Re: Large Electron Positron Collider

From: EjP (nospam_at_hackers.are.bad)
Date: 01/18/05 

Date: Tue, 18 Jan 2005 15:09:29 -0600

DavidBowman wrote:
>>>From the gusiness world record site.
>
> Does anyone know why in the world they dismantled this device? That's
> the dumbest idea since shutting down hubble.
>

Actually it represented a very wise decision.

Remember that particle physics is a statistical science. To first
order, precision increases as sqrt(N), where N is the number of
events observed. The rough rule of thumb is that a meaningful
extention to an experiment is one that *doubles* the statistics.
LEP spent most of its life at the Z0 resonance. After they ran
out of ideas to increase the luminosity, it would have taken
many years to double the statistics they already had, so they
decided to increase the energy. They got to a little over
200 GeV center of mass energy by literally filling every
available space in tunnel with RF. This energy allowed them to
probe the W+W- production threshold, which had very specific
physics interest, and to extend the reach for Higgs and
some Supersymmetric studies. Again, once they had done these
things, they would have had to run for years more to make
very marginal improvements in the sensitivity.

It was seen as a much better bet to shut down LEP, so they
could use the tunnel to move ahead with the LHC.

-E

> =[ d
>
> The world's largest scientific instrument (and arguably the world's
> largest machine) is the Large Electron Positron Collider. It is a
> circular tube 3.8 m (12 ft 6 in) in diameter and 27 km (17 miles) in
> circumference. It is situated in a giant donut-shaped tunnel 100 m (330
> ft) below the area around the Swiss-French border in Geneva. The
> machine began operating in 1989 and was officially closed down at 8 am
> on November 2, 2000.
>

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