Influence of Anomalous VVh and VVhh on Determination of Higgs Self-coupling

Abstract

The recent discovery of a Higgs boson at LHC, while establishing the Higgs mechanism as the way of electroweak symmetry breaking, started an era of precision measurements involving the Higgs boson. In an effective Lagrangian framework, we consider the e + e − → ZHH process, at an ILC running at a centre of mass energy of 800 GeV to investigate the effect of the ZZH and ZZHH couplings on the sensitivity of HHH coupling on this process. Our results show that the sensitivity of the trilinear Higgs self couplings on this process has somewhat strong dependence on the Higgs-gauge boson couplings. Single and two parameter reach of ILC with integrated luminosity of 1000 fb −1 are obtained on the effective couplings, c 6 and c H , which are related to the HHH couplings, indicating how these limits are affected by the presence of anomalous ZZH and ZZHH couplings. The kinematic distributions studied to understand the effect of the anomalous couplings, again, show strong influence of Z-H couplings on the dependence of these distributions on HHH coupling. Similar results are indicated in the case of the process, e + e − → ννHH, considered at a centre of mass energy of 2 TeV, where the cross section is large enough. The effect of W W H and W W HH couplings on the sensitivity of HHH coupling is clearely established through our analyses of this process.

Cornering dimension-6 HV V interactions at high energy LHC: the role of event ratios

“…Many studies have considered anomalous Higgs couplings in context of future lepton colliders [39][40][41][42][43][44]. The general conclusion, based on analyses of the 8 TeV data, is that several (though not all) of the gauge invariant, dimension-6 HV V terms have been quite strongly constrained by the EW precision and LHC data (as discussed in section 3) .…”

Set of new observables in the process e+e−→ZHH

“…The numerical studies of the cos Θ distribution in the literature e.g. [8,34] actually probe the 3 coefficients, which can be obtained by integrating eq. ( 3.3) over Q 2 and cos ξ:…”

“…The expected constrains on several parameters (including parameters which affect λ H ) in an effective Lagrangian have been discussed in refs. [32][33][34][35]. Ref.…”

“…However, if one intends to determine more than one parameters at the same time as studied in refs. [32][33][34][35], measuring only the total cross section is not enough and one needs to consider other observables such as the invariant mass distribution of the 2 Higgs bosons [33,34]. The purpose of this paper is to introduce such observables in a rather different way.…”