Scattering amplitudes in open superstring theory (Q2888513)

The author focuses on the scattering amplitutes in open superstring theories for which two different formalisms are introduced to compute the level amplitudes -- the Ramond Neveu Schwarz- (RNS-) and the Pure Spinor- (PS-) formalism. Indeed, the results discussed in this review are the outcome of a detailed investigation done on a broad topic of scattering amplitudes in superstring theory such as the phenomenological aspects of a low string scale, the conformal field theory arising in the RNS superstring, higher spin scattering and scattering amplitudes in the PS-formalism. This review consists of three parts.NEWLINENEWLINEIn the first part, the author provides a summary of the basic ingredients of the RNS superstring in which the CFT machinery necessary for the computation of the scattering amplitudes in the subsequent parts is contained. The second part deals with the disk amplitudes in the context of RNS methods. Three of the author's publications [the author, Nucl. Phys., B 849, No. 2, 433--460 (2011; Zbl 1215.81116); the author and \textit{D. Härtl}, Nucl. Phys., B 849, No. 2, 364--409 (2011; Zbl 1215.81088)] concern the old problem that the RNS superstring is only superficially based on a free worldsheet theory, since fermion emission involves subtle ingredients, the so-called spin fields. By utilizing techniques from bozonization, one can compute their correlators, but at the same time by doing this the Lorentz symmetries breaks and therefore a precise translation of the results obtained in bozonized language into covariant expressions is required. This is done by the author in Section 5. In Section 8, the author reviews the research done to compute the full fledged cross section for five point disk scattering of quarks and gluons and discusses model independent features of multi-parton processes. This is indeed a continuation of research done in [90]. Moreover, the results discussed in Section 5 prove to be an essential toolkit in computing the multi parton scattering processes relevant at LHC. Part three concerns PS-formalism which allows for a manifestly supersymmetric treatment of scattering amplitudes in ten spacetime dimensions with sixteen supercharges. A family of superfields which arises in tree amplitudes of massless open string states are presented which can be naturally identified with diagrams made of cubic vertices. A compact superspace representation of multiparticle field theory amplitudes are obtained and the complete \(n\) point superstring amplitudes as a minimal linear combination of partial field theory amplitudes and hypergeometric functions are expressed. In Section 14, the author outlines several interesting and challenging future research projects which are motivated by the results explained and mentioned in this review.