Of Higgs, Unitarity and other Questions

TL;DR

This paper examines the assumptions behind the Standard Model, especially regarding the Higgs boson and unitarity, questioning whether a Higgsless electroweak model can maintain unitarity and discussing related theoretical issues.

Contribution

It critically analyzes a Higgsless electroweak model based on a nonlinearly realized gauge group, challenging common beliefs about the Higgs boson's role in unitarity.

Findings

The Higgsless model maintains perturbative unitarity via Slavnov-Taylor identities.

Questions the link between Higgs existence and unitarity based on Froissart bound and Equivalence Theorem.

Raises open questions about zero mass limit and longitudinal polarization behavior.

Abstract

On the verge of conclusive checks on the Standard Model by the LHC, we discuss some of the basic assumptions. The reason for this analysis stems from a recent proposal of an Electroweak Model based on a nonlinearly realized gauge group SU(2) X U(1), where, in the perturbative approximation, there is no Higgs boson. The model enjoys the Slavnov-Taylor identities and therefore the perturbative unitarity. On the other hand, it is commonly believed that the existence of the Higgs boson is entangled with the property of unitarity, when high energy processes are considered. The argument is based mostly on the Froissart bound and on the Equivalence Theorem. In this talk we briefly review some of our objections on the validity of such arguments. Some open questions are pointed out, in particular on the limit of zero mass for the vector mesons and on the fate of the longitudinal polarizations.