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Comment by jcims | Hacker News Reader

Complete physics moron here, is there no way to use particle/anti-particle annihilation to drive collision energy up?

Also, i think if we invested the money for a new collider into an effort to develop what we've learned so far into a useful technology that inspires the general public, the funding for the next collider would take care of itself.

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I'll drastically oversimplify here, but in a collider, the particles being collided are highly regimented. First, you have a very specific type of particle you want to move around, like a proton (and you had best hope you picked a charged particle so you and move it easily with an EM field). Second, you have a very specific direction for that particle so you can smash it against something else. Third, the energy the particle is at at the time of smashing is well-known and very high. It's all very specific.

Annihilation is too uncontrolled to help, often in terms of direction.

Accelerators are all about trying to add just a tiny bit more velocity to something already moving at 99.99% of the speed of light, in the exact direction that particle is already going in. So it is both precision and vanishing results.

It's a tricky situation.

LEP was annihilating electrons with positrons; LHC does not, as it only accelerates protons. FCC will have the option to do both: the plan includes two separate pipes in the same tunnel, one for protons, one for electrons.

This however does not increase the collision energy significantly: a single electron-positron pair has the (rest) energy of ~1MeV -- this is what is released during the annihilation, but the energies we want to go to at the next collider go up to 10TeV, so 10^7 times larger.

LHC smashes protons together, and for comparison the rest mass (energy) of a proton[1] is just shy of 1GeV.

So that's still 4 orders of magnitude below the collision energy of the LHC.

[1]: http://pdglive.lbl.gov/DataBlock.action?node=S016M&home=BXXX...

Perhaps counterintuitively, it makes little difference. At the energies we're considering, the mass-energy of the particles being collided is completely negligible. Switching to colliding protons and antiprotons does change the details of what you get out, but not the energy scales.

That's what the LEP did. It was replaced with the LHC.

Strange as it might sound, I think technology being developed for the next generation of mobile networks could be what opens up a new regime (with likely candidate theories) of high energy physics. - Terahertz beamforming for wakefield accelerators, to throw some lingo at you.

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