In a few days, the floodgates will open and you’ll hear about the Higgs Boson being already found. The Holy Grail of particle physics will have been found and only CERN will need to confirm it in their press release. When CERN will deliver the promised press release, they will inevitably say that the Higgs is still far from being discovered and that they have only see a ‘statistically significant fluctuation’ about some energy range. The whole non-high energy physics world will breathe out a collective sigh and, defeated, ask ‘How much longer?’
Higgs Not Discovered!
In order to spare at least our readers from being part of this international collective gasping team, I would like to mention this: The Higgs Boson’s status on its road to being discovered hasn’t changed since the December CERN update. It hasn’t been discovered as yet!
I predict that this is the line that CERN will adopt when it gives the Higgs Boson status update during the International Conference on High Energy Physics (ICHEP) that will be held in Melbourne from the 4th of July to the 11th of July.
The Last Six Months at the LHC
But then what has changed in the last six months? Has the LHC been doing nothing?
The LHC is now operating at a new energy scale. The LHC had been colliding beams at 7 TeV energy last year, and, beginning this year, it has been colliding beams at 8 TeV energy. The good news is that they still see the 125 GeV bump in the 8 TeV data they saw in the 7 TeV data, which has been attributed to the Higgs Boson. This means that the 125 GeV bump is not some random fluctuation, but an actual particle – probably the Higgs.
Why Is It Still Not A Discovery?
However, the data collected is not enough to guarantee a discovery, not even when integrated with the 7 TeV data. The 7 TeV data had yielded a confidence level of 1.9 sigma from the CMS detector and a confidence level of 2.3 sigma from the ATLAS detector. Both numbers are far from the 5 sigma confidence level needed to guarantee a discovery. However, the coincidence of the mass range for the fluctuation in the two detectors is heartening.
As I have explained here, ‘confidence level’ is a quantitative measure which tells physicist how unlikely it is that a certain signal is a mere fluctuation. So 3 sigma means that the chances that a signal is a fluke are less than 0.13%. High Energy physics demands very high rigour at 5-sigma confidence level – that’s the doubts reducing from 0.13% to less than .00007%.
What To Expect From ICHEP
The ICHEP announcement will say that the Higgs has been seen in the same energy range – 125 to 126 GeV mass range – and that the amount of data is not enough to say that it is really there. The 8 TeV data is far too small – giving at most a 1.5 sigma confidence level and no more. Integrated with the 7 TeV data, the confidence levels for both detectors might swell up to 2.5 to 3-sigma (taking into account the look-elsewhere effect), which, though significant, is still not a discovery. Sorry for the disappointment!
The good news is that this is exactly what is to be expected. The Higgs search is expected to end by the end of this year. That is when you will REALLY get to know whether the Higgs actually exists or not.
As for ICHEP and Higgs announcements by CERN, you can rely on us for the information. We will post them as they are announced. Not before!