PUB - Publikationen an der Universität Bielefeld

The anomalous lack of large angle temperature correlations has been asurprising feature of the CMB since first observed by COBE-DMR and subsequentlyconfirmed and strengthened by WMAP. This anomaly may point to the need formodifications of the standard model of cosmology or may show that our Universeis a rare statistical fluctuation within that model. Further observations ofthe temperature auto-correlation function will not elucidate the issue;sufficiently high precision statistical observations already exist. Instead,alternative probes are required. In this work we explore the expectations forforthcoming polarisation observations. We define a prescription to test thehypothesis that the large-angle CMB temperature perturbations in our Universerepresent a rare statistical fluctuation within the standard cosmologicalmodel. These tests are based on the temperature-Q Stokes parameter correlation.Unfortunately these tests cannot be expected to be definitive. However, we doshow that if this TQ-correlation is observed to be sufficiently large over anappropriately chosen angular range, then the hypothesis can be rejected at ahigh confidence level. We quantify these statements and optimise the statisticswe have constructed to apply to the anticipated data. We find that we canconstruct a statistic that has a 25 per cent chance of excluding the hypothesisthat we live in a rare realisation of LCDM at the 99.9 per cent confidencelevel.