Abstract

In this article we present the worldsheet integrand for one-loop amplitudes in maximally supersymmetric superstring theory involving any number n of massless open string states. The polarization dependence is organized into the same BRST invariant kinematic combinations which also govern the leading string correction to tree level amplitudes. The dimensions of the bases for both the kinematics and the associated worldsheet integrals is found to be the unsigned Stirling number S_3^{n-1} of first kind. We explain why the same combinatorial structures govern on the one hand finite one-loop amplitudes of equal helicity states in pure Yang Mills theory and on the other hand the color tensors at quadratic alpha prime order of the color dressed tree amplitude.

Highlights

  • The recursive BRST cohomology method obtained in [8] leads to compact and elegant supersymmetric answers and makes use of so-called BRST building blocks which can be regarded as superspace representatives of cubic diagrams

  • Amplitudes computed with the pure spinor formalism give rise to superspace kinematic factors in the cohomology of the BRST operator

  • That is why the zi integrals do not introduce any poles in kinematic invariants,9 i.e. that all massless open string propagators enter through the BRST invariants C1

Read more

Summary

Introduction

In recent years the pure spinor formalism [4] allowed striking compactness in the computations of scattering amplitudes both in string theory [5, 6, 39,40,41, 48,49,50, 57, 60, 61] and directly in its field-theory limit [6, 8, 17, 18, 58, 59]. The open superstring did inspire the color organization of gauge theory amplitudes and provided an elegant proof for Bern-Carrasco-Johansson (BCJ) relations among color-ordered tree amplitudes [23, 24], based on monodromy properties on the worldsheet Another difficult field theory problem which found a string-inspired answer is the explicit construction of local kinematic numerators for gauge theory tree amplitudes which satisfy all the dual Jacobi identities, see [28]. After these tree-level examples of cross-fertilization between superstring and field theory amplitudes, we hope that this work helps to provide further guidelines to organize multileg one-loop amplitudes in maximally supersymmetric SYM in both ten and four dimensions.. According to subsection 7.3, the representation (7.21) of the colordressed O(α′2) tree manifests a duality to the one-loop kinematic factor (5.34)

Review of tree-level cohomology building blocks
From vertex operators to OPE residues
From OPE residues to BRST building blocks
From BRST building blocks to Berends-Giele currents
One-loop amplitudes with the minimal pure spinor formalism
BRST building blocks for loop amplitudes
Unified notation for one-loop BRST building blocks
Diagrammatic interpretation of the loop building blocks
Berends-Giele currents for loop amplitudes
BRST-invariant kinematics for loop amplitudes
Symmetry properties of the BRST invariants
One-loop amplitudes in pure spinor superspace
Group these building blocks into Berends-Giele currents
Step 1
Step 2
Step 3: integration by parts
The closed-form n-point kinematic factor
One-loop kinematic factors built from tree-level data
KK-like identities for AF 4 and finite QCD amplitudes
BCJ-like identities for AF 4
Dual bases in color and kinematic space
Duality between one-loop integrands and MFn4
Proving total symmetry of Kn
Correspondence between color and kinematics in MFn4
Conclusions
A On the uniqueness of the b-ghost zero mode contribution
B Symmetrized traces for six- and seven-point amplitudes
C The higher-multiplicity BRST invariants

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.