But until Tuesday, the only person likely to have known the whole picture was the director of CERN, the European laboratory that houses the $8 billion collider.
Williams and around 30 physicists working with him at Penn knew half the story because they have been looking through one of two windows into the world exposed by the collider. That window, named Atlas, is a doughnut-shaped detector, 80 feet in diameter, designed to detect exotic particles like the Higgs. Another team is using a similarly large and elaborate detector called CMS. Neither team has been privy to the results of the other, but now both will show their hands.
Williams, who Friday was getting ready to fly to CERN, near Geneva, said both teams recently reported results to the director, and whatever he heard persuaded him to hold a news briefing Tuesday.
Hanging over the heads of the Penn physicists is the worry that somehow the other team, operating CMS, will present stronger, more statistically significant evidence for a Higgs particle.
The physicists say one team could pull ahead through luck alone, if, say, they were blessed with more Higgs particles being made and then leaving behind more definitive tracks. This would represent the first particle to be found in over 16 years, and no one wants to be on the second team to find it.
The collider works by accelerating beams of protons, which are components of the atomic nucleus, to near the speed of light and steering them into head-on collisions.
Those collisions, which happen by the millions per second, produce concentrations of energy unlike anything that has existed since the origin of the universe.
