189 citations · 1.1k across the 22 of their papers we have counts for
22 papers
Superstring amplitudes from BCJ numerators at one loop
Yvonne Geyer, Jiachen Guo, Ricardo Monteiro +1
We find a direct map that determines moduli-space integrands for one-loop superstring amplitudes in terms of field-theory loop integrands in the BCJ form. The latter can be compute…
Massive ambitwistor-strings; twistorial models
Giulia Albonico, Yvonne Geyer, Lionel Mason
Ambitwistor-strings are chiral strings whose targets are spaces of complex massless particles, and whose correlation functions directly lead to simple, compact formulae for scatter…
The SAGEX Review on Scattering Amplitudes, Chapter 6: Ambitwistor Strings and Amplitudes from the Worldsheet
Yvonne Geyer, Lionel Mason
Starting with Witten's twistor string, chiral string theories have emerged that describe field theory amplitudes without the towers of massive states of conventional strings. These…
The SAGEX Review on Scattering Amplitudes
Gabriele Travaglini, Andreas Brandhuber, Patrick Dorey +35
This is an introduction to, and invitation to read, a series of review articles on scattering amplitudes in gauge theory, gravity, and superstring theory. Our aim is to provide an…
From Twistor-Particle Models to Massive Amplitudes
Giulia Albonico, Yvonne Geyer, Lionel Mason
In his twistor-particle programme of the 1970's, Roger Penrose introduced a representation of the massive particle phase space in terms of a pair of twistors subject to an internal…
Superstring loop amplitudes from the field theory limit
Yvonne Geyer, Ricardo Monteiro, Ricardo Stark-Muchão
We propose a procedure to determine the moduli-space integrands of loop-level superstring amplitudes for massless external states in terms of the field theory limit. We focus on th…
Ambitwistor Strings in Six and Five Dimensions
Yvonne Geyer, Lionel Mason, David Skinner
Ambitwistor strings are chiral (holomorphic) strings whose target is the space of complex null geodesics, ambitwistor space. We introduce twistor representations of ambitwistor spa…
Propagators, BCFW Recursion and New Scattering Equations at One Loop
Joseph A. Farrow, Yvonne Geyer, Arthur E. Lipstein +2
We investigate how loop-level propagators arise from tree level via a forward-limit procedure in two modern approaches to scattering amplitudes, namely the BCFW recursion relations…
Recursion and worldsheet formulae for 6d superamplitudes
Giulia Albonico, Yvonne Geyer, Lionel Mason
Recently two of the authors presented a spinorial extension of the scattering equations, the `polarized scattering equations' that incorporates spinor polarization data. These led…
Two-Loop Scattering Amplitudes: Double-Forward Limit and Colour-Kinematics Duality
Yvonne Geyer, Ricardo Monteiro, Ricardo Stark-Muchão
We propose new formulae for the two-loop n-point D-dimensional integrands of scattering amplitudes in Yang-Mills theory and gravity. The loop integrands are written as a double-for…
Supersymmetric S-matrices from the worldsheet in 10 and 11d
Yvonne Geyer, Lionel Mason
We obtain compact formulae for tree super-amplitudes for 10 and 11-dimensional supergravity and 10-dimensional supersymmetric Yang-Mills and Born-Infeld. These are based on the \em…
The polarized scattering equations for 6d superamplitudes
Yvonne Geyer, Lionel Mason
We introduce a spinorial version of the scattering equations, the \emph{polarized scattering equations}, that incorporates spinor polarization data. They lead to new formulae for t…
Two-Loop Scattering Amplitudes from Ambitwistor Strings: from Genus Two to the Nodal Riemann Sphere
Yvonne Geyer, Ricardo Monteiro
We derive from ambitwistor strings new formulae for two-loop scattering amplitudes in supergravity and super-Yang-Mills theory, with any number of particles. We start by constructi…
Gluons and gravitons at one loop from ambitwistor strings
Yvonne Geyer, Ricardo Monteiro
We present new and explicit formulae for the one-loop integrands of scattering amplitudes in non-supersymmetric gauge theory and gravity, valid for any number of particles. The res…
Ambitwistor Strings: Worldsheet Approaches to perturbative Quantum Field Theories
Yvonne Geyer
Tree-level scattering amplitudes in massless theories not only exhibit a simplicity entirely unexpected from Feynman diagrams, but also an underlying structure remarkably reminisce…
Two-Loop Scattering Amplitudes from the Riemann Sphere
Yvonne Geyer, Lionel Mason, Ricardo Monteiro +1
The scattering equations give striking formulae for massless scattering amplitudes at tree level and, as shown recently, at one loop. The progress at loop level was based on ambitw…
One-loop amplitudes on the Riemann sphere
Yvonne Geyer, Lionel Mason, Ricardo Monteiro +1
The scattering equations provide a powerful framework for the study of scattering amplitudes in a variety of theories. Their derivation from ambitwistor string theory led to propos…
Loop Integrands for Scattering Amplitudes from the Riemann Sphere
Yvonne Geyer, Lionel Mason, Ricardo Monteiro +1
The scattering equations on the Riemann sphere give rise to remarkable formulae for tree-level gauge theory and gravity amplitudes. Adamo, Casali and Skinner conjectured a one-loop…
New Ambitwistor String Theories
Eduardo Casali, Yvonne Geyer, Lionel Mason +2
We describe new ambitwistor string theories that give rise to the recent amplitude formulae for Einstein-Yang-Mills, (Dirac)-Born-Infeld, Galileons and others introduced by Cachazo…
Ambitwistor strings at null infinity and subleading soft limits
Yvonne Geyer, Arthur E. Lipstein, Lionel Mason
The relationships between extended BMS symmetries at null infinity and Weinberg's soft theorems for gravitons and photons together with their subleading generalizations are develop…
Ambitwistor strings in 4-dimensions
Yvonne Geyer, Arthur E. Lipstein, Lionel J. Mason
We develop ambitwistor string theories for 4 dimensions to obtain new formulae for tree-level gauge and gravity amplitudes with arbitrary amounts of supersymmetry. Ambitwistor spac…
A "Twistor String" Inspired Formula For Tree-Level Scattering Amplitudes in N=8 SUGRA
Freddy Cachazo, Yvonne Geyer
We propose a new formulation of the complete tree-level S-matrix of N = 8 supergravity. The new formula for n particles in the k R-charge sector is an integral over the Grassmannia…