LHC to be restarted next week.

[klazmon]

Towards the end of the technical stop

After several weeks of hard work, the short technical stop of the LHC accelerator is coming to an end. Following a very intense campaign to repair and retest many thousand high voltage connectors, the upgraded magnet protection system is being commissioned. During this period, the current in the main dipole and quadrupole magnets is carefully increased up to 6kA, required to collide protons at 7TeV centre-of-mass energy. This has been achieved for most of the sectors.

Source

[Dr. Kwaltz]

Beautiful!

Can't wait for the first high energy collisions and the analysis of the events.
But while we do, let's shorten the time with some Hadron Rap...

[lpetrich]

They've started sending protons into it again, though without accelerating them beyond their injection energy of 450 MeV - My Way News - Atom smasher restarts to prepare for new science

They'll be gradually increasing their protons' energy up to their target of 3.5 TeV. It's half the design energy of 7 TeV, but it should do.

The LHC is the latest step in a long road, of course, and it will help do for the Standard Model what has been done for its predecessors: chemical elements, nuclei, and hadrons.

The Standard Model of elementary particle physics looks like a big mess, but it has patterns in it, patters suggestive of some underlying theory.

Something like the chemical elements in the 19th century, atomic nuclei in the early 20th century, and hadrons in the mid 20th century.

They were successfully resolved: atoms are electrons orbiting nuclei, nuclei are blobs of protons and neutrons, and hadrons are blobs of quarks and gluons.

There have been lots of efforts to construct Grand Unified Theories and even Theories of Everything, but the Standard Model still does not constrain them that much. The LHC's most energetic predecessor, the Tevatron, was able to go up to the expected upper limit of the Standard Model, but not any further. The LHC will go further, and it should be able to detect supersymmetric counterparts of some known particles -- if they exist at accessible energies.

[piscator]

every time i hear of CERN/LHC i have to grit my teeth at some of the failings of American politics...


http://en.wikipedia.org/wiki/Supercondu ... r_Collider

i worked for over a year on the SSC project, as part of a team laying in survey control with the then-fledgling GPS system and processing it on DOS-based single baseline processors, so its failure to come to fruition hits me on a lot of levels

sure, i got paid, but that's about the only solace i can take from the effort...

[Nautilidae]

every time i hear of CERN/LHC i have to grit my teeth at some of the failings of American politics...


http://en.wikipedia.org/wiki/Supercondu ... r_Collider

i worked for over a year on the SSC project, as part of a team laying in survey control with the then-fledgling GPS system and processing it on DOS-based single baseline processors, so its failure to come to fruition hits me on a lot of levels

sure, i got paid, but that's about the only solace i can take from the effort...

If the Superconducting Supercollider had been built, we may have found massive particles like the Higgs and SUSY particles already. Perhaps we may be able to build it in the future...

[piscator]

every time i hear of CERN/LHC i have to grit my teeth at some of the failings of American politics...


http://en.wikipedia.org/wiki/Supercondu ... r_Collider

i worked for over a year on the SSC project, as part of a team laying in survey control with the then-fledgling GPS system and processing it on DOS-based single baseline processors, so its failure to come to fruition hits me on a lot of levels

sure, i got paid, but that's about the only solace i can take from the effort...

If the Superconducting Supercollider had been built, we may have found massive particles like the Higgs and SUSY particles already. Perhaps we may be able to build it in the future...

and mankind's knowledge in this area of HEP would be well ahead of where it is now

rebuilt? caulk up SSC as a major victory for the Luddites, and something of a metaphor for American science in general...

Go CERN Go!

[lpetrich]

The SSC would have been nice to build, but it was *very* expensive, so the politicians decided to spend their big-science money on the International Space Station instead.

Also factoring in was the end of the Cold War and a resulting lack of "beat the Russians" motive.

But the SSC would have gone up to 20 TeV per proton, as opposed to the LHC's 7 TeV design energy and 3.5 TeV energy in its soon-to-be-started run.

This would have been more than enough to cover the range of possible particle masses in the Minimal Supersymmetric Standard Model and similar theories. As it is, the LHC barely covers them.

The MSSM's masses are constrained by association with electroweak symmetry breaking. That is what makes the masses of the W and Z -- 80 GeV and 91 GeV. Predictions for MSSM additional particles range from around 100 GeV to as much as 1 TeV; the MSSM has several parameters in it.

The LHC may seem overdesigned, but it's not -- protons are composite, meaning that their kinetic energy will be divided among their constituent particles. This means at most about 1/4 of an accelerated proton's kinetic energy will be available for each new particle. Checking on the Particle Data Group's bounds, several of them were obtained with the Fermilab Tevatron, which accelerates protons and antiprotons up to 1 TeV. One of the highest bounds is on an extra top-like quark, about 256 GeV; most of the others are less than half that value.

1 TeV - 100 to 250 GeV
3.5 TeV - 350 to 875 GeV
7 TeV - 700 to 1750 GeV
20 TeV - 2 to 5 TeV

[lpetrich]

W00t!

My Way News - Geneva atom smasher sets record for beam energy

They've now circulated protons at 3.5 TeV of kinetic energy in both directions. They should be starting collisions in a few days, and they'll be doing collisions at that energy for the next 12 - 18 months.

They've now beaten the Fermilab Tevatron by a factor of 3.5.

[Horwood Beer-Master]

In the words of Burns' Grandfather (in a flashback scene in 'Last Exit to Springfield')...


"Come on, men! Smash those atoms!"

[owtth]

Here's a very cool live webcast of the LHC.

[Nautilidae]

Here's a very cool live webcast of the LHC.

Excellent find!

[enkidu]

Here's a very cool live webcast of the LHC.

To the lifeboats!

[Nautilidae]

Here's a very cool live webcast of the LHC.

Upon watching it long enough, I now understand that this was a joke. I now realize that I fail.

[Mung Bean]

rofl. So we're fucked then.

[owtth]

Upon watching it long enough, I now understand that this was a joke. I now realize that I fail.