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Timothy Martonhelyi

Publications and source records attributed to Timothy Martonhelyi.

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Heavy Vector Triplets at a Muon Collider

Heavy spin-one particles are well-motivated new physics candidates that can have their origin in weakly coupled extensions of the Standard Model gauge group or in strongly coupled Composite Higgs models. Due to the variety of production and decay modes, heavy vector triplets are a useful benchmark for the study and comparison of future colliders. Here we perform a detailed collider analysis of a variety of $2 \to 2$ and $2 \to 3$ processes at a proposed future muon collider. We focus on decays into leptons and Standard Model gauge bosons, and find that heavy vector triplets could be probed up to masses of around $12\,$TeV for almost any (perturbative) value of the coupling. We compare the direct reach of a muon collider to the LHC and to updated projections for the HL-LHC, HE-LHC and FCC-hh, and include indirect limits from future measurements of electroweak precision observables. We find that a muon collider offers projected sensitivities that are competitive with future hadron colliders, exceeding those of the HE-LHC in the scenarios considered though not reaching the projected sensitivity of the FCC-hh.

hep-ph

A Simplified Model of Heavy Vector Singlets for the LHC and Future Colliders

We study a simplified model of two colourless heavy vector resonances in the singlet representation of $SU(2)_{L}$, with zero and unit hypercharge. We discuss mixing with the Standard Model gauge bosons due to electroweak symmetry breaking, semi-analytic formulae for production at proton colliders, requirements to obey the narrow width approximation and selected low energy constraints. We show current LHC constraints and sensitivity projections for the HL-LHC, HE-LHC, SPPC and FCC-hh on the charged and neutral heavy vectors. The utility of the simplified model Lagrangian is demonstrated by matching these results onto three explicit models: a weakly coupled abelian extension of the Standard Model gauge group, a weakly coupled non-abelian extension and a strongly coupled minimal composite Higgs model. All our results are presented in terms of physical resonance masses, using expressions which are accurate even at vector masses near the electroweak scale due to a parameter inversion we derive. We discuss the importance of this inversion and point out that its effect, and the effects of electroweak symmetry breaking, can remain important up to resonance masses of several TeV. Finally, we clarify the relation between this simplified model and the Heavy Vector Triplet (HVT) model, a simplified model for heavy $SU(2)_{L}$ triplets with zero hypercharge, and provide exact and approximate matching relations.

hep-ph

The Role of Vector Boson Fusion in the Production of Heavy Vector Triplets at the LHC and HL-LHC

We clarify the role of vector boson fusion (VBF) in the production of heavy vector triplets at the LHC and the HL-LHC. We point out that the presence of VBF production leads to an unavoidable rate of Drell-Yan (DY) production and highlight the subtle interplay between the falling parton luminosities and the increasing importance of VBF production as the heavy vector mass increases. We discuss current LHC searches and HL-LHC projections in di-boson and di-lepton final states and demonstrate that VBF production outperforms DY production for resonance masses above 1 TeV in certain regions of the parameter space. We define two benchmark parameter points which provide competitive production rates in vector boson fusion.

hep-ph