# Measurements of four-lepton production in $pp$ collisions at $\sqrt{s}=$ 8 TeV with the ATLAS detector

Abstract : The four-lepton ($4\ell$, $\ell = e, \mu$) production cross section is measured in the mass range from 80 to 1000 GeV using 20.3 fb$^{-1}$ of data in $pp$ collisions at $\sqrt{s}=8$ TeV collected with the ATLAS detector at the LHC. The $4\ell$ events are produced in the decays of resonant $Z$ and Higgs bosons and the non-resonant $ZZ$ continuum originating from $q\bar q$, $gg$, and $qg$ initial states. A total of 476 signal candidate events are observed with a background expectation of $26.2 \pm 3.6$ events, enabling the measurement of the integrated cross section and the differential cross section as a function of the invariant mass and transverse momentum of the four-lepton system. In the mass range above $180$ GeV, assuming the theoretical constraint on the $q\bar q$ production cross section calculated with perturbative NNLO QCD and NLO electroweak corrections, the signal strength of the gluon-fusion component relative to its leading-order prediction is determined to be $\mu_{gg}=2.4 \pm 1.0 (stat.) \pm 0.5 (syst.)\pm 0.8 (theory)$.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-01205901
Contributor : Sabine Starita <>
Submitted on : Monday, September 28, 2015 - 10:33:39 AM
Last modification on : Thursday, November 26, 2020 - 3:39:06 PM

### Citation

G. Aad, M.K. Ayoub, A. Bassalat, C. Bécot, S. Binet, et al.. Measurements of four-lepton production in $pp$ collisions at $\sqrt{s}=$ 8 TeV with the ATLAS detector. Physics Letters B, Elsevier, 2016, 753, pp.552-572. ⟨10.1016/j.physletb.2015.12.048⟩. ⟨in2p3-01205901⟩

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