The two main LHC experiments have now recorded just about 5 inverse femtobarns each of data this year (CMS here, ATLAS here). This is the last week of the proton run, so that number will be near the total available for analysis until next spring when the next proton run gets started.
For some idea of what this means for the Higgs search, see for example Tommaso Dorigo’s discussion here of last year’s ATLAS projections about this. 5 inverse femtobarns was at the high end of what was expected, and the ATLAS projection was that this would be just barely enough to expect to be able to rule out a Higgs at 95% confidence level, all the way down to the LEP limit at 114 GeV. Of course, this expectation is statistical. If the Higgs is not there, and one is lucky (downward statistical fluctuation in number of events), then one can exclude at better than 95%. If one is unlucky (upward fluctuation), or the Higgs is really there, the 95% exclusion will not be achievable.
The LHC Higgs Combination Group has now combined the ATLAS + CMS Higgs results released at the summer conferences, and plans to release this in time for the HCP 2011 conference next month. Because of the efforts of Phil Gibbs, about all that needs to be said about the LHC-HCG plot is that it looks an awful lot like his, which is available here. An SM Higgs is excluded at 95% for masses below about 480 GeV, down to a lower limit of around 135 GeV (the data is actually very flat and close to the right value to exclude the SM from 135 GeV to 145 GeV).
The huge question of course is now whether there is a Higgs with mass between 135 GeV and the LEP limit (114 GeV). The current LHC data shows no definite sign of the Higgs, but the statistics is still too low to really say anything, especially for the lower part of the region. The crucial thing to watch now is the Higgs to gamma-gamma channel, which is the only one sensitive enough to hope to rule out or see a Higgs in the 115-125 GeV region, for the current amount of data collected. I don’t know when the experiments expect to release new data in this channel, just that their goal has been to each have some sort of result in December. Perhaps they’ll release something at HCP 2011, more likely not. The only rumor I’ve heard is from someone who has seen a recent plot of the ATLAS data for this channel, and he tells me he doesn’t see any bump in this region. But work on this data is on-going, and I have no idea what CMS is seeing or not seeing (my efforts to get Tommaso Dorigo drunk in Antwerp last month didn’t yield much).
At last month’s CERN Council meeting, there was a report submitted to the Council on “The scientific significance of the possible exclusion of the SM Higgs boson in the mass range 114-600 GeV and how it should be best communicated.” The report is based on the summer 2011 data, and it emphasizes excluding the Higgs at not just 95% (2 sigma), but at 5 sigma, something that will require (if the Higgs is not there) combining the 10 inverse femtobarns of data from each of the two Tevatron experiments and a similar amount from each of the two LHC experiments, something that won’t be possible until sometime after mid 2012.
Update: One more related item. At Berkeley starting today, ATLAS is holding an Analysis Jamboree on Higgs Searches. First two days is the good stuff, open only to ATLAS members, but the last day there will be an open session with theorists allowed.