Radiative corrections to neutralino and chargino masses in the minimal supersymmetric model

Abstract

We determine the neutralino and chargino masses in the MSSM at one-loop. We perform a Feynman diagram calculation in the on-shell renormalization scheme, including quark/squark and lepton/slepton loops. We find generically the corrections are of order 6%. For a 20 GeV neutralino the corrections can be larger than 20%. The corrections change the region of µ, M 2 , tan β parameter space which is ruled out by LEP data. We demonstrate that, e.g., for a given µ and tan β the lower limit on the parameter M 2 can shift by 20 GeV.

DarkSUSY: computing supersymmetric dark matter properties numerically

“…These can change the neutralino masses by a few GeV up or down and are only important when there is a severe mass degeneracy of the lightest neutralinos and/or charginos. The expressions for δ 33 and δ 44 used in DarkSUSY are taken from [11,12] (the tree-level values can optionally be chosen).…”

Disrupting the one-loop renormalization group invariant M/α in supersymmetry

“…The motivation for this is that one can always match a weak scale theory including full threshold corrections to the initial conditions we gave in the examples above. In practice, this matching can become rather complicated [34,35,36] if one demands a high level of precision. However, it is important to understand the origin of the uncertainties associated with weak scale thresholds, as well as recognizing that, for example, measured (pole) masses must be translated into renormalized masses, and the corrections can be large (especially for the gluino [20,34,36]).…”

“…In practice, this matching can become rather complicated [34,35,36] if one demands a high level of precision. However, it is important to understand the origin of the uncertainties associated with weak scale thresholds, as well as recognizing that, for example, measured (pole) masses must be translated into renormalized masses, and the corrections can be large (especially for the gluino [20,34,36]). Note that we have implicitly assumed the running gaugino masses are specified in the scheme appropriate for supersymmetry, namely dimensional reduction with modified minimal subtraction (DR) [22].…”

“…However, nonzero quark masses bring additional corrections, which can only be partially taken into account using a decoupling method. Furthermore, the corrections to the weak gaugino masses are complicated due to the mixings inherent in the resultant charginos and neutralinos [34,36]. Luckily, incorporating the logarithmic corrections to the gluino mass, and incorporating approximate logarithmic corrections (neglecting mixings) in the weak gaugino masses is usually sufficient for most purposes.…”

“…Take the simplest case, the gluino mass [20,34,36]. It is easy to show that in the limit m q ≪ mg ≪ mq the logarithmic corrections scale with log m 2 q /m 2 g when the gluino (running) mass is evaluated at a scale Q = mg.…”