My favorite quip about String Theory is that it’s a widely beautiful mathematical theory of Everything that’s still searching to make a prediction.
There was a lot of excitement a few years back when a team of theorists devised an experimental test of the theory that could be performed by energies accessible at CERN. The idea was that certain proton-proton collisions around 7 TeV should create a spray of micro black holes, according to theory.
Except it didn’t work out apparently according to this statement posted on the CERN website:
“Microscopic black holes are predicted to exist in some theoretical models that attempt to unify General Relativity and Quantum Mechanics by postulating the existence of extra ‘curled-up’ dimensions, in addition to the three familiar spatial dimensions. At the high energies of the Large Hadron Collider, such theories predict that particles may collide ‘closely enough’ to be sensitive to these postulated extra dimensions. In such a case, the colliding particles could interact gravitationally with strengths similar to those of the other three fundamental forces – the Electromagnetic, Weak and Strong interactions. The two colliding particles might then form a microscopic black hole.
If it were so produced, a microscopic black hole would evaporate immediately, producing a distinctive spray of sub-atomic particles of normal matter. These would then be observed in the high-precision CMS detector that surrounds the LHC collision point. CMS has searched for such events amongst all the proton-proton collisions recorded during the 2010 LHC running at 7 TeV centre-of-mass energy (3.5 TeV per proton beam).
No experimental evidence for microscopic black holes has been found. This non-observation rules out the existence of microscopic black holes up to a mass of 3.5–4.5 TeV for a range of theoretical models that postulate extra dimensions.”
Read the full article here.
Some folks commenting about this online are saying that this, in of itself, doesn’t disprove string theory, but it does mean that theorists have a lot of tweaking to do to it if it’s going to be taken seriously going forward.