# Tag Info

12

First of all, the scheme of the CERN accelerator complex you posted contains not only that single chain which brings the protons to the LHC, but also several other chains which are used for many lower energy experiments conducted in parallel at CERN. But let's focus on the LHC accelerator chain: why do we need several successive accelerators instead of a ...

8

The only way to produce antiprotons would be to collide some particles together and then filter out just the antiprotons (as there are no stable particles that we know of containing antiprotons). Fermilab produces the protons and antiprotons in a couple of stages. It starts with negatively ionised hydrogen and accelerates it using a Cockcroft-Walton ...

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The difference in scattering cross sections is more evident the lower the energy of collisions. Fig 41.11. At the energies of TeV the probability of new physics observations is the same for both choices of collisions. The reason is that at low energies the fact that the proton has three quarks and the anti proton three anti quarks predominates. Quark ...

5

I would add to @anna's answer that $p\bar{p}$ collider such as the Tevatron is CP symmetric. This was one of the arguments for continuing the Tevatron Experiments. To quote from the proposal Measurements that get a special advantage from the p-pbar environment. The primary example in this category is CP-violation, which strongly limits the range ...

3

Also, usually: History. Most of the machines in the LHC accelerator chain (well, besides the LINACs, who have always been mainly used as initial stages for the PS) once were cutting edge research tools. When building the next generation design, the old accelerator is already there and usually well understood, and so it is natural to include it in the design. ...

3

See arXiv:1104.3145, 1103.6035 and 1104.4127

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My NEW preference is the scalar with charge +4/3 that is being postulated as an explanation for the top-antitop asymmetry. There are some published papers pursuing this idea, such as http://arxiv.org/abs/1103.2757 or http://arxiv.org/abs/0912.0972 and a couple of mini reviews http://arxiv.org/abs/1108.3341 http://arxiv.org/abs/1107.0841. As of today I ...

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