We evaluate in detail the string scattering amplitude to compute different interactions of two massless scalars, one tachyon and one closed string RamondRamond field in type II super string theory. In particular we find two scalar field and two tachyon couplings to all orders of α ′ up to on-shell ambiguity.We then obtain the momentum expansion of this amplitude and apply this infinite number of couplings to actually check that the infinite number of tachyon poles of S-matrix element of this amplitude for the p = n case (where p is the spatial dimension of a D p -brane and n is the rank of a Ramond-Ramond field strength ) to all orders of α ′ is precisely equal to the infinite number of tachyon poles of the field theory. In addition to confirming the couplings of closed string Ramond-Ramond field to the world-volume gauge field and scalar fields including commutators, we also propose an extension of the Wess-Zumino action which naturally reproduces these new couplings in field theory such that they could be confirmed with direct S-matrix computations. Finally we show that the infinite number of massless poles and contact terms of this amplitude for the p = n + 1 case can be reproduced by Chern-Simons, higher derivative corrections of the Wess-Zumino and symmetrized trace tachyon DBI actions.

We calculate in detail the disk level S-matrix element of one Ramond-Ramond field and three gauge field vertex operators in the world volume of BPS branes, to find four gauge field couplings to all orders of α ′ up to on-shell ambiguity. Then using these infinite couplings we find that the massless pole of the field theory amplitude is exactly equal to the massless pole S-matrix element of this amplitude for the p = n case to all orders of α ′ . Finally we show that the infinite massless poles and the contact terms of this amplitude for the p = n + 2 case can be reproduced by the Born-Infeld action and the Wess-Zumino actions, and by their higher derivative corrections.

We calculate the disk level S-matrix element of one closed string RR field, two open string tachyons and one gauge field in type II superstring theory. An expansion for the S-matrix element has been found that its four leading order terms are reproduced exactly by the symmetric trace tachyon DBI and the Wess-Zumino actions of D-brane-anti-D-brane systems. Using this consistency, we have also found the first higher derivative correction to the some of the WZ terms.

In our continued efforts of matching full string computations with the corresponding effective field theory computations, we evaluate string theory correlators in closed forms. In particular, we consider a correlator between three SYM vertex operators and one Ramond-Ramond $C$-field vertex operator: $$. We show that the infinite number of massless poles of this amplitude can be reproduced by the Born-Infeld action, the Wess-Zumino terms, and their higher derivative corrections. More specifically we find, up to an on-shell ambiguity, two scalar field and two gauge field couplings to all orders in $\alpha'$ such that the infinite number of massless poles of the field theory amplitude exactly match the infinite number of massless poles of S-matrix elements of $$. We comment on close intertwinedness of an open string and a closed string that must be behind the matching.Comment: 23 pages, no figure, some references added and the version appears in PR

We propose a new Kaluza-Klein reduction scheme based on ADM decomposition. The scheme has been motivated by AdS/CFT, especially by how the worldvolume theory should appear from the supergravity side. We apply the scheme to IIB supergravity reduced on a 5D hyperboloidal H 5 space, and show that an (A)dS "braneworld" is be realized after further reduction to 4D. We comment on applications to cosmology and black hole physics. In particular, the scheme should provide a proper paradigm for black hole physics.