LHC Prepares for ICHEP

According to an earlier commenter on this blog, today is the cut-off date for the LHC to collect data for the ICHEP conference.  Despite technical issues,  overall the LHC has been “enjoying remarkable availability” Right on cue the luminosity delivered has passed the 5/fb mark promised by the operations group. The total LHC delivered luminosity is now about 11.2/fb for CMS and will soon pass the 11.87/fb total for the Tevatron run II.

Now the computer grid will light up as ATLAS and CMS push through the analysis for the Higgs and SUSY plots in time to get them approved for the massive ICHEP conference in one months time.

The schedule of talks  shows that each experiment will be giving detailed talks for each individual Higgs channel (plus possibly a new H -> Z+γ analysis) using 2012 data at 8 TeV leading up to the final combinations for each experiment. They will leave it up to bloggers to complete the full combination. It is likely that they will fall just short of discovery significance in diphoton channels and combined plots for each experiment. The full combined significance for the LHC will probably pass the 5 sigma finish line but no official combination will show that. This is not certain because the statistical fluctuations are not predictable.

In the lead up to ICHEP there have been many lesser HEP conferences already but none have had data beyond 2011 available from the LHC. Even at this late stage ATLAS has added a new conference note with an update to the WW channel using multivariate analysis which improves the sensitivity from 2011 data. There have been a few interesting talks about the significance of the Higgs excess at 125 GeV and some comments about the fact that the diphoton channels are showing a stronger signal than expected while the WW channel is noticeably deficient. These irregularities are likely to be statistical but they are a sign of the interesting speculations that will follow further results.

Some questions we will be looking to answer:

  • How much will the excesses seen in 2011 data be strengthened?
  • Will the CMS and ATLAS peaks still be at slightly different masses?
  • Will the channel branching ratios remain significantly different from standard model predictions?
  • Will the 115GeV to 120 GeV window be excluded?
  • Will the DG continue to call the observations just “interesting fluctuations” and get away with it?

On a slightly different topic, the 3quarksdaily blog has launched its science blog competition for 2012 which will be judged by fellow blogger Sean Carroll. About a hundred shameless bloggers have nominated themselves for the title and voting will begin for the final cut in the next couple of days. I have nominated my coverage of the December Higgs announcement so please support viXra by voting in our favour. Update: link for voting is here

21 Responses to LHC Prepares for ICHEP

  1. Tony Smith says:

    Peter Woit’s blog already says:
    “… Whatever Tommaso says about CMS blinding its data, either that’s not the case at ATLAS, or some of it is now unblinded. I [Peter Woit] hear that the first chunk of gamma-gamma data is showing some signs (2 sigma) of a signal at about the same place as last year’s data. Analysis of more data is proceeding, and very soon people at ATLAS will know whether there’s a signal there. …”.

    Is that a plausible rumour ?


    • Philip Gibbs says:

      Without knowing how much data the runour is based on it tells us almost nothing so I am not very interested.

  2. I have heard that CMS and ATLAS will not present any 8 TeV Higgs data at ICHEP, since they will probably not be able to claim 5 sigma discovery for each individual experiment.

    • Philip Gibbs says:

      The abstracts for the talks say that they will present data at 8 TeV. They have changed their plans before though.

    • carla says:

      I find that hard to believe. The whole world is eagerly awaiting to see if a data set around that of last year’s has produced the bumps in the same approx place at ICHEP which will have huge coverage. The next milestone will be to see the bumps increase over the months, concluding with both experiments making a 5-sigma discovery at the end of the year, and the uncorking of champagne.

    • ondra says:

      If CMS and ATLAS dont plan to release any 8 TeV Higgs data at ICHEP they should cancel the conference :).
      Btw they of course knew that each experiment wont be able to claim 5 sigma, because they dont want to combine 7 and 8 TeV data and they need around 15/fb in 8 TeV for claiming Higgs independently.

  3. Tony Smith says:

    Since AllanachReloaded is a professor at Cambridge working on the LHC, I would take his rumor seriously.

    I agree with Carla that it is hard to believe that
    “… CMS and ATLAS will not present any 8 TeV Higgs data at ICHEP …”
    because as Carla says
    “… The whole world is eagerly awaiting to see if a data set around that of last year’s has produced the bumps in the same approx place at ICHEP …”.

    The only reason that I can see for not presenting 2012 8 TeV data
    at ICHEP would be
    that early looks at 2012 digamma data see bumps that do NOT match up with the 2011 bumps
    in which case
    presentation at ICHEP would be an inconclusive mess
    maybe the LHC people would rather just push on for the rest of 2012 and hope to get 20/fb at the end of the year
    and also hope that some sort of consistent bumps might emerge by then.

