Thursday, May 4, 2017

There Are No Black Holes In The LHC

The CMS experiment looked for black holes at the Large Hadron Collider (LHC) in a search including higher energy Run-2 data, and found none. As a result, CMS has excluded the possibility that black holes could be created by high energy particle collisions such as those produced by LHC Run-2, up to extremely high energies.
A search for new physics in energetic, high-multiplicity final states has been performed using proton-proton collision data collected with the CMS detector at a center-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 2.3 inverse femtobarns. The standard model background, dominated by multijet production, is determined exclusively from control regions in data. No statistically significant excess of events is observed
Model-independent limits on the product of the cross section and the acceptance of a new physics signal in these final states are set and further interpreted in terms of limits on the production of black holes. Semiclassical black holes and string balls with masses as high as 9.5 TeV, and quantum black holes with masses as high as 9.0 TeV are excluded by this search in the context of models with extra dimensions, thus significantly extending limits set at a center-of-mass energy of 8 TeV with the LHC Run 1 data.
CMS Collaboration, "Search for black holes in high-multiplicity final states in proton-proton collisions at sqrt(s) = 13 TeV" (May 3, 2017).

The 9.0 TeV exclusion of quantum black holes is equivalent to a 9,000,000 MeV exclusions.

By comparison, an electron is 0.511 MeV, a proton is 938.2 MeV, a neutron is 939.6 MeV, a tau lepton is about 1,776 MeV, the pole mass of a bottom quark is about 4,200 MeV, a Higgs boson is about 125,090 MeV and the pole mass of a top quark is about 174,000 MeV. 

This is the mass of a complex organic molecule, or several dozen uranium atoms.

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