Higgs Search at the Tevatron

Tommaso Dorigo of the CDF collaboration at the Tevatron has just posted (with commentary), the slides for his talk at Moriond later this month about the status of the search for the Higgs at the Tevatron. The bottom line is that with the data they have already analyzed they are still quite a ways from being able to see the Higgs, but, if its mass is just above the lower limit set by LEP2, they should be able to see it by two years from now. With quite optimistic assumptions about the performance of the Tevatron, by the end of 2009 they should be able to see the Higgs if its mass is less than 180 Gev. He ends by saying that at “95% confidence level” he thinks the Tevatron will be able to end up seeing a Higgs up to 135 Gev mass, and if its mass is just above the LEP2 limit at 115 Gev, they should have 3 sigma evidence for its existence.

By 2009, the LHC should be producing data and putting the Tevatron out of the Higgs discovery business. For a bewilderingly complicated schedule of the LHC construction and installation, go here. From what I can tell, they are still on track for first colliding beams in spring of 2007.

Update: See Tommaso’s comment to this posting for a clarification. By “seeing the Higgs” I didn’t mean to imply that they would be able to prove the Higgs was there, just that they would be starting to see some evidence of its existence.

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15 Responses to Higgs Search at the Tevatron

  1. D R Lunsford says:


    Yes, that’s the paper and the analysis is IMO very solid. One need not take the latter papers as seriously, however it should be mentioned that Penrose also points out how highly implausible it is that electrowesk symmetry breakdown should be the same everywhere in the Universe, as current comso. models assume.

    Note that his analysis is not at all controversial – he’s simply pointing out the consequence of having the Higgs enter into the Lagrangian in just the way needed to supply masses to the gauge bosons, much as in the problem of a ball rolling on a surface as solved with Lagrange multipliers, where the multiplier term represents the “just right” normal force on the ball needed to keep it on the surface. There is also an obvious analogy in the BCS theory of superconductivity.


  2. Alejandro Rivero says:

    Hello again… more magic from physicsforums, this morning. Just do this

    mu/mz+ mu^2/(114.5)^2.

    where mu= 0.105658369
    mz= 91.1876 +- 0.0021

    try some values around mz and compare with

  3. Peter says:

    Hi Tommaso,

    Thanks for the clarification. My use of the term “seeing the Higgs” was intentionally ambiguous, meaning something like “seeing some evidence of the Higgs”, not meaning “proving” the Higgs was there.

    Am I confused or is the situation the following: in 2007, if there is a 115 Gev Higgs, you hope to have a signal 2 sigma different than the null result, no? Do you then write a a paper with the title “Possible evidence for a 115 Gev Higgs” or are you more disciplined than that?

    I very much enjoy your weblog!

  4. Thanks for citing my blog here. However, we claim that in two years the Tevatron can probably _update_ the LEP2 _limits_, which is different from seeing it if it is there! It is typically easier, in fact, to exclude at 95% CL something, than to prove it at 5 sigma (95% is like two standard deviations).
    Same goes for the 180 GeV reach by 2009: we will probably be able to exclude it at 95% CL if we do not see any evidence, but finding it is a totally different matter…

  5. Alejandro Rivero says:

    I am not surprised, Lubos. Physics in the internet was mostly dead except by four or five pages, including Woit and your’s.

    If you want to analyse web relationships, TouchGraph provides a visualizer for the proximity engine of google at http://www.touchgraph.com/TGGoogleBrowser.html

    You can click in any webpage to get more proxies to it, or right-click to go to the page.

    (Needs java. There is also a GoogleScholar version, you could had noticed it in physcomments at the lower left side).

  6. Luboš Motl says:

    Wow, Not Even Wrong is the largest website that refers to The Reference Frame! See the counter on my blog.

  7. Anonymous says:

    After the top discovery at 1/sqrt(2) of the Higgs vacuum, a lot of people will surely enjoy to have the W particle at 1/sqrt(2) of the Higgs.

  8. Anonymous says:


    Electric charge loses meaning above the SM symmetry breaking scale, there is no photon, no speed of light, no time, and hence no gravity. “It is hypothesized here that the Universe came into existence when the electro-weak symmetry was broken spontaneously”.

    I think this qualifies for Not Even Wrong.

  9. Anonymous says:

    drl, i suppose you’re referring to
    http://arxiv.org/pdf/hep-ph/9912243 ?

