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and world leaders outside Geneva to celebrate the official LHC inauguration, which had been optimistically planned well in advance—before anyone could have predicted the disastrous events that occurred a mere few weeks before. The day was filled with speeches, music, and—as is important at any European cultural event—good food. It was enjoyable and informative even with the premature timing. Despite anxieties about the September incident, everyone was filled with hope that these experiments would shed light on some of the mysteries surrounding mass, the weakness of gravity, dark matter, and the forces of nature.

Although many CERN scientists were unhappy about the infelicitous timing of the event, I saw the celebration more as a contemplation of this triumph of international cooperation. The day’s events did not yet honor discovery but instead recognized the potential of the LHC and the enthusiasm of the many countries participating in its creation. A few of the speeches were truly encouraging and inspirational. The French prime minister, Frangois Fillon, spoke of the importance of basic research and how the world financial crisis should not impede scientific progress. The Swiss president, Pascal Couchepin, spoke of the merit of public service. Professor Jose Mariano Gago, Portugal’s minister for science, technology, and higher education, spoke about valuing science over bureaucracy and the importance of stability for creating important science projects. Many of the foreign partners visited CERN for the first time for the day’s celebration. The person seated next to me during the ceremony worked for the European Union in Geneva—but had never set foot inside CERN. Having seen it, he enthusiastically informed me of his intention to return soon with his colleagues and friends.

NOVEMBER 2009: VICTORY AT LAST

The LHC finally came back online on November 20, 2009, and this time, it was a stunning success. Not only did proton beams circulate for the first time in a year, but a few days later, they finally collided, creating sprays of particles that would enter the experiments. Lyn enthusiastically described how the LHC worked better than he had expected—a remark that I found encouraging but a bit peculiar in light of his being in charge of making the machine run as successfully as it had.

What I hadn’t understood was how much more quickly all the pieces had fallen into place than would have been anticipated based on the experience with past machines. Maurizio Pierini, a young Italian CMS experimenter, explained to me what Lyn had meant. Tests that took 25 days in the 1980s for the LEP beams of electrons and positrons in the same tunnel were now completed in less than a week. The proton beams were remarkably on target and stable. And the protons stayed in line—very few stray particles were detected. The optics worked, the stability tests worked, realignments worked. The actual beams matched precisely the computer programs that simulated what should occur.

In fact, the experimenters were taken by surprise when they were told Sunday at 5:00 P.M., only a couple of days after the renewed beams began circulation, to expect collisions the next day. They had anticipated a little bit of time between first beams after the shutdown and the first actual collisions they could record and measure. This was now to be their first opportunity to test their experiment with actual proton beams, rather than the cosmic rays they had used while waiting for the machine to run. The short notice meant, however, that they had very little time to reconfigure their computer triggers that tell computers which collisions to record. Maurizio described the anxiety they all felt, since they didn’t want to foolishly fumble this opportunity. At the Tevatron, the first test had been mangled by an unfortunate resonance of the beam circulation with the readout system. No one wanted to see this happen again. Of course, in addition to unease, an enormous amount of excitement was shared by everyone involved.

[ FIGURE 28 ] Brief outline of the LHC’s history.

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