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

TL;DR

This study searches for signs of new physics in triple gauge boson production at 13 TeV using effective field theory, applying boosted object techniques, and finds no deviations from the Standard Model, setting bounds on Wilson coefficients.

Contribution

It introduces a novel analysis of triple boson production with boosted techniques and constrains effective field theory operators at the LHC.

Findings

No excess over Standard Model expectations observed.

Placed bounds on Wilson coefficients $c_W/\Lambda^2$ and $c_{Hq3}/\Lambda^2$.

Set the most stringent limits to date on these EFT parameters.

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 $\lt$ $c_\mathrm{W}/\Lambda^2$ $\lt$ 0.12 TeV$^{-2}$ and $-$0.24 $\lt$ $c_\mathrm{Hq3}/\Lambda^2$ $\lt$ 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 $\Lambda$ is the mass scale of new physics.