Modulation analysis methods for WIMP direct detection: merits and restrictions

The recent trend of proposing dark matter direct detection experiments using detector masses of the order of one ton initiated this study about its merits and restrictions for WIMP signature detection. It is shown that measurements of the modulation signature would become a sensitive method to study WIMP halo properties using detector masses of the order of one ton in case the DAMA evidence is confirmed. On the other hand, as soon as experiments improve limits by roughly one order of magnitude one will have to test signatures different from the WIMP modulation signature. This paper discusses data analysis techniques to reveal the modulation signature for WIMP direct detection experiments. A periodogram approach, adopted from astronomy, least squares and maximum likelihood techniques are applied to the problem of detecting a weak periodic signal in unevenly sampled noisy data. The systematics of WIMP modulation analysis is discussed and a comparison of evidence regions to limits for selected target materials is carried out.