Model-independent Probe of anomalous heavy neutral Higgs bosons at the LHC

TL;DR

This paper develops a model-independent framework to probe heavy neutral Higgs bosons at the LHC, analyzing their interactions, constraints, and potential signals in various processes, with a focus on measuring anomalous couplings.

Contribution

It formulates a general effective Lagrangian for heavy Higgs interactions, explores constraints, and proposes experimental signatures and observables for detection and coupling measurement at the LHC.

Findings

Heavy Higgs boson can be discovered via invariant mass peaks in specific processes.

Certain processes like VV scattering and pp to VH* are sensitive for Higgs detection.

Proposed observables can measure anomalous coupling constants experimentally.

Abstract

We first formulate, in the framework of effective Lagrangian, the general form of the effective interactions of the lightest Higgs boson h and a heavier neutral Higgs boson H in a multi-Higgs system taking account of Higgs mixing effect. We regard h as the discovered Higgs boson which has been shown to be consistent with the standard model (SM) Higgs boson. The obtained effective interactions contain extra parameters reflecting the Higgs mixing effect. Next, We study the constraints on the anomalous coupling constants of H from both the requirement of the unitarity of the S matrix and the exclusion bounds on the SM Higgs boson obtained from the experimental data at the 7--8 TeV LHC. From this we obtain the available range of the anomalous coupling constants of H, with which H is not excluded by the yet known theoretical and experimental constraints. We then study the signatures of H at the 14 TeV LHC. In this paper, we suggest taking weak-boson scattering and pp to VH* to VVV as sensitive processes for probing H model independently at the 14 TeV LHC. We take several examples with the anomalous HVV coupling constants in the available ranges to do the numerical study. a full tree-level calculation at the hadron level is given with signals and backgrounds carefully calculated. We impose a series of proper kinematic cuts to effectively suppress the backgrounds. It is shown that, in both the VV scattering and the pp to VH* to VVV processes, H boson can be discovered from the invariant mass distributions of the final state particles with reasonable integrated luminosity. Especially, in the pp to VH* to VVV process, the invariant mass distribution of the final state jets can show a clear resonance peak of H. Finally, we propose several physical observables from which the values of the anomalous coupling constants f_W and f_{WW} can be measured experimentally.