Longevity of supersymmetric flat directions

Abstract

We examine the fate of supersymmetric flat directions. We argue that the non-perturbativedecay of the flat direction via preheating is an unlikely event. In order to address this issue,first we identify the physical degrees of freedom and their masses in the presence of a largeflat direction VEV (vacuum expectation value). We explicitly show that the (complex) flatdirection and its fermionic partner are the only light physical fields in the spectrum. If theflat direction VEV is much larger than the weak scale, and it has a rotational motion, therewill be no resonant particle production at all. The case of multiple flat directions is moreinvolved. We illustrate that in many cases of physical interest, the situation becomeseffectively the same as that of a single flat direction, or collection of independentsingle directions. In such cases preheating is not relevant. In the absence of a fastnon-perturbative decay, the flat direction survives long enough to affect thermalization insupersymmetric models as described in Allahverdi and Mazumdar (2005 Preprinthep-ph/0505050 and 2006 J. Cosmol. Astropart. Phys. JCAP10(2006)008). It can also ‘terminate’ anearly stage of non-perturbative inflaton decay as discussed in Allahverdi and Mazumdar(2006 Preprint hep-ph/0603244).