier to spot at the Tevatron as the background processes which obscure the faint signal are not as prevalent in those experiments."
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Higgs Territory Continues To Shrink

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  • Boring... (Score:3, Informative)

    by Maury Markowitz ( 452832 ) on Friday March 13, 2009 @12:10PM (#27181895) Homepage

    The fact that this is all that's left of high energy physics says a lot. The worst possible outcome is that they actually find the thing.

  • Easier vs. Harder (Score:5, Informative)

    by n0mad6 ( 668307 ) on Friday March 13, 2009 @12:29PM (#27182197)
    Its not a matter of "some thinking"-- the backgrounds that swamp a Higgs signal for a low mass Higgs are simply more prevalent at the energies of the LHC. The LHC makes up for that by being able to accumulate much more data than the Tevatron in a shorter amount of time. Of course, up to probably early next year, we at the Tevatron are in a superior position in that any data is greater than the zero the LHC will have accumulated.
  • by n0mad6 ( 668307 ) on Friday March 13, 2009 @12:30PM (#27182213)
    No, there's no guarantee a *Standard Model* Higgs Boson (which is what this search is) even exists. We know some mechanism exists for the symmetry that's broken between the Electromagnetic and Weak forces, but that doesn't necessarily have to be in the form of a standard model Higgs.
  • Re:Not boring! (Score:3, Informative)

    by Roger W Moore ( 538166 ) on Friday March 13, 2009 @10:56PM (#27189697) Journal

    I didn't say 5 sigma, you did. Sure, 5 sigma is the gold standard.

    5-sigma is not the gold standard it is THE standard to claim discovery. 3-sigma is the significance to claim 'evidence'. Less than 3-sigma and you cannot write a paper that people will take seriously. Yes these are arbitrary standards but they are the standards that the field has adopted.

    You seem to be contradicting yourself here. First you say "I find this far less likely," and then you say that such statements about likelihood are not meaningful.

    Actually I said "Personally I find this far less likely than finding Dark Matter but it is certainly a possibility.". The indication being that I am expressing my opinion (based on the problems that such models have accommodating baryon number violation). There is no contradiction between having a personal opinion about how likely something is versus knowing how likely something is. It might be a subtle distinction but it is a very important one.

  • Re:Not boring! (Score:3, Informative)

    by Roger W Moore ( 538166 ) on Saturday March 14, 2009 @12:40AM (#27190193) Journal

    The only reason we're looking for the Higgs is because we can. We simply don't have any other HEP we can do. Every alternative theory so far needs energy levels at least an order or two of mag more than LHC to even approach usefulness

    I return to my remark that the fact that you say this shows that you do not know a lot about high energy physics. The reason we are looking for the Higgs is because we have not found it and must find it soon or rule it out which would completely turn the field on its head. Assuming that we do find it there is something called the hierarchy problem that means there is VERY likely to be some new physics below ~10TeV and in reach of the LHC. In addition there is the thermal production argument for Dark Matter which again suggest DM below ~1 TeV. You might be ignorant of these theories but that does not mean that they do not exist.

    HEP is dead. There is another way, however, and it's well on it's already far more interesting. That's astronomy. Every time we turn on the newest telescope we immediately find something that's essentially impossible under current models.

    Really? Ever wonder where the physics used to make and correct the models comes from? I'd love to know how astronomy is going to explain the properties of the particles making up Dark Matter. Indeed all your examples can be summed up as Dark Energy and Dark Matter. These are all different facets of the same "problem". To solve this problem we need particle physics. A good example is the solar neutrino problem - no amount of astronomical observation would ever have been capable of solving this we needed particle physics experiments.

    How many questions has HEP answered in the last 25 years that aren't internal to HEP? None.

    Try looking up the solar neutrino problem - that was an astronomy problem. Heard of the World Wide Web? - invented by particle physicists to solve their communication problems (and yes I am going to include that if you are including making E. Coli smell as an 'advance').

    And HEP's done what in that time? Spend billions of dollars to answer questions they're already utterly convinced they know the answer to?

    What particle physics has been doing is increasing our understanding of the fundamental laws of nature that underpin ALL science. The fact that we have been showing that the Standard Model is very correct is not a failure - we are not an applied science, we can only find what there is to find. Complaining that we have not found new physics would be like berating Columbus for finding the Americas when he set out to find India. However to imply that it is a waste of money to experimentally check an incredibly fundamental question where we think we might already know the answer shows that you really don't understand science at all: it is all about making predictions and then seeing if you got them right.

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