Higgs Mass from D-Terms: a Litmus Test

TL;DR

This paper investigates supersymmetric models where non-decoupling D-terms from an extended U(1)_X gauge symmetry enhance the Higgs mass, proposing a model-independent test at the LHC through associated Z' boson searches.

Contribution

It introduces a framework linking Higgs mass enhancement via D-terms to observable Z' signals, establishing bounds from experiments and precision data to test these models.

Findings

Current LHC results do not exclude new parameter regions beyond existing constraints.

The Z' boson associated with U(1)_X can be detected within a specific mass and coupling window.

Precision electroweak data already constrain the parameter space relevant for Higgs mass enhancement.

Abstract

We explore supersymmetric theories in which the Higgs mass is boosted by the non-decoupling D-terms of an extended $U(1)_X$ gauge symmetry, defined here to be a general linear combination of hypercharge, baryon number, and lepton number. Crucially, the gauge coupling, $g_X$, is bounded from below to accommodate the Higgs mass, while the quarks and leptons are required by gauge invariance to carry non-zero charge under $U(1)_X$. This induces an irreducible rate, $\sigma$BR, for $pp \rightarrow X \rightarrow \ell\ell$ relevant to existing and future resonance searches, and gives rise to higher dimension operators that are stringently constrained by precision electroweak measurements. Combined, these bounds define a maximally allowed region in the space of observables, ($\sigma$BR, $m_X$), outside of which is excluded by naturalness and experimental limits. If natural supersymmetry utilizes non-decoupling D-terms, then the associated $X$ boson can only be observed within this window, providing a model independent `litmus test' for this broad class of scenarios at the LHC. Comparing limits, we find that current LHC results only exclude regions in parameter space which were already disfavored by precision electroweak data.