The open string pair production revisited

The experimental efforts in testing the QED vacuum properties such as the Schwinger pair production in the presence of a strong electric field have so far not been successful. This raises a potential possibility regarding if the usual QED vacuum picture is a complete one. In this paper, we address this possibility by taking our own (1 + 3)-dimensional world as a visible D3 brane with a nearby (hidden) D3, placed parallel at a separation, in Type IIB superstring theory and by considering an analogous open string pair production process. This setup can be taken as a simplified version of the underlying QED resulting from the particle physics standard model constructed from the intersecting D-branes. We will use this simple setup to demonstrate that the stringy pair production rate in the weak-field limit, though as expected to equal to the corresponding QED rate from the braneworld picture, contains far more important information than the QED one and as such the future detection of the Schwinger pair production can teach us lessons about the existence of extra dimension(s) and a potential source of dark matter among other things.