Higgs Pseudo-Observables, Second Riemann Sheet and All That

TL;DR

This paper revises the connection between Higgs pseudo-observables and physical measurements at colliders using the Higgs complex pole on the second Riemann sheet, addressing higher-order corrections and complex mass continuations.

Contribution

It introduces a comprehensive framework for defining Higgs pseudo-observables via the complex pole, including higher-order corrections and complex mass analytical continuation methods.

Findings

Numerical results for Higgs decay and production pseudo-observables.

Discussion on the impact for high-mass Higgs exclusion plots.

Method for analytical continuation of Feynman integrals.

Abstract

The relation between physical observables measured at LHC and Tevatron and standard model Higgs pseudo-observables (production cross section and partial decay widths) is revised by extensively using the notion of the Higgs complex pole on the second Riemann sheet of the $S $-matrix. The extension of their definition to higher orders is considered, confronting the problems that arise when QED(QCD) corrections are included in computing realistic observables. Numerical results are presented for pseudo-observables related to the standard model Higgs boson decay and production. The relevance of the result for exclusion plots of the standard model Higgs boson for high masses (up to $600 $GeV) is discussed. Furthermore, a recipe for the analytical continuation of Feynman loop integrals from real to complex internal masses and complex Mandelstam invariants is thoroughly discussed.