2016/10/03 by Ashoke Sen · 1 citation
Mathematics · Physics and Astronomy · #Advanced Mathematical Theories and Applications #Algebraic and Geometric Analysis #Black Holes and Theoretical Physics #Feynman diagram #Moduli #Moduli space #Perturbation theory (quantum mechanics) #Regularization (linguistics) #Scattering amplitude #Superstring theory #Unitarity #Unitary state #hep-th
paper · pdf · doi:10.1007/jhep04(2017)025
LaTeX, 12 pages
arxiv created 2016/10/03 · openalex created_date 2016/10/14 · openalex publication_date 2017/04/01 · arxiv updated 2017/04/26 · openalex updated_date 2026/08/05
Conventional superstring perturbation theory based on the world-sheet approach gives divergent results for the S-matrix whenever the total center of mass energy of the incoming particles exceeds the threshold of production of any final state consistent with conservation laws. Two systematic approaches have been suggested for dealing with this difficulty. The first one involves deforming the integration cycles over the moduli space of punctured Riemann surfaces into complexified moduli space. The second one treats the amplitude as a sum of superstring field theory Feynman diagrams and deforms the integration contours over loop energies of the Feynman diagram into the complex plane. In this paper we establish the equivalence of the two prescriptions to all orders in perturbation theory. Since the second approach is known to lead to unitary amplitudes, this establishes the consistency of the first prescription with unitarity.