992 research outputs found
Fermionic one-loop amplitudes of the RNS superstring
We investigate massless n-point one-loop amplitudes of the open RNS
superstring with two external fermions and determine their worldsheet
integrands. The contributing correlation functions involving spin-1/2 and
spin-3/2 operators from the fermion vertices are evaluated to any multiplicity.
Moreover, we introduce techniques to sum these correlators over the spin
structures of the worldsheet fermions such as to manifest all cancellations due
to spacetime supersymmetry. These spin sums require generalizations of the
Riemann identities among Jacobi theta functions, and the results can be
expressed in terms of doubly-periodic functions known from the mathematics
literature on elliptic multiple zeta values. On the boundary of moduli space,
our spin-summed correlators specialize to compact representations of fermionic
one-loop integrands for ambitwistor strings.Comment: 42+24 pages, v2: published version, minor corrections in (4.5), (4.8)
and (4.15
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