When it comes to top, no pairing is beyond belief !
In November 2015 the LHC delivered proton-proton collisions at 5.02 TeV, with CMS having being fully efficient and having managed to collect 26pb-1 of low pileup proton-proton collision data. The fraction of tt events initiated by gluon-gluon collisions grows monotonically with center-of-mass energy, rendering this new data set partially complementary to the higher energy samples. This study exploited candidate events with an electron-muon pair of opposite charge, accompanied by the presence of at least two jets (from the hadronization of the b quarks). The cross section is extracted with an event-counting experiment approach, and found in agreement with the SM expectation (CMS-PAS-TOP-16-015). The final uncertainty of the measurement was found to be almost 30%, the latter greatly dominated by the statistical precision.
The CP3 members Georgios Krintiras and Andrea Giammanco were involved in this measurement.
Reference url: https://cds.cern.ch/record/2161499/