The ATLAS and CMS experiments at CERN are taking a very cautionary position concerning a measurement that deviates slightly from what would be expected from known physics. Studying events containing two photons and assuming that these photons originate from the decay of a massive particle, both experiments see a small excess in the mass region of 750-760 GeV. The same analyses were also carried out on the data from the first LHC run and, within the statistics available, did not yield a sizable excess over the expectations from standard physics processes. With the small number of events collected so far, other properties of the events are consistent with known physics processes. Nevertheless, interest has arisen because both experiments see a similar fluctuation. However, with each experiment studying hundreds of distributions of this nature, the most probable explanation is coincidence and the experiments are being careful not to over-interpret the result. More data are needed to throw more light on this, and the experiments are anticipating a lot more in 2016.
"We presented a number of new preliminary results from the first look at the new data we collected in 2015. Given the number of results, we naturally expect to see statistical fluctuations: from our experience only additional data will tell us if these have been the first hints of some real new phenomena," said CMS spokesperson, Tiziano Camporesi.
"ATLAS has been running superbly in 2015, and it's great to show so many new results from the full 2015 proton data already before the end of the year. It is the nature of experiments that fluctuations come and go as more data are collected. Next year's run will give us a lot more analysing power to see if any hint we see in this year's data will persist," said ATLAS spokesperson, Dave Charlton.