Prospects and Limits For the LHC's Capabilities To Test String Theory

StartsWithABang writes: The Large Hadron Collider has just been upgraded, and is now making the highest energy collisions of any human-made machine ever. But even at 13 TeV, what are the prospects for testing String Theory, considering that the string energy scale should be up at around 10^19 GeV or so? Surprisingly, there are a number of phenomenological consequences that should emerge, and looking at what we've seen so far, they may disfavor String Theory after all.

Comments

String Theory\0

[Greyfox]

If string theory does end up being proven, they're going to have to be careful not to overwrite the null terminator, or the universe will sigsegv.

Re:String Theory\0

[Anonymous Coward]

they were certainly created, but they occur amongst BILLIONS of other events. Part of the magic of the LHC is to ignore all of this and focus only on the interesting EXTREMELY RARE interactions.

I wish the interactions of your fingers and the shift/caps lock keys were extremely rare.

Re:One quote from the article that is nice...

[Coren22]

More energetic collisions happen in the upper atmosphere all the time when cosmic rays enter. If there was concern of black holes eating the earth, it would already have happened.

Here's some great camera footage at the LHC for you if you are really concerned:

http://www.cyriak.co.uk/lhc/lh...

Re:Which string theory?

[gstoddart]

Sure, but ... if Richard Feynmann

criticized string theory in an interview: "I don't like that they're not calculating anything," he said. "I don't like that they don't check their ideas. I don't like that for anything that disagrees with an experiment, they cook up an explanation--a fix-up to say, 'Well, it still might be true.': These words have since been much-quoted by opponents of the string-theoretic direction for particle physics.

I'll flat out admit I can't come close to understanding the voodoo which is string theory.

But that Feynman didn't either, and I've heard more recent quotes from physicists who basically say they don't know what it is either ... I feel I'm in good company.

I accept that my tiny little money brain isn't up to the task. But I'm not the only one saying "WTF?" about string theory.

TeV, GeV

[wonkey_monkey]

But even at 13 TeV, what are the prospects for testing String Theory, considering that the string energy scale should be up at around 10^19 GeV or so?

Why the switch to GeV? Stick with a prefix and call it 10^16 TeV.

a microscopic black hole won't hurt you

[ericbg05]

"The production of tiny black holes is one of the predictions. "
Man I hope they know what they are doing.

Microscopic black holes disappear quickly due to Hawking radiation. So if your goal is to destroy the earth, creating a microscopic black hole is not the way you want to go.

The bigger a black hole is, the more slowly it evaporates. So if you want your black hole to do any damage, it'll have to be more than a certain threshold size. Turns out that minimum-size black hole you'll need to destroy Earth is roughly the mass of Mt Everest.

If we take the density of such a black hole to be 3 * 10^18 kg/m^3, then our black hole will look like a ball with a radius of about 12 cm, i.e. it looks like a soccer ball.*

See here for more details.

* no idea if my density assumption is reasonable. I'm not a physicist -- I got the number from 20 seconds of googling. The volume of your black hole may vary.

...and even more inaccurate than usual

[Roger W Moore]

There are several mistakes in the article as well. Supersymmetry is not a consequence of String Theory. It was invented to explain the huge difference between the Higgs mass and the energy scale where gravity becomes important (the fine-tuning or hierarchy problem). It was only after its invention that String Theorists realized that they needed it to make their theories work. In fact it is entirely possible that Supersymmetry exists and String Theory does not whereas the reverse is far less likely so it is wrong to say that SUSY is a consequence of String Theory.

Similarly the use of String Theory to solve non-perturbative QCD is not some new, fundamental principle but is simply a result of applying the maths developed for String Theory to a different problem. Hence studying the quark-gluon plasma is, at best, a test of some of the maths developed for String Theory but really tells us nothing at all about the physics. For a simpler analogy if you demonstrate that calculus works this does not imply that Newton's Laws of Motion are correct even though calculus was co-invented by Newton so he could write down and apply his laws.