    “…the full structure of the SM stands intact without constraining the quantum numbers isospin and/or hypercharge of the Higgs to any specific value.”

    “The hypercharge of all the other particles are specified as being proportional to the Higgs hypercharge which itself remains unconstrained”.

    “Higgs is a manifestation of the vacuum structure of the SM. Higgs shall never get pinned down as an isolated physical particle, but makes its presence felt through charge quantization and giving the SM its complete structure and consistency. Hence it is predicted that Higgs shall not be discovered as a particle.

    “No basic principle demands that the mass of the matter particle be given by Yukawa interaction, but since as we have no idea of where these masses come from, one just demands that they arise from such a coupling. If this be so then the Higgs isospin is necessarily T= 1/2. This just tells you that the ‘vacuum’ has this particular structure. But as Y_phi {hypercharge} is not constrained in any way, the Higgs cannot be a particle but just ‘vacuum’ which behaves in this fundamental and basic manner.

    “In summary, we have shown that the basic and fundamental structure of the standard model stands intact without specifying and constraining the quantum numbers of the Higgs. As such Higgs is very different from any known physical particle. Hence Higgs cannot be a ‘particle’ but represents the omnipresent vacuum with provides the ‘root’ to support the Standard Model’

    I think when people talk of finding the Higgs, they mean the Yukawa-coupled Higgs, i.e., a definite isospin. Certainly all the theoretical constraints on Higgs mass come from such models. Since the hypercharge of all the particles are proportional to the Higgs hypercharge, one could equally well set the hypercharge of one of the particles as basic – i.e., if indefinite hypercharge makes the Higgs not a particle, then the same holds for all other particles.

  10. D R Lunsford says:

    The Higgs will never be seen, see the work of Afsar Abbas.


  11. Quantoken says:

    The problem is obviously the standard model fails to predict and tell us how a Higgs boson should look like or how much its mass is, or we would not be guessing here. If the standard model is unable to confine the value of Higgs mass, then that means its mass really doesn’t affect anything in the model. Then what will happen if you exptrapolate that mass to realy big or real small scale?

    There are certainly two possibilities that Higgs may or may not exist. Within the case it does exist, we can also list a number of possibilities.

    One, its energy is totally within reacheable range of today’s running accelerators, but the cross-section is just too small to be detectable.

    Two, it’s energy is many order’s higher than reacheable level, and even approach Planck mass scale. Then it’s beyond the technology in the near future to detect it.

    In the case Higgs does not exist, there are also several possibilities:

    One, physicists will just continue to search at higher and higher energy for Higgs particle, until they reach the Planck mass, at which point a wormhole occurs and physicists enter into another universe through the wormhole and continue searching for Higgs, because they simply can not believe that the standard model is wrong.

    Two, at certain energy level they detected something. Because of their eagerness to find Higgs, they call it Higgs boson. But it’s actually not the Higgs boson they look for.

    Three, the third possibility does not exist, go back to possibility one above and search at higher energy.

    I think the odd that LHC exactly provides the right scale of energy, not too high and not too low, for detecting Higgs, and that the cross-section is big enough for detection. Is going to be very low.

    I do not know why some one worries about LHC creating blackholes? You need at least one Planck mass to create the smallest possible blackhole. LHC is many orders below that.


  12. Anonymous says:

    Ah, we already know that the Standard Model is correct, so discovery of the Higgs is “trivial”. Seeing our first fundamental scalar is trivial. Why even waste money on this?

    The corollary is that the most interesting result will be if the Higgs fails to show up at all.

  13. Anonymous says:

    Isn’t there a non-zero probability that the creation of a Higgs boson will create a black hole that will swallow up the Earth?

    If so, then the discovery of the Higgs truly will be only a few-day celebration as Lubos desires.

  14. Anonymous says:

    not really. There are Higgsless models around

  15. Luboš Motl says:

    My personal preferred guess (30%) is that the Higgs is at the 115 GeV level, and it’s one of the light Higgs scenarios that are natural in SUSY.

    But the discovery of Higgs will be a few-day celebration only. It’s a trivial thing. We know that something like the Higgs must be there to make the WW WW scattering unitary, and the fundamental scalar is simply preferred by precision measurements.

    The real question to answer is SUSY below TeV, and other potential new physics.

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