Comparison of SUSY spectrum calculations and impact on the relic density constraints from WMAP

We compare results of four public supersymmetric (SUSY) spectrum codes, ISAJET7.71, SOFTSUSY1.9, SPHENO2.2.2 and SUSPECT2.3 to estimate the presentday uncertainty in the calculation of the relic density of dark matter in mSUGRA models. We find that even for mass differences of about 1% the spread in the obtained relic densities can be 10%. In difficult regions of the parameter space, such as large tan β or large m0, discrepancies in the relic density are much larger. We also find important differences in the stau co-annihilation region. We show the impact of these uncertainties on the bounds from WMAP for several scenarios, concentrating on the regions of parameter space most relevant for collider phenomenology. We also discuss the case of A0 6= 0 and the stop co-annihilation region. Moreover, we present a web application for the online comparison of the spectrum codes.