Wess-Zumino Couplings Research Articles

On WZ and RR couplings of BPS branes and their all order α ′ corrections in IIB, IIA

We compute all three and four point couplings of BPS $D_{p}$-branes for all different nonzero $p$-values on the entire world volume and transverse directions. We start finding out all four point function supersymmetric Wess-Zumino (WZ) actions of one closed string Ramond-Ramond (RR) field with two fermions, either with the same (IIB) or different chirality (IIA) as well as their all order $\alpha'$ corrections. The closed form of S-matrices of two closed string RR in both IIB, IIA, including their all order $\alpha'$ corrections have also been addressed. Our results confirm that, not only the structures of $\alpha'$ corrections but also their coefficients of IIB are quite different from their IIA ones. The S-matrix of an RR and two gauge (scalar) fields and their all order corrections in antisymmetric picture of RR have been carried out as well. Various remarks on the restricted Bianchi identities as well as all order $\alpha'$ corrections to all different supersymmetric WZ couplings in both type IIA and IIB superstring theory are also released. Lastly, different singularity structures as well as all order contact terms for all non-vanishing traces in type II have also been constructed.

More on Ramond–Ramond, SYM, WZ couplings, and their corrections in IIA

We obtain the closed form of the correlation function of one current and four spin operators (with different chiralities ) in type IIA superstring theory. The complete form of the S-matrix of one gauge , two fermions (with different chiralities) and one closed string Ramond-Ramond for all order $\alpha'$ type IIA has been explored. Moreover, we make use of a different gauge fixing to be able to find out all the closed forms of $<V_{C} V_{A}V_{\bar\psi}V_{\psi} >$ correlators. An infinite number of $t,s-$channel fermion poles of this S-matrix in the field theory of IIA is generated. Unlike the the closed form of the correlators of the same amplitude of IIB, for various $p,n$ cases in type IIA we do have different double poles in $t,(t+s+u)$ and in $s,(t+s+u)$ channels and we produced them. We also find new Wess-Zumino couplings of IIA with their third order $\alpha' $ corrections as well as a new form of higher derivative corrections (with different coefficient from its IIB one ) to SYM couplings at third order of $\alpha' $. Using them, we are able to produce a $(t+s+u)$ channel scalar pole of the $<V_{C} V_{A}V_{\bar\psi}V_{\psi} >$ amplitude for $p+2=n$ case. Finally we make some comments on $\alpha'$ corrections to IIA Superstring theory.

SYM, Chern–Simons, Wess–Zumino couplings and their higher derivative corrections in IIA superstring theory

We find the entire form of the amplitude of two fermion strings (with different chirality), a massless scalar field and one closed string Ramond-Ramond (RR) in IIA superstring theory which is different from its IIB one. We make use of a very particular gauge fixing and explore several new couplings in IIA. All infinite $u$- channel scalar poles and $t,s$- channel fermion poles are also constructed. We find new form of higher derivative corrections to two fermion two scalar couplings and show that the first simple $(s+t+u)-$ channel scalar pole for $p+2=n$ case can be obtained by having new higher derivative corrections to SYM couplings at third order of $\alpha'$. We find that the general structure and the coefficients of higher derivative corrections to two fermion two scalar couplings are completely different from the derived $\alpha'$ higher derivative corrections of type IIB.

On D-brane anti D-brane effective actions and their corrections to all orders in alpha-prime

Based on a four point function, the S-matrix elements at disk level of the scattering amplitude of one closed string Ramond-Ramond field (C) and two tachyons and one scalar field, we find out new couplings in brane anti brane effective actions for p = n, p+2 = n cases. Using the infinite corrections of the vertex of one RR, one gauge and one scalar field and applying the correct expansion, it is investigated in detail how we produce the infinite gauge poles of the amplitude for p = n case. By discovering new higher derivative corrections of two tachyon-two scalar couplings in brane anti brane systems to all orders in α′, we also obtain the infinite scalar poles in (t′+s′+u)-channel in field theory. Working with the complete form of the amplitude with the closed form of the expansion and comparing all the infinite contact terms of this amplitude, we derive several new Wess-Zumino couplings with all their infinite higher derivative corrections in the world volume of brane anti brane systems. In particular, in producing all the infinite scalar poles of < VCVϕVTVT > , one has to consider the fact that scalar's vertex operator in (-1)-picture must carry the internal σ3 Chan-Paton matrix. The symmetric trace effective action has a non-zero coupling between Dϕ(1)i and Dϕ(2)i while this coupling does not exist in ordinary trace effective action.

Shedding light on new Wess-Zumino couplings with their corrections to all orders in alpha-prime

Abstract Motivated by arXiv:1203.5553, we continue to match super string amplitudes with their own effective field theory. We carry out within full details the computations of the complete form of the amplitude of one closed string Ramond-Ramond field and three SYM vertex operators, namely one gauge field and two scalar fields in type IIB(A) super string theories. Making use of the recent two gauge and two scalar couplings to all orders of α′, we produce all the infinite gauge poles for p = n case (with n as RR field strength’s rank and p as the dimension of a D p -brane). Proceeding with direct and full S-Matrix calculations, we are able to produce even all the infinite gauge poles in u-channel for p − 2 = n case in field theory as well. New couplings for p − 2 = n case with their all order α′ corrections are discovered. In addition, we explain how to find out all the infinite scalar poles of this amplitude in s, t-channels and produce them for p + 2 = n case. By comparing all of the contact terms of this amplitude, we obtain several new couplings with their higher derivative corrections for p + 2 = n, p = n cases. These new couplings are neither inside Myers’terms nor within pull-back/Taylor expansions. Finally we comment on some related issues.

Modified star-products beyond the large-B limit

Derivative corrections to the Wess–Zumino couplings of open-string effective actions are computed at all orders in derivatives, taking the open-string metric into account. This leads to a set of deformed star-products beyond the Seiberg–Witten limit, and allows to reinterpret the couplings in terms of a deformed integration prescription along a Wilson line in the non-commutative set-up. Moreover, the recursive definition of the star-products induces deformations of U(1) non-commutative Yang–Mills theory.

A note on the torsion dependence of D-brane RR couplings

The dependence on the torsion H= db of the Wess–Zumino couplings of D-branes that are trivially embedded in space–time is studied. We show that even in this simple set-up some torsion components can be turned on, with a non-trivial effect on the RR couplings. In the special cases in which either the tangent or the normal bundle are trivial, the torsion dependence amounts to substitute the standard curvature with its generalization in the presence of torsion, in the usual couplings involving the roof genus Â.

Anomalous couplings for D-branes and O-planes

We study anomalous Wess-Zumino couplings of D-branes and O-planes in a general background and derive them from a direct string computation by factorizing in the RR channel various one-loop amplitudes. In particular, we find that O p-planes present gravitational anomalous couplings involving the Hirzebruch polynomial L̂, similarly to the roof genus  encoding D p-brane anomalous couplings. We determine, in each case, the precise dependence of these couplings on the curvature of the tangent and normal bundles.