Another staunch supporter is John Ellis, a veteran CERN theorist and professor at Kings College London, whose office at the lab displays a cardboard skeleton holding a sign implying that this is what happened to the last person who criticized “Susy,” short for supersymmetry. “Obviously I’m disappointed Susy didn’t show up when the L.H.C. was turned on,” he said, adding that there were still plenty of chances for it to show up.

Guido Tonelli, a professor at the University of Pisa in Italy who was one of the leaders of the Higgs hunt, said, “For a while we thought we could discover the Higgs and new physics at the same time — that was very exciting.” But he said he did not share his colleagues’ depression that it did not happen: “The fact that the Higgs fits the Standard Model means new physics is farther up the energy scale. We know it is there, we just don’t know if it is tomorrow or the next decade.”

He added, “We need to explore; don’t be timid.”

By the end of 2018, the collider will have logged some 15,000 trillion collisions. If something does not show up by then, Dr. Giudice said, it will be time to go back to the drawing board.

“It’s a high point of research when we have confusion,” he said. “Certainly this is a moment of confusion.”

“Confusion,” he explained, “means an opportunity for new ideas.”

Among the other ideas, Dr. Giudice suggested with a few quick squiggles and scrawls on this blackboard, is that the Higgs mass is fixed not by some deep symmetry principle, but rather by the continuing dynamics of fields and forces. As the universe expands and evolves during the Big Bang, the Higgs field, of which the boson is an expression, undergoes phase transitions, like water turning to ice. At some point, it gets stuck.

“What fixes the value of the Higgs is the history of the universe,” he said. But that would make the Higgs field unstable over very long time frames — much longer than the age of the universe — and could eventually collapse, dissolving what we think of as reality.

Another possibility, which is anathema to many card-carrying Einsteinians, is that these problematic numbers are due to random chance. There are virtually an infinite number of possible universes with different Higgs masses, but only one that has the capability of a evolving into stars, planets, us.