They were definitely observing a brand-new particle. At the time, though, there remained a single unconfirmed piece of the Standard Model: ATLAS and CMS had found the
Higgs boson, the final piece of the puzzle.
The photons at 750 gigaelectronvolts wouldn’t be completing any puzzle. They’d be extra pieces to the one already completed by the Higgs. “This was extremely intriguing,” Giudice says, “because it could not be explained by the Standard Model. This was absolutely clear.” The Standard Model does predict some photons summing to that energy, but nowhere near as many as ATLAS and CMS observed last year. Physicists flooded journals with papers, inventing potential new physics on the fly or adapting existing frameworks to account for the extra photons. Meanwhile, ATLAS and CMS continued to search for more data, just like they had for the Higgs.
Alas, there seems to be nothing new under the Sun. If you flip a coin enough times, you’re going to get a run of twenty “heads” in a row; if you crash enough photons, sometimes you’ll get a collection of 750 gigaelectronvolt photon pairs. The run of “heads” doesn’t necessarily mean that the coin is rigged, and the extra photons don’t necessarily mean the Standard Model is broken. There were just more of certain kinds of wreckage than are usually seen. The photons, in other words, were just a blip of particularly interesting noise. “This is pretty unfortunate,” theoretical physicist Michele Redi writes in an email, “as it would have been the greatest discovery in several decades in our field.”
