The CMS experiment at CERN's Large Hadron Collider (LHC) has completed a search for microscopic black holes produced in high-energy proton-proton collisions and came up empty. No evidence for their production was found and their production has been excluded up to a black hole mass of 3.5-4.5 TeV (1012 electron volts) in a variety of theoretical models.
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 dimensionsmwhen 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.
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.
Casey Kazan via CERN