Solution Geneva part 2

"The measurements of the collider must be precise, because the beams must intersect exactly. A 6 tera-electon-volt beam hitting another 6 TeV beam only 1 millimetre thick traveling within one millionth part of c is very tricky. The magnets along each point of the accelerator must be within several micrometers of accuracy. The whole ring must be perfectly circular. A ring of this diameter must compute π within 8 decimal places," Jacques said.

"And how much is the error?" asked Sam.

"Nearly 2 centimetres," said Jacques. He pointed. "We are at Myrin now, we must change to the 56 bus."

Sam nodded. The bus pulled up to the stop and they got out. Jacques continued, "As you know when we first escavated the LEP in the eighties, we were within 1 centimetre when we joined up the tubes."

Sam nodded again. "You haven't had to dump I hope?"

Jacques clucked his tongue. "Unfortunately, yes, we did. We have dumped the beam twice. These were test beams, so they were not heavy. Only 50 bunches or so."

"This was an automatic dump?" Sam asked.

The bus arrived and they boarded. They sat down further in the back where there was more room.

"Yes, it was an automatic dump. The sensors detected beam divergence and the dump plates were hit."

"This was near ATLAS?"

"No, the dump is between CMS and LHCb in octant 6."

"And the automatic systems are calibrated how?"

"We have a sensor matrix with software that is programmed to trip at certain thresholds. We can sample the metrics for a proper, stable beam at around 3 bunch-revolutions, or three-tenths of a millisecond."

"Have you accounted for the tidal effects of the earth''s crust?"

"_Mais bien sur_," said Jacques. "The moon does affect the curvature of the earth but only affects us by 1 millimetre in any case."

"Can the beam travel faster than light?"

"Many particles do," said Jacques. "Especially if they are going through the detection materials."

"These are all small effects," Sam said slowly. "We must be missing something that is even easier. It must be something larger. We are swatting at gnats when we are being stomped on by elephants. Why did you even call me?" she asked.

"I could not describe it on the phone or in email," said Jacques. "We are nearly there, let us get down from the bus. We will go into the meeting room to discuss it. Mathiason will meet us there."

"Mathiason?" cried Sam.