LHC Update

The Large hadron Collider has now entered a planned technical stop for a few days before proceeding with the last phase of proton physics runs before the long shutdown.

The amount of luminosity delivered this year at 8 TeV is now 15/fb with about 14/fb recorded in each of ATLAS and CMS. LHCb has about 1.4/fb. If this is added to last years 5/fb at 7 TeV the two big experiments now have about twice as much data for Higgs analysis than they did when they produced the discovery back in July. In the past they have given an update each time the data was doubled but now that the discovery is done they are in less of a hurry. Indications are that they will not do another update until the 2012 run  is complete. That should add another 10/fb to the total.

Before the technical stop they managed to collide protons and heavy ions for the first time. This will be used early next year to add another dimension to the study of the quark gluon plasma.

Update 22/09/2012: There is contradictory information about whether there will be an update with the current data. Dorigo had said he thought there would not be, but Incandela according to Motl says we will get an update for Hadron Collider Physics, in  Kyoto, November. Assuming the more recent news is correct this means that they will take a leisurely 8 weeks to prepare the data if they start from the technical stop (which is now ended).

18 Responses to LHC Update

  1. Robert L. Oldershaw says:

    When can we expect some diagnostic data on the spin and parity of the 125 GeV resonance?

    • Philip Gibbs says:

      I think they will have a first shot at it but significance will not be high.

      Dont expect to see the analysis until about the middle of next year at least.

  2. carla says:

    15\fb is good given the issues with beam instability, and MD. On the other hand it’s disappointing that they haven’t solved the problem with 5% losses when going into collisions.

  3. SD says:

    I just listened to a talk by a CMS member: updated results for both CMS and ATLAS in November (I don’t remember the name of the conference), and combination of ATLAS *and* CMS results for Moriond 2013!

  4. carla says:

    Hmm… I thought the few days allocated for the scrubbing was in preparation for the 25ns MD but it now seems that it’s necessary after every technical stop

    • Philip Gibbs says:

      I am not sure but I think they changed the injector MKI8 and now they find it needs scrubbing. 25ns scrubbing is still to come.

      • carla says:

        As far as I recall, they’ve always had major problems increasing intensity after a technical stop, believing that it will take only two days to recover. Invariably it always takes at least a week.

      • Philip Gibbs says:

        They always write down schedules that assume there will be no problems but that does not mean they believe there will be no problems. Notice that depsite all the things that cause holdups they always end up delivering close to their promised target.

      • carla says:

        Aha you’re right! I forgot to check the accelerator schedule which was updated – again – on 14/9/12 🙂

        Looks like they’re doing lots of 25ns development over the next two weeks which wil be fun to watch, while possibly recording over 20/fb for the year – who knows?

  5. carla, how does one “watch” the LHC.. are you at the site or something? 🙂 I mean we can read op vistars and the logbook but thats just information..

  6. ondra says:

    LHC reached yesterday 20 fb-1 delivered for 8 TeV. LHCb announced for next week seminar at CERN with new data (1,1 fb-1 at 8 TeV) for B(s)0->mu+mu- on Tuesday, November 13, 2012 from 11:00 to 12:00. Plus we expect new Higgs results, of course including tautau channel from ATLAS with 8 TeV data in Kyoto.

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