Anomalous Quartic Gauge Boson Couplings at Hadron Colliders

TL;DR

The paper addresses anomalous quartic gauge-boson interactions in $\gamma\gamma W^+W^-$ and $\gamma\gamma ZZ$ using a nonlinear $SU(2)_L\times U(1)_Y$ chiral Lagrangian, reducing the new couplings to two parameters $\beta_0$ and $\beta_c$ via custodial symmetry. It enforces unitarity at high energies by introducing a form factor and evaluates hadron-collider signatures in $\gamma\gamma$ plus leptons or jets channels, deriving 95% CL bounds for Tevatron and LHC scenarios. Tevatron Run II can reach LEP-like limits on the quartic couplings, whereas the LHC can tighten these constraints by orders of magnitude, with the $pp\to jj\gamma\gamma$ (VBF) channel delivering the strongest sensitivity and yielding $|\beta_{0,c}| \lesssim 10^{-5}$ GeV$^{-2}$ for $\Lambda = 2.5$ TeV. The study demonstrates the viability of photon-pair final states to probe genuine quartic gauge couplings and underscores the importance of unitarity-preserving form factors in interpreting high-energy collider results.

Abstract

We analyze the potential of the Fermilab Tevatron and CERN Large Hadron Collider (LHC) to study anomalous quartic vector--boson interactions (photon photon Z Z) and (photon photon W+ W-). Working in the framework of SU(2)_L X U(1)_Y chiral Lagrangians, we study the production of photons pairs accompanied by (e+e-), (e nu), and jet pairs to impose bounds on these new couplings, taking into account the unitarity constraints. We compare our findings with the indirect limits coming from precision electroweak measurements as well as with presently available direct searches at LEPII. We show that the Tevatron Run II can provide limits on these quartic limits which are of the same order of magnitude as the existing bounds from LEPII searches. LHC will be able to tighten considerably the direct constraints on these possible new interactions, leading to more stringent limits than the presently available indirect ones.

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