54 research outputs found
The BLG Theory in Light-Cone Superspace
The light-cone superspace version of the d=3, N=8 superconformal theory of
Bagger, Lambert and Gustavsson (BLG) is obtained as a solution to constraints
imposed by OSp(2,2|8) superalgebra. The Hamiltonian of the theory is shown to
be a quadratic form of the dynamical supersymmetry transformation.Comment: 45 pages, v2: reference added, minor typos corrected, published
versio
Towards a tensionless string field theory for the N=(2,0) CFT in d=6
We describe progress in using the field theory of tensionless strings to
arrive at a Lagrangian for the six-dimensional conformal
theory. We construct the free part of the theory and propose an ansatz for the
cubic vertex in light-cone superspace. By requiring closure of the
supersymmetry algebra, we fix the cubic vertex up to two parameters.Comment: 46 pages, 2 figures. V2: references added; minor changes and
improvement
From lightcone actions to maximally supersymmetric amplitudes
In this article actions for N=4 SYM and N=8 supergravity are formulated in
terms of a chiral superfield, which contains only the physical degrees of
freedom of either theory. In these new actions, which originate from the
lightcone superspace, the supergravity cubic vertex is the square of the gauge
theory one (omitting the color structures). Amplitude calculations using the
corresponding Feynman supergraph rules are tedious, but can be simplified by
choosing a preferred superframe. Recursive calculations of all MHV amplitudes
in N=4 SYM and the four-point N=8 supergravity amplitude are shown to agree
with the known results and connections to the BCFW recursion relations are
pointed out. Finally, the new path integrals are discussed in the context of
the double-copy property relating N=4 SYM theory to N=8 supergravity.Comment: 29 pages, 2 figures, v2: title modified, published versio
Pure spinor superfields -- an overview
Maximally supersymmetric theories do not allow off-shell superspace
formulations with traditional superfields containing a finite set of auxiliary
fields. It has become clear that off-shell supersymmetric action formulations
of such models can be achieved by the introduction of pure spinors. In this
talk, an overview of this formalism is given, with emphasis on D=10
super-Yang-Mills theory and D=11 supergravity. This a somewhat expanded version
of a talk presented at the workshop "Breaking of supersymmetry and ultraviolet
divergences in extended supergravity" (BUDS), Laboratori Nazionali di Frascati,
March 25-28, 2013.Comment: 34 pp., 2 figs., contributions to the proceedings of the workshop
"Breaking of supersymmetry and ultraviolet divergences in extended
supergravity" (BUDS), Laboratori Nazionali di Frascati, March 25-28, 201
Conformal higher spin scattering amplitudes from twistor space
We use the formulation of conformal higher spin (CHS) theories in twistor
space to study their tree-level scattering amplitudes, finding expressions for
all three-point anti-MHV amplitudes and all MHV amplitudes involving positive
helicity conformal gravity particles and two negative helicity higher spins.
This provides the on-shell analogue for the covariant coupling of CHS fields to
a conformal gravity background. We discuss the restriction of the theory to a
ghost-free unitary subsector, analogous to restricting conformal gravity to
general relativity with a cosmological constant. We study the flat-space limit
and show that the restricted amplitudes vanish, supporting the conjecture that
in the unitary sector the S-matrix of CHS theories is trivial. However, by
appropriately rescaling the amplitudes we find non-vanishing results which we
compare with chiral flat-space higher spin theories.Comment: 31 pages, no figures. v2: comments added, published versio
Exceptional versus superPoincaré algebra as the defining symmetry of maximal supergravity
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