This talk is dedicated to the most recent measurements of the processes that
feature the production of a top quark pair either with an electroweak standard
model boson, or another pair of top, bottom or light quarks. For the
measurement of the production cross-section of top quark pair in association
with a photon, 19.7 fbβ1 of proton-proton collision data collected by
CMS detector at sβ = 8 TeV is used, while for four top production, ttΛ + bb, ttΛ + jj, ttΛW and ttΛZ the
data collected at sβ = 13 TeV amounting to 35.9 fbβ1, is used.
The measurement of ttΛΞ³ is performed in the fiducial phase
space corresponding to the semileptonic decay chain of the top quark pair, and
the cross section is measured relative to the inclusive top quark pair
production cross section. The fiducial cross section for this process is found
to be 127 Β± 27 (stat + syst) fb. The most recent search for the four top
quark production, that explores the same-sign dilepton final state, set the
upper observed (expected) limit to 4.6 (2.9β0.9+1.4β) times predicted
standard model cross section. The measured cross section of the top pair
production with two b quarks is found to be Ο(ttΛ + bb) = 3.9
Β± 0.6 (stat) Β± 1.3 (syst) pb in the full phase space. The measurement
of the ttΛW and ttΛZ processes combines three final
states with two same-sign, three and four leptons. The ttΛW and ttΛZ production cross sections are measured to be Ο(ttΛZ) = 1.00β0.08+0.09β(stat.)β0.10+0.12β(sys.) pb and
Ο(ttΛW) = 0.80β0.11+0.12β(stat.)β0.12+0.13β(sys.) pb with an expected (observed) significance of 4.6 (5.5) and 9.5 (9.9)
standard deviations from the background-only hypothesis.Comment: 6 pages, 5 figures, proceedings for the fifth annual conference on
Large Hadron Collider Physics , Shanghai, Chine, May 15-20, 201