[Paper Review] On Singularity Structure, New RR-String Couplings in Asymmetric Picture and Their All Order $\alpha'$ Corrections

Ehsan Hatefi|arXiv (Cornell University)|Jul 9, 2015

Black Holes and Theoretical Physics37 references3 citations

TL;DR

This paper investigates four- and five-point string amplitudes involving a closed string Ramond-Ramond (RR) field and two or three transverse scalar fields in type IIA and IIB string theories, using an asymmetric picture. It derives complete S-matrix forms, identifies new RR-string couplings unique to the asymmetric picture, and computes all-order α′ higher derivative corrections, revealing distinct singularity structures and contact interactions in this formulation.

ABSTRACT

We have analyzed in detail the four and five point functions of the string theory amplitudes including a closed string Ramond-Ramond (RR) in an asymmetric picture and either two or three transverse scalar fields in both IIA and IIB. The complete forms of these S-matrices are derived and these asymmetric S-matrices are also compared with their own symmetric results where various new couplings in asymmetric picture of type II string theory are explored. All order $\alpha'$ higher derivative corrections to these new couplings have been discovered. Several remarks on two different kinds of singularity structures as well as contact interactions of the S-Matrix in an asymmetric picture have also been made.

Motivation & Objective

• To analyze the structure of string amplitudes involving Ramond-Ramond (RR) fields and transverse scalar fields in the asymmetric picture of type II string theory.
• To identify and characterize new couplings that emerge exclusively in the asymmetric picture, distinguishing them from symmetric picture results.
• To derive all-order α′ higher derivative corrections to these newly identified couplings.
• To examine the singularity structures and contact interaction terms in the S-matrix within the asymmetric picture framework.
• To compare asymmetric and symmetric picture results to clarify the role of picture changing in RR couplings and amplitude structure.

Proposed method

• Derivation of complete S-matrix amplitudes for four- and five-point functions involving one RR field and two or three transverse scalars in type IIA and IIB string theories.
• Use of the asymmetric picture formalism for RR fields, which differs from the standard symmetric picture in string field theory.
• Comparison of the asymmetric S-matrix results with their symmetric counterparts to isolate new couplings unique to the asymmetric formulation.
• Analysis of singularity structures in the S-matrix to identify poles and contact terms arising from the asymmetric picture.
• Systematic computation of all-order α′ corrections to the new couplings using the derived S-matrix forms.
• Application of string amplitude techniques to extract effective field theory couplings and their higher derivative corrections.

Experimental results

Research questions

• RQ1 What new RR-string couplings emerge specifically in the asymmetric picture of type II string theory?
• RQ2 How do the singularity structures of the S-matrix differ between the asymmetric and symmetric pictures in RR-amplitude computations?
• RQ3 What are the all-order α′ higher derivative corrections to the newly identified couplings in the asymmetric picture?
• RQ4 How do contact interactions in the S-matrix manifest in the asymmetric picture compared to the symmetric one?
• RQ5 What is the role of the picture changing operator in modifying RR couplings and amplitude structures?

Key findings

• New RR-string couplings are identified that are absent in the symmetric picture, arising exclusively from the asymmetric picture formulation.
• The complete S-matrix forms for four- and five-point amplitudes with RR and scalar fields are derived in the asymmetric picture.
• All-order α′ higher derivative corrections to the new couplings are computed, revealing their full perturbative structure.
• Two distinct types of singularity structures are found in the asymmetric picture S-matrix, indicating different physical pole behaviors.
• Contact interaction terms are explicitly identified in the S-matrix, contributing to the effective action beyond pole structures.
• The comparison between asymmetric and symmetric picture results confirms the emergence of new dynamics not visible in the symmetric formulation.