Search for new physics in triple boson production in proton-proton collisions at $\sqrt{s}$ = 13 TeV using the effective field theory approach

Abstract

A search for new physics in the production of three massive gauge bosons (VVV, where V is a W or Z boson) is presented. The event selection is most effective in the Lorentz-boosted regime in which all three bosons have a transverse momentum ($p_\mathrm{T}$) above 200 GeV. Standard model (SM) processes contribute few events in this regime. When a boosted W or Z boson decays hadronically, the decay products tend to form a large-radius jet with substructure that reflects the presence of two quarks from the decay; such jets are called V-tagged jets. Special techniques to reconstruct and select V-tagged jets are applied. Events are categorized according to the number and kinematic features of charged leptons and V-tagged jets. Event yields are obtained in bins of a suitable kinematic variable such as the scalar $p_\mathrm{T}$ sum of the reconstructed objects in the event. No excess over SM expectations is observed. Bounds are placed on Wilson coefficients for a set of mass dimension-6 and -8 operators in the framework of SM effective field theory. The two most stringent bounds placed by this analysis are $-$0.13 $\lt$ $c_\mathrm{W}/Λ^2$ $\lt$ 0.12 TeV$^{-2}$ and $-$0.24 $\lt$ $c_\mathrm{Hq3}/Λ^2$ $\lt$ 0.21 TeV$^{-2}$ at 95% CL, where $c_\mathrm{W}$ and $c_\mathrm{Hq3}$ are dimension-6 Wilson coefficients in the Warsaw basis and $Λ$ is the mass scale of new physics.