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New Bounds On the Higgs Boson Mass 173

Posted by kdawson
from the pulling-in-the-walls dept.
As the LHC continues to run at half power for the next year+, the US-based Tevatron continues to crank out results. Reader hweimer writes "Three new papers in Physical Review Letters present the latest results for the Higgs boson mass coming from Fermilab's Tevatron. The new data mandates that the Higgs boson mass within the standard model lies between 115 and 150 GeV." A year back we discussed the Tevatron's previous shrinking of the search space for the Higgs "God particle."
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New Bounds On the Higgs Boson Mass

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  • by cytoman (792326) on Monday February 15, 2010 @08:03PM (#31150570)
    1 GeV/c^2 = 1.783 x 10^-27 kg.

    I didn't preview my previous comment and so it came out all wrong.

  • Re:wasteful (Score:2, Informative)

    by Cryacin (657549) on Monday February 15, 2010 @08:09PM (#31150620)
    That's beyond his cranial capacity.
  • Re:Aw shucks... (Score:5, Informative)

    by JoshuaZ (1134087) on Monday February 15, 2010 @08:16PM (#31150688) Homepage
    Note that they didn't find the Higgs boson, just got narrower upper and lower bounds on the rest mass. In any event, even if the Tevatron had found the Higgs boson, that wouldn't make the LHC useless. The LHC is going to be used for many things other than the search for Higgs boson. For example, the LHC will be useful for finding supersymmetric particles. If we are to progress at all beyond the Standard Model, such particles almost certainly need to exist. Even given the minimal supersymmetric model http://en.wikipedia.org/wiki/Minimal_Supersymmetric_Standard_Model [wikipedia.org], we still get a lot of other particles. Those particles will be much more easily detectable and analyzable with the LHC than with the Tevatron or any other lower energy collider.
  • Re:wasteful (Score:2, Informative)

    by dissy (172727) on Monday February 15, 2010 @08:35PM (#31150826)

    and finding it would have zero impact on the worlds population

    Do as you say, troll.

    If you don't think computers are of any impact, then you should give yours away and get off the Internet. Both are technology that exists because of science which as you say is pointless.

    I guess to a troll, that statement pretty much is true. One can be an asshole without the aid of any technology.

  • by dr_tube (115121) on Monday February 15, 2010 @08:40PM (#31150856)

    It makes sense. It 'gives' mass to other particles by interacting with them, 'knocking them back' when they start to move (simplified, but that's the basic idea). It also interacts with itself, giving itself mass in the exact same way it gives mass to other particles.

  • by mbone (558574) on Monday February 15, 2010 @11:20PM (#31151778)

    The new data mandates that the Higgs boson mass within the standard model lies between 115 and 150 GeV."

    No, it doesn't. Look at this graph [aps.org]. At a "3 sigma" level (and don't believe any new science that is not at the 3 sigma level or better), the mass of the Higgs (assuming it exists) is roughly between 115 and 225 GeV. To put it another way, a mass greater than the Tevatron exclusion zone at ~160 GeV is by no means ruled out.

  • Troll? Seriously? It was a joke -- if you laughed then mod the guy funny, if not then leave him alone.

  • Re:I'm lost. (Score:2, Informative)

    by domulys (1431537) on Tuesday February 16, 2010 @12:03AM (#31152000)
    It so happens that there is a "simple English" version of that wikipedia entry:

    http://simple.wikipedia.org/wiki/Standard_Model [wikipedia.org]
  • by TheEldest (913804) <theeldest.gmail@com> on Tuesday February 16, 2010 @01:06AM (#31152316)

    The higgs is sort of the measureable side effect of the physics that 'give' particles mass.

    Think of it this way. The Electro Magnetic field "gives" particles charge. (or the charge in a particle interacts with other charges through the EM field).

    There are some particles that sorta 'show up' in the equations when you're dealing with the EM fields (photon, W & Z bosons).

    The same sort of things happens with mass. Some physicists came up with an addendum to the current equations that would explain how the mass of particles interacts. These equations have in them (depending on version) 1 or more particles (Higgs bosons).

