Diminishing "charginos nearly degenerate with the lightest neutralino" slit using precision data

TL;DR

This paper demonstrates that precision electroweak data can indirectly exclude charginos nearly degenerate with the lightest neutralino, even when direct searches at LEP II are inconclusive.

Contribution

It provides analytical formulas for oblique electroweak corrections to exclude such charginos indirectly.

Findings

Charginos nearly degenerate with neutralinos can be excluded using precision data.

Analytical formulas for electroweak corrections are derived.

Direct LEP II searches are insufficient in this mass region.

Abstract

Though LEP II direct searches still cannot exclude a chargino nearly degenerate with the lightest neutralino if their mass is only slightly above half of the Z boson mass, it can be excluded indirectly analyzing precision data. In this particular limit simple analytical formulas for oblique electroweak radiative corrections are presented.