A New Probe of Naturalness

TL;DR

This paper proposes a new method to test the naturalness of the Higgs sector by examining how new scalar fields, introduced to solve the hierarchy problem, affect Higgs couplings measurable at future colliders.

Contribution

It introduces a novel probe of naturalness through Higgs coupling modifications caused by scalar fields that stabilize the Higgs mass, applicable even for gauge singlet fields.

Findings

Precision Higgs measurements can indirectly constrain solutions to the hierarchy problem.

New scalar contributions lead to measurable deviations in Higgs couplings.

The approach is effective at future linear colliders like the ILC.

Abstract

Any new scalar fields that perturbatively solve the hierarchy problem by stabilizing the Higgs mass also generate new contributions to the Higgs field-strength renormalization, irrespective of their gauge representation. These new contributions are physical and their magnitude can be inferred from the requirement of quadratic divergence cancellation, hence they are directly related to the resolution of the hierarchy problem. Upon canonically normalizing the Higgs field these new contributions lead to modifications of Higgs couplings which are typically great enough that the hierarchy problem and the concept of electroweak naturalness can be probed thoroughly within a precision Higgs program. Specifically, at a Linear Collider this can be achieved through precision measurements of the Higgs associated production cross-section. This would lead to indirect constraints on perturbative solutions to the hierarchy problem in the broadest sense, even if the relevant new fields are gauge singlets.