    So it's not so much that the Higgs gives particles mass, but by detecting the Higgs, we prove the existence of the Higgs field which allows mass in particles to interact.

  • by JohnFluxx (413620) on Tuesday February 16, 2010 @04:46AM (#31153358)

    2 sigma means a 95% certainty, and 3sigma means a 99.7% certainty.

    So at just 2 sigma, 1 in 20 times you will get it wrong/fail. I would hope that in medicine and biochemistry, where it matters, that they do use 3 sigma certainty.

    In particle physics, a 5 or 6 sigma certainty is usually used for confirming a new particle, which means that you're wrong only once in a couple of million times (although guessing at the errors is probably itself the most significant error.

  • Re:I'm lost. (Score:5, Informative)

    by zmooc (33175) <`ten.coomz' `ta' `coomz'> on Tuesday February 16, 2010 @06:27AM (#31153702) Homepage

    particle physics for dummies

    ALL (anti)matter, ALL forces, fields and waves and everything you can think of consists of particles. I'm not talking about neutrons and protons and the such, but even smaller particles known as subatomic particles or elementary particles. Most of us know the group of particles called quarks, but there are more groups of particle with cool names like leptons (an electron is a lepton) and bosons (a photon is a boson).

    We know that a LOT of nature shows some kind of symmetry; this is the same in elementary particle physics. From this, it has been deduced that several particles not yet detected must exist in order to fill in the gaps in the symmetry. It is those particles we are looking for and they are predicted by the Standard Model, which is an enourmous collection of theories that together attempt to describe our entire universe (with the exception of gravity) (and to unify the newtonian and einsteinian physics).

    Such particles have many hard-to-understand properties like spin, charge, mass etc. What we are looking for, however, is their specific energy. We do this by accelerating matter (protons typically) to incredible speed and then colliding it. In such a collision, enormous energies occur that cause elementary particles to cease to exist and create new elementary particles. All kinds of particles can sort of randomly be created during such a collision, but obviously the collision itself has to be powerful enough to reach at least the energy the particle we're looking for has. So we keep building more and more powerful particle accelerators in order to find these things. What we call the energy of such a particle is a bit complex; it sort of comparable to mass*speed, but that's not all there is to say about this; for example many particles have a fixed speed, namely the speed of light. Therefore, their mass is equivalent to their energy. That's the GeV number we're talking about here. Note that this is incredibly simplified; for example we don't really know the mass of the photon (except that it is 0 in rest, but photons don't exist in rest) but we DO know its' energy since we can measure that. Also, the charge is not factored into this equation. But, in general, elementary particle physicists think in "energy", not in "mass" or "speed".

    Anyway, around the point of collision, enormous detectors have been built that attempt to trap the particles created in the collision. These detectors generate a small electric current comparable to the energy of the particle that collided, which is measured. Think about them as antenna's. After millions and millions of such collisions, patterns start to emerge and we can deduce a specific particle has been created in our collisions. For example, you see a lot of collisions with this energy and a lot with that energy, but none with energy such and so. The result is sort of like a spectrogram (but again, it's way more complex than that).

    So in the case of the Higgs Boson, in this "spectrogram", we're looking for a peak somewhere between 115 and 150 GeV. This is obviously an incredibly simplified explanation, but I think this should make you understand just a bit more.

  • by dylan_- (1661) on Tuesday February 16, 2010 @08:16AM (#31154066) Homepage

    I doubt any physicist would refer to the Higgs boson as "God particle"

    Except that the phrase was coined by Nobel Prize-winning physicist Leon Lederman.

  • by JamesP (688957) on Tuesday February 16, 2010 @08:51AM (#31154204)

    2 sigma means a 95% certainty, and 3sigma means a 99.7% certainty.

    So at just 2 sigma, 1 in 20 times you will get it wrong/fail.

    It doesn't work that way...

    I would hope that in medicine and biochemistry, where it matters, that they do use 3 sigma certainty.

    No, they use usually btw 90/95% (if not lower).

    Also, WHAT, 3sigma is a huge space (especially in this kind of experiment).

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