353 research outputs found
On-shell supersymmetry for massive multiplets
The consequences of on-shell supersymmetry are studied for scattering
amplitudes with massive particles in four dimensions. Using the massive version
of the spinor helicity formalism the supersymmetry transformations relating
products of on-shell states are derived directly from the on-shell
supersymmetry algebra for any massive representation. Solutions to the
resulting Ward identities can be constructed as functions on the on-shell
superspaces that are obtained from the coherent state method. In simple cases
it is shown that these superspaces allow one to construct explicitly
supersymmetric scattering amplitudes. Supersymmetric on-shell recursion
relations for tree-level superamplitudes with massive particles are introduced.
As examples, simple supersymmetric amplitudes are constructed in SQCD, the
Abelian Higgs model, the Coulomb branch of N=4 super Yang-Mills, QCD with an
effective Higgs-gluon coupling and for massive vector boson currents.Comment: 49+9 pages, 4 figures, v2: references updated, typos corrected,
examples added, v3: final PRD versio
Disk level S-matrix elements at eikonal Regge limit
We examine the calculation of the color-ordered disk level S-matrix element
of massless scalar vertex operators for the special case that some of the
Mandelstam variables for which there are no open string channel in the
amplitude, are set to zero. By explicit calculation we show that the string
form factors in the 2n-point functions reduce to one at the eikonal Regge
limit.Comment: 17 pages, Latex file, no figur
Three particle superstring amplitudes with massive legs
On-shell superspaces and associated spinor helicity techniques give an
efficient formulation of the Ward identities of on-shell supersymmetry for
scattering amplitudes and supply tools to construct their solutions. Based on
these techniques in this paper the general solutions of the Ward identities are
presented for three particle scattering amplitudes with one, two or three
massive legs for simple supersymmetry in ten and eight dimensions. It is shown
in examples how these solutions may be used to obtain concrete amplitudes for
the closed (IIB) and open superstring in a flat background. Explicit results
include all three point amplitudes with one massive leg whose functional form
is shown to be dictated completely by super-Poincare symmetry. The resulting
surprisingly simple series only involves massive superfields labelled by
completely symmetric little group representations. The extension to more
general explicit three and higher point amplitudes in string theory is
initiated. In appendices the field content of the fundamental massive
superfields of the open and closed superstring are listed in terms of the
Dynkin labels of a variety of groups which may be of independent interest.Comment: 45 pages. v2: typos corrected, references adde
Factorization of Seiberg-Witten Curves and Compactification to Three Dimensions
We continue our study of nonperturbative superpotentials of four-dimensional
N=2 supersymmetric gauge theories with gauge group U(N) on R^3 x S^1, broken to
N=1 due to a classical superpotential. In a previous paper, hep-th/0304061, we
discussed how the low-energy quantum superpotential can be obtained by
substituting the Lax matrix of the underlying integrable system directly into
the classical superpotential. In this paper we prove algebraically that this
recipe yields the correct factorization of the Seiberg-Witten curves, which is
an important check of the conjecture. We will also give an independent proof
using the algebraic-geometrical interpretation of the underlying integrable
system.Comment: laTeX, 14 pages, uses AMSmat
Symmetries of the Self-Dual Sector of N=4 Super Yang-Mills on the Light Cone
A recent paper proposes a way of constructing infinite dimensional symmetries
of the non-supersymmetric self-dual Yang-Mills action using isometries of the
space-time. We review the Lagrangian formulation of N = 4 super Yang-Mills MHV
rules and extend the approach taken for the non-supersymmetric case to
construct infinite dimensional symmetries of self-dual N = 4 super Yang-Mills.Comment: 22 pages, 8 figures. V[2] Added references and minor typographical
correction
The Whitham Deformation of the Dijkgraