Searches for anomalous top quark-antiquark production are presented, based on $pp$ collisions at $\sqrt{s}=8\mathrm{TeV}$. The data, corresponding to an integrated luminosity of $19.7{\mathrm{fb}}^{-1}$, were collected with the CMS detector at the LHC. The observed $t\overline{t}$ invariant mass spectrum is found to be compatible with the standard model prediction. Limits on the production cross section times branching fraction probe, for the first time, a region of parameter space for certain models of new physics not yet constrained by precision measurements.

• Received 8 September 2013

DOI:https://doi.org/10.1103/PhysRevLett.111.211804

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© 2013 CERN, for the CMS Collaboration