Measurement of top quark–antiquark pair production in association with a W or Z boson in pp collisions at $$\sqrt{s}$$ = 8 TeV
The measurement of a cross section for the production of top quark–antiquark pairs (tt¯) in association with a vector boson V (W or Z) in proton-proton collisions at √s=8 TeV is presented. The results are based on a dataset corresponding to an integrated luminosity of 19.5 fb-1 recorded with the CMS detector at the LHC. The measurement is performed in three leptonic (e and μ) channels: a same-sign dilepton analysis targeting tt¯W events, and trilepton and four-lepton analyses designed for tt¯Z events. In the same-sign dilepton channel, the tt¯W cross section is measured as σtt¯W=170+90-80(stat)±70(syst)fb, corresponding to a significance of 1.6 standard deviations over the background-only hypothesis. Combining the trilepton and four-lepton channels, a direct measurement of the tt¯Z cross section, σtt¯Z=200+80-70(stat)+40-30(syst)fb-1, is obtained with a significance of 3.1 standard deviations. Finally, the measured cross sections are compatible with standard model predictions within their experimental uncertainties. The inclusive tt¯V process is observed with a significance of 3.7 standard deviations from the combination of all three leptonic channels.
- Research Organization:
- Univ. of California, Santa Barbara, CA (United States); Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), High Energy Physics (HEP)
- Contributing Organization:
- The CMS Collaboration; CMS Collaboration
- Grant/Contract Number:
- SC0011702; AC02-07CH11359
- OSTI ID:
- 1602556
- Alternate ID(s):
- OSTI ID: 1234838
- Report Number(s):
- FERMILAB-PUB-14-213-CMS; CERN-PH-EP-2014-136; CMS-TOP-12-036; TRN: US2104037
- Journal Information:
- European Physical Journal. C, Particles and Fields, Vol. 74, Issue 9; ISSN 1434-6044
- Publisher:
- SpringerCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Similar Records
Measurement of the ZZ production cross section and Z → ℓ+ℓ–ℓ'+ℓ'– branching fraction in pp collisions at
Measurement of the and cross sections in proton-proton collisions at with the ATLAS detector