Where is the Higgs Boson?

The plenary sessions of EPS HEP 2011 start today and we still don’t know who will give the opening address in one hours time.  This is a good moment to review what we have seen so far about the Higgs before the Tevatron and LHC get to have their final word on Wednesday.

A few days ago I said you should hold your breath for some exciting Higgs results over the next few days, weeks or months. There was some skepticism over at Reddit but I have certainly been proved right for the first part of my prediction. The last few days have seen some spectacular results. We can now look forward to more developments for the rest of this year, but first let’s look back at what we have.

Here is a zoomed version of the CMS results showing a promising 2.5 sigma excess at 135 to 145 GeV

The ATLAS data also has an excess from around 120 GeV to 150 GeV

These plots have led to a lot of excitement from the media about hints of the Higgs at around 140 GeV, but some caution is required. The excesses are not yet very big. If we believe the theory that the Higgs Boson must exist and that it is ruled out at high mass then we should be ready to accept the observed signal. At the very least the chances are that something good is going on in the mass region for a light Higgs.

But wait, the Tevatron has better reach in this region. What does Fermilab say? For the full answer we will have to wait until Wednesday but here is my prediction for their combined plot

This chart, if correct, excludes the Higgs between 135 GeV and 185 GeV at the 90% confidence level. Above 185GeV a standard model Higgs is ruled out by precision measurements. This is consistent with the Fermilab press release that claims they have shown that the Higgs is “most likely” to be between 114 GeV and 135 GeV.

However, 90% confidence is not a very strong level and there is still an excess in the same area seen by the LHC, albiet not as striking.

So there is hope that some kind of Higgs particle is lurking in that region, but the signal is not strong. Some modified form of Higgs mechanism with multiplets may be a better fit to the data. If my predicted full combinations are correct a standard Higgs may already be all but ruled out even at low mass. A SUSY multiplet can still work but searches for MSSM signals have excluded the best parts of the SUSY spectrum. There is certainly a big conundrum here. Theorists may be sent back to the drawing board, but it is too early to say. When will we know more?

The official full LHC combination is due to be presented at Lepton-Photon 2011 in Mumbai, four weeks from now. They are not likely to show much more at that conference because it would mean starting the analysis work now with 1.5/fb recorded. A huge effort would be required again but now the holiday season is upon us and it would not be worth it for the relatively small amount of additional data. There is a slightly better chance that a reanalysis will be start in one months time when the next technical stop provides a natural break with at least another 1/fb added to today’s total collision database. We may even have to wait until the end of this year’s physics run when 5/fb will be recorded in each of ATLAS and CMS.

What if the standard model Higgs is ruled out? Can a SUSY Higgs multiplet survive? Will they be forced to search for a non-standard higher mass Higgs, or will a Higgsless symmetry breaking mechanism be required?  All I know for certain is that a lot more Higgs buzz is still to come by the end of this year.

For other bloggy opinions see The Reference Frame, A Quantum Diaries Survivor, Resonaances, Not Even Wrong, Life and PhysicsArcadianPseudofunctor, Of Particular Significance, US LHC Blog, Quantum Diaries, TDG Diary


6 Responses to Where is the Higgs Boson?

  1. “What if the standard model Higgs is ruled out? Can a SUSY Higgs multiplet survive? Will they be forced to search for a non-standard higher mass Higgs, or will a Higgsless symmetry breaking mechanism be required? All I know for certain is that a lot more Higgs buzz is still to come by the end of this year.”

    To me the answer is clear.

    *Photon ate the poor neutral Higgs just as twistorialization together with the identification of gauge bosons as bound states of massles fermion and antifermion requires.

    *Higgs is effectively replaced M_89 hadron physics for which already now exists a long list of indications (see the article at http://matpitka.blogspot.com/2011/07/victory-after-all.html ).

    *In particular, the 325 GeV resonance having no sensible identification in standard model (rho and omega mesons in M_89 hadron physics). TGD predicts the masses of both states correctly and no-one in his right mind can endlessly refuse to admit that together with the fantastic success of p-adic mass calculations carried out for already 15 years ago this is something extraordinary.

    The best thing the experimentalists can do now (and they will-sooner or later!) is to start to scan for the M_89 hadron spectrum revealing itself via the decays involving jets with masses corresponding to masses of M_89 quarks (102 GeV for u and d for instance). These events are certainly rare since the phase transition from M_107 to M_89 hadron physics is like boiling creating tiny droplets of the new phase. Situation is even more delicate if M_89 hadrons are dark in TGD sense (correspond to non-standard value of Planck constant: this could relate to the strange discrepancy between CDF and D0 and ATLAS findings concerning 145 GeV bump).

    *SUSY is replaced with TGD based SUSY: the signature is decays of particles to particle plus neutrino. Lepton or quark/gluon monojet plus missing energy is the signature. For instance, erratic interpretation could be as W’ decaying to lepton plus missing energy and already now slight surplus appears at large transverse momenta.

    I add also here the links to the postings summarizing the developments during these most exciting three days of my life.

    The longer story involving SUSY and Higgs and also some other new physics predicted by TGD is at
    http://matpitka.blogspot.com/2011/07/tension-in-particle-physics-circles-is.html .

    The summary about how Higgs story transformed to an eventual support for M_89 hadron physics is at
    http://matpitka.blogspot.com/2011/07/victory-after-all.html .

  2. Bornerdogge says:

    So? Did Miss World make the trip? :)

    • Philip Gibbs says:

      I missed the opening but they seemed to have moved very quickly to the prize winners talks, so I assume there were no other special guests :(

  3. […] Higgs sector does not look like what the standard model predicts. There are hints of something in the light mass window but it does not look like the SM Higgs. It does not have sufficient […]

  4. […] Higgs sector does not look like what the standard model predicts. There are hints of something in the light mass window but it does not look like the SM Higgs. It does not have sufficient […]

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