We give a comprehensive review of recent developments on using the pure spinor
formalism to compute massless superstring scattering amplitudes at tree level. The main …

A bstract We study a surprising phenomenon in which Feynman integrals in D= 4− 2ε space-
time dimensions as ε→ 0 can be fully characterized by their behavior in the opposite limit …

A bstract We derive a massive double copy construction within string theory. To this end, we
use massive vectors of the open string spectrum that appear in compactifications to four …

We present a new method, exact in α′, to explicitly compute string tree-level amplitudes
involving one massive state and any number of massless ones. This construction relies on …

We explore the exactly duality invariant higher-derivative extension of double field theory
due to Hohm, Siegel, and Zwiebach specialized to cosmological backgrounds. Despite …

We construct an infinite class of new ultraviolet-complete four-graviton scattering amplitudes
that reduce to Einstein gravity at low energies, vanish at high energies, are meromorphic …

In this Letter, we present the α′-exact background equations of motion of the bosonic chiral
string (also known as Hohm-Siegel-Zwiebach model), with the spin-two ghost fields …

In this letter a new class of twisted strings is presented, with an asymmetry between the
holomorphic and antiholomorphic sectors parametrized by an integer N. Their physical …

A bstract In this paper, we studied the relationship between celestial holography and chiral
strings. Chiral strings differ from the usual string theory by a change of boundary conditions …

We explicitly compute the Neveu-Schwarz sector conventional type-I superstring tree-level
amplitudes at five points after compactifying to 4D, express the QFT building block in the …