Comparison of supersymmetric spectrum calculations and impact on the relic density constraints from WMAP -: art. no. 015003

We compare results of four public supersymmetric spectrum codes, ISAJET 7.71, SOFTSUSY 1.9, SPHENO 2.2.2 and SUSPECT 2.3 to estimate the present-day uncertainty in the calculation of the relic density of dark matter in minimal supergravity 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 beta or large m(0), discrepancies in the relic density are much larger. We also find important differences in the stau coannihilation region. We show the impact of these uncertainties on the bounds from Wilkinson Microwave Anisotropy Probe for several scenarios, concentrating on the regions of parameter space most relevant for collider phenomenology. We also discuss the case of A(0) not equal 0 and the stop coannihilation region. Moreover, we present a World Wide Web application for the online comparison of the spectrum codes.