Exploring correlations between HEFT Higgs couplings κ V and κ2V via HH production at e + e - colliders

Abstract

In this work we explore the phenomenological implications at future e + e − colliders of assuming anomalous couplings of the Higgs boson to gauge bosons HV V and HHV V ( V = W, Z ) given by the κ-modifiers with respect to the Standard Model couplings, κ V and κ 2 V , respectively. For this study we use the Higgs Effective Field Theory (HEFT) where these two κ parameters are identified with the two most relevant effective couplings at leading order, concretely a = κ V and b = κ 2 V . Our focus is put on these two couplings and their potential correlations which we believe carry interesting information on the underlying ultraviolet theory. The particular studied process is e + e − → HHν ν¯, where the vector boson scattering subprocess WW → HH plays a central role, specially at the largest planned energy colliders. Our detailed study of this process as a function of the energy and the angular variables indicates that the produced Higgs bosons in the BSM scenarios will have in general a high transversality as compared to the SM case if κ 2V ̸= κ 2 V . In order to enhance the sensitivity to these HEFT parameters κ V and κ 2 V and their potential correlations we propose here some selected differential cross sections for the e + e − → HHν ν¯ process, where different kinematic properties of the BSM case with respect to the SM are manifested. Finally, we will focus on the dominant Higgs decays to b ¯b pairs leading to final events with 4 b-jets and missing transverse energy from the undetected neutrinos and will provide the expected accessibility to the ( κ V , κ 2 V ) effective couplings and their potential correlations. In our study we will consider the three projected energies for e + e − colliders of 500 GeV, 1000 GeV and 3000 GeV.