In just three weeks time ICHEP 2012 will be underway with the biggest expected news to come from Higgs Searches presented on 9th July in Melbourne. Meanwhile closer to home a much more low-key meeting at CERN has given us an update on the running of the LHC. As far as I can tell from the images of the auditorium the only people who attend these meetings in person are the speakers, but there are high quality webcasts so nobody else has to.
The usual LHC Machine Status Report by Steve Myers is worth watching if you are interested in where they stand with beam operations. Tonight they will have a celebration for collecting 5/fb although they have already passed the 6/fb mark. This merged slide shows progress as we approach the next technical stop compared to his prediction from Chamonix. It is good news that they are almost on target and will decide not to use the two months of extra running that had been set aside just in case. They will need the extra time to do the growing pile of tasks scheduled for the long shutdown which could easily extend to nearly two years long if they are not careful. If you are observant you will also notice that the main goal is illustrated with a picture I took for this blog last year but Myres will have to nick a lot more of my stuff if he is to get even for all the ones I took from him🙂
Myers also reported a scary story about a situation that nearly led to LHC armagedon last week when they discovered in testing that the beam dump system relied on a power supply that formed a single point of failure. A simple fault could have led to a situation where the beams could not be dumped even when a failure signal would normally abort the run. The beams would have kept circulating like an unstoppable train with the only possible outcome being the loss of 120 MJ of beam energy around the accelerator ring with the potential to destroy almost anything and everything in the collider.
The progress talk from ATLAS is also interesting in that they revealed three new versions of Higgs plots using 2011 data with improved analysis methods. From this I deduce that at ICHEP they will update only the critical digamma and Z to 4l channels with 2012 data and will use these new versions of the 2011 data for some of the other channels. These will be combined to form the new ATLAS plot. Although the cut-off for collecting data for ICHEP has passed I think there is a good chance they will continue collecting up to the technical stop because the collection rate is now very high. This may give them close to 6/fb of data in the two high-resolution channels.
In the ICHEP abstracts CMS indicate that they will update all their channels with 2012 data. This difference between the two experiments is similar to what was presented at the December council meeting. As far as I know there is no technical reason why the two experiments should not combine all the 2011 data and 2012 data in the high-resolution channels in time for ICHEP, but this would risk arriving at the unfair situation where one of the two experiments gets the discovery level significance first. I think there is a good chance that they will compare preliminary results in the next few days and if it is clear that they can both reach the critical 5 sigma level they may go for full combinations and announce the joint discovery. Whether they can do this depends on how much data they use, how well they deal with pile-up, how well they control the background, how lucky they are with the fluctuations and even how big the cross-section is if the Higgs is seeing BSM enhancements. My prediction is that they wont quite get there this time round, however an unofficial discovery using ATLAS+CMS is much more likely.
Apart from these Higgs results there will be a lot of other new results presented at ICHEP including a few exotic searches (such as heavy gauge bosons) using 2012 data from both ATLAS and CMS. I expect ATLAS to hold their 2012 supersymmetry searches back for SUSY 2012 in August but the abstracts from CMS indicate that a few new SUSY at 8 TeV will be shown at ICHEP. LHCb, Tevatron and many others from the accelerator labs, neutrino experiments and astronomical observatories have the potential to produce new discoveries in particle physics and ICHEP 2012 is the place to grab the headlines so we should expect the unexpected.
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