    As Matt Strassler said on his blog, about how much data the LHC would need to find a Standard Model single Higgs at 125 GeV:

    “The expected 20 inverse fb at 8 TeV of energy should just be enough for the decays to two photons and to two lepton-antilepton pairs together to do the job, with the other decay modes as important supporting evidence. Of course, if there is a particle at 125 GeV that is NOT a “Standard Model Higgs”, then all bets are off, because the decay rates to the various processes are likely to be altered compared to Standard Model expectations. No way to guess what will happen in that case; there are too many possibilities.”


  4. wl59 says:

    According to my opinion, f.ex. stated here: http://blog.vixra.org/2011/12/13/the-higgs-boson-live-from-cern/ , from the 2011 data we had no significant indication for a Higgs.

    Specially, in the gammagamma channel, first there were several peaks at different mass values, so that there may be any instrumental or physical effect what produces such peaks, and second, worser even, at the side of the peaks were valleys or deficiences (expressed in the probabilities what the most plots show, a higher exclusion probability because of a lack of events), but the sum or integral of peeks + valleys was essentially like the expected backgrounds, what means that there were not produced additional photons (es we expect for a Higgs) but just background photons were frequence-shifted (or in terms of the mass ./. excl. prob. plots, ‘mass-shifted’). For this it’s nor necessary to observe, too, that at end of the year the data for atlas and cms shows the peak on almost mutually excluding mass values. So, I think that the gammagamma results may be affected by anything else what’s not Higgs. We should observe that ‘almost anything’ may produce photons, or even more easy, frequence-shift them slightly so that such peaks and valleys appear. I ask, why the cern people didn’t calculate the sum or integral about the whole interval, and compare it with the integral of the background, in order to calculate how many photons were effectively produced, instead of to look only to the peaks but ignore the valeys.

  5. Tony Smith says:

    The abstracts for the ATLAS Track 1 Parallel Sessions at ICHEP say:

    “… A search for the Standard Model Higgs boson in the diphoton decay channel … over the diphoton mass range 110-150 GeV is reported. Upper limits on the cross-section times branching ratio are derived. …”.

    “… A search for the Standard Model Higgs boson in the decay channel H -> ZZ* -> l+l-l+l- where l= (e, mu) is performed … Upper limits are derived on the cross section of a Standard Model Higgs boson with a mass between 110 GeV and 600 GeV. …”.

    So, we should see some interesting things:

    a diphoton histogram for 110 to 150 GeV whose bumps can be compared with the 2011 diphoton bumps

    a few ZZ to 4l events for 110 to 150 GeV for attempted comparison with diphoton bumps

    more (?dozens?) of ZZ to 4l events from 150 to 600 GeV that might support (or not) something around 240 GeV seen by ATLAS in 2011

    cross section upper limits that, if the 125 GeV single SM Higgs goes away, might indicate how smaller (than single SM) bumps might be combined to show that there may be multiple Higgs states the sum of whose cross sections add up to what is needed for a Higgs mechanism in the Standard Model

    We live in interesting times.


  6. ondra says:

    Well, to play the CERN PR games we want to know even if there is no Higgs, so number of sigmas is no argument.
    It would be also bad for CERN publicity not to publish any new Higgs search, after all CERN needs the money.

  7. Philip Gibbs says:

    Please vote for viXra Log on 3 Quarks Daily, here

    • wl59 says:

      No, because you always are in favor that a Higgs exist, and I’m in favor that it don’t exist

  8. gunn says:

    You shall not find any higgses because all physics event can be interpreted by well-known elementary particles — leptons, quarks , and gauge bosons:

  9. HHu says:

    Our current personal view of Big Bang particle (GOD particle) is here: http://prespacetime.com/index.php/pst/article/view/324

  10. Tony Smith says:

    Tommaso Dorigo was asked by Jonny on his blog
    “… How long will it take for the 5/fb collected now to be analyzed for Higgs signals? …”

    to which Tommaso replied (on 14 June 2012):
    “… A day.
    I will be more specific soon…”.

    Does that mean that we will hear by rumor about Higgs (or not) in the June 2012 5/fb of data without having to wait 3 weeks for ICHEP ?


    • Philip Gibbs says:

      I would be surprised if there were no rumours. I dont encourage them but will report them if anything significant emerges on other blogs. There will probably be more rumours saying they see bumps in the same places. Such rmours dont tell us much. Only full plots can reveal useful information. I would rather they appeared at the conference. Its OK to peer through the paper but its no fun to open your christmas presents early.


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