Unstoppable brane-flux decay of overline{mathrm{D}6} branes

Abstract

We investigate p overline{mathrm{D}6} branes inside a flux throat that carries K × M D6 charges with K the 3-form flux quantum and M the Romans mass. In such a setup brane-flux annihilation can proceed through the nucleation of KK5 branes. We find that within the calculable supergravity regime where gsp is large, the overline{mathrm{D}6} branes annihilate immediately against the fluxes despite the existence of a metastable state at small p/M in the probe approximation. The crucial property that causes this naive conflict with effective field theory is a singularity in the 3-form flux, which we cut off at string scale. Our result explains the absence of regular solutions at finite temperature and suggests there should be a smooth time-dependent solution. We also discuss the qualitative differences between overline{mathrm{D}6} branes and overline{mathrm{D}3} branes, which makes it a priori not obvious to conclude the same instability for overline{mathrm{D}3} branes.