Better Higgs-CP Tests Through Information Geometry

TL;DR

This paper uses information geometry to evaluate the potential of various LHC signatures for measuring CP violation in the Higgs sector, highlighting the need for a multi-step approach for robust evidence.

Contribution

It systematically compares the sensitivity of different LHC channels for CP violation detection using Fisher information, providing a novel analytical framework.

Findings

Weak boson fusion offers high sensitivity for CP violation.

Associated ZH production provides complementary information.

Higgs decays into four leptons have limited reach.

Abstract

Measuring the CP symmetry in the Higgs sector is one of the key tasks of the LHC and a crucial ingredient for precision studies, for example in the language of effective Lagrangians. We systematically analyze which LHC signatures offer dedicated CP measurements in the Higgs-gauge sector, and discuss the nature of the information they provide. Based on the Fisher information measure, we compare the maximal reach for CP-violating effects in weak boson fusion, associated ZH production, and Higgs decays into four leptons. We find a subtle balance between more theory-independent approaches and more powerful analysis channels, indicating that rigorous evidence for CP violation in the Higgs-gauge sector will likely require a multi-step process.