Abstract

A measurement of the four-lepton invariant mass spectrum is made with the ATLAS detector, using an integrated luminosity of 36.1 fb−1 of proton-proton collisions at sqrt{s} = 13 TeV delivered by the Large Hadron Collider. The differential cross-section is measured for events containing two same-flavour opposite-sign lepton pairs. It exhibits a rich structure, with different mass regions dominated in the Standard Model by single Z boson production, Higgs boson production, and Z boson pair production, and non-negligible interference effects at high invariant masses. The measurement is compared with state-of-the-art Standard Model calculations, which are found to be consistent with the data. These calculations are used to interpret the data in terms of gg → ZZ → 4ℓ and Z → 4ℓ subprocesses, and to place constraints on a possible contribution from physics beyond the Standard Model.

Highlights

  • Vector-boson fusion and associated production with vector bosons or top-quark pairs

  • It exhibits a rich structure, with different mass regions dominated in the Standard Model by single Z boson production, Higgs boson production, and Z boson pair production, and nonnegligible interference effects at high invariant masses

  • The off-shell Higgs production rate may be affected by beyond-the-SM (BSM) processes involving additional heavy particles, or modifications of the Higgs couplings, even if there is no effect on on-shell Higgs boson production [4]

Read more

Summary

ATLAS detector

The ATLAS experiment [11,12,13] at the LHC is a multipurpose particle detector with a forward-backward symmetric cylindrical geometry and a near 4π coverage in solid angle.. The ATLAS experiment [11,12,13] at the LHC is a multipurpose particle detector with a forward-backward symmetric cylindrical geometry and a near 4π coverage in solid angle.1 It consists of an inner tracking detector surrounded by a thin superconducting solenoid providing a 2 T axial magnetic field, electromagnetic and hadron calorimeters, and a muon spectrometer. The MS is based on a system of precision chambers providing tracking information up to |η| = 2.7 and fast detectors for triggering in the region |η| < 2.4. This is followed by the software-based high-level trigger, which reduces the accepted event rate to 1 kHz on average depending on the data-taking conditions

Definition of fiducial cross-section
Data sample and event selection
Theoretical predictions and simulation
Unfolding for detector effects
Uncertainties
Measured distributions
Interpretations
Findings
10 Conclusion
Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call