HCP 2011: Will it Deliver?

The rumour mill is once again turning its rusty wheels, and there are suggestions that an interesting result will be revealed at Hadron Collider Physics conference in Paris next week. More on that in a minute.

You may think that things have been quietly lately but there have been a lot of workshops going. They have not been reported much but of course us bloggers have been trawling the slides for anything new and exciting. In case you want to search for anything we might have missed here is a convenient list of links:

One thing that turned up was an update to the Higgs -> WW analysis for ATLAS upgrading it from 1.7/fb to 2/fb, The effect is not terribly exciting, nothing has changed.
So now we are waiting for the HCP conference but not much is expected, or is it? The full schedule of talks can be found here. If this is to believed even the new update for H -> WW will not be shown. The only thing certainly new is the ATLAS+CMS combination of data shown at Lepton Photon nearly three months ago.
But then an organizer speaks of a last-minute talk being added and a comment over at NEW says “…or maybe something else violates CP at 3.5 sigma level.” So do we have a new rumour about – perhaps – a result from LHCb, or is someone just hyping the conference?
Apart from that the next big question is when will the next wave of Higgs results be revealed? They must have done more analysis at 2/fb, yet we have not had anything beyond 1/fb for the crucial diphoton search from ATLAS. I am sure they must have also looked at plots using 3/fb to 4/fb but nothing has been said, except a few vague rumours that I don’t find convincing.
Now they will be preparing the 5/fb plots that should be ready for approval in December. We may see them soon after but if the results are really so inconclusive we may have to wait for the 5/fb ATLAS+CMS combination. That means there may be nothing ready to show until Moriond in March, unless…
Rumour Update 24-Nov-2011: The rumour apparently concerns a measurement of ΔACP at 600/pb and will be shown in the last talk today at HCP11. This quantity is the difference between decays of a charmed D meson into Kaons or pions. It is not yet clear if the rumoured 3.5 sigma result is merely a signal of CP violation or a deviation from the standard model.

17 Responses to HCP 2011: Will it Deliver?

  1. Why wait until march? You are our messiah!

  2. carla says:

    Isn’t it great that it’s 2011 and we’re in this position?

    A 5/fb combination from Atlas and CMS before March…mmm… I can spell the aroma of the Higgs already…

  3. Kea says:

    Perhaps an LHCb confirmation of the like sign dimuon anomaly?

  4. Cliff H says:

    I want to see what happened to those multi-lepton excesses, and I also want to see some higher jet-multiplicity data so I can see what the story is on my current favorite scenario: http://arxiv.org/abs/1108.5169

    Im sure the Higgs data will be juicy with 5 fb^-1. Im with carla. I can almost smell it…

  5. ondra says:

    Lets hope we will see something with 3 fb-1, else the conference will not deliver anything useful. Wonder what will be the fluctulation there and what twists and turns will theorist do to satisfy it :-).

  6. […] are expected with respect to this talk but DG of CERN asked for updates in the mid of December (see here for other information). Besides, rumors are spreading around blogosphere that a group at CERN asked […]

  7. Anonymous says:

    This previous entry claims that with 5/fb of data “5/fb is enough to exclude Higgs or find evidence for it up to 600 GeV”. http://blog.vixra.org/2011/07/05/for-lhc-geeks-only/

    Is the previous entry based on incorrect calculations?

    • Philip Gibbs says:

      Those numbers were based on data from some time ago and they do look to me to be a little optimistic at the extreme ends.On top of that there are further caveats to add.

      When they say they should have enough data for a 3 sigma observation or exclusion at a given mass, they mean that given average expectations for either eventuality that is what they would have. However, fluctuations are also to be expected. A one sigma fluctuation could turn your expectation of a 3 sigma signal into either a 2 sigma signal or a 4 sigma signal depending on which way it goes. At another mass you might expect a 4 sigma signal but a 2 sigma fluctuation (which is not unusual) reduces that to a 2 sigma signal which is not significant at all.

      Another thing they have to watch out for is that some channels including the dominant WW channel have big backgrounds and systematic errors from energy resolution that have been made worse by pile-up. Indications are that the WW channel will only be good for exclusion in some ranges and may have to be left out to get a clear signal at low mass. This also means that more data will be needed than earlier expectations.

      This is why they have said that they should have the answer by the end of 2012 rather than now with 5/fb. Hopefully they have given themselves enough lee-way to make good on the promise. Then again, if the mass is not in the worst case place or if they are lucky with the fluctuations it could be found sooner.

  8. […] numerical result which was already rumoured at the weekend is ΔACP = -0.82% ± 0.25% which is just over 3 sigma […]

  9. viXra log says:

    […] numerical result which was already rumoured at the weekend is ΔACP = -0.82% ± 0.25% which is just over 3 sigma […]

  10. the result gathered at LHCb on CP violation will bring new addition to the field of Particle Physics.

    Dr. Prem Raj Pushpakaran

  11. the result at LHCb on CP violation will bring new addition to the field of Particle Physics.

    Dr. Prem Raj Pushpakaran

  12. ondra says:

    So, LHC combination for 1.5-2.3 fb-1 is online and only thing we know now is that Philip did pretty good job :).
    So except LHCb result and some updates on SUSY and exotics ,which more or less, especially on exotics, pushed the limits beyond several TeV the HCP was rather disappointing.

  13. Tony Smith says:

    The LHC combination presentation at HCP11 by Gigi Rolandi
    is very disappointing to me because it contains
    very strong statements of exclusion
    apparently based on extensive (mis)use of LEE
    and NO discussion of LEE issues
    and NO presentation of results without LEE.

    Here are some statements from the presentation:

    “ZZ channel alone exclude 108 < MH < 480 GeV" (slide 19)

    "Observed exclusion 95% CL 141-476 GeV"
    when plot shows interesting 240 GeV peak at 99% CL
    and also shows non-exclusion at 220 GeV and 300 GeV at 99% CL (slide 25)


    "Conclusions: LIttle room left for the SM Higgs !
    114 < mH < 141 GeV at 95% CL"


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