Highly symmetric D-brane-anti-D-brane effective actions

Abstract

The entire S-matrix elements of four, five and six point functions of D-braneanti D-brane system are explored. To deal with symmetries of string amplitudes as well as their all order α corrections we first address a four point function of one closed string Ramond-Ramond (RR) and two real tachyons on the world volume of brane-anti brane system. We then focus on symmetries of string theory as well as universal tachyon expansion to achieve both string and effective field theory of an RR and three tachyons where the complete algebraic analysis for the whole S-matrix < V C −1 V T −1 V T 0 V T 0 > was also revealed. Lastly, we employ all the conformal field theory techniques toworking out with symmetries of theory and find out the expansion for the amplitude to be able to precisely discover all order singularity structures of D-brane-anti-D-brane effective actions of string theory. Various remarks about the so called generalized Veneziano amplitude and new string couplings are elaborated as well.

All order α′ corrections to fermionic couplings of D-brane-Anti-D-brane effective actions

“…Chern-Simons couplings of D-brane Anti D-brane system for general D pDp of type II are explored in section 2 of [10]. Given above information, we are now ready to write down the lower order action that describes interactions between fermions and tachyons.…”

“…In order to explore all the singularity structures, one needs to expand out the amplitude. Having set out the remarks given in [10], we would highlight some further points that are relevant to the expansion of the fermionic amplitudes. Taking momentum conservation along the world volume of brane, one gets to derive…”

“…which should be at the same order of the kinetic term of fermions. 10 Now we can write down all possible couplings of two fermions two tachyons at first order in α ′ as follows…”

“…One finds out that the whole amplitude has non-vanishing contributions for C p−3 , C p−1 , C p+1 cases. As has been argued in [10] one can immediately explore the algebraic solutions for the entire integrals in the soft limit where they get decoupled. 8 Basically the whole integrals are appeared in [47] and [48] so one can write down the final answer of the amplitude in terms of the Gamma functions.…”

On non-BPS effective actions of string theory

“…The precise form of the solutions for integrals of six point functions is unknown. Given the exact symmetries of the amplitudes and the universal tachyon expansion in [42], we were able to obtain all the singularity structures of the amplitude of a closed string RR and four tachyons. We hope to overcome some other open questions in the near future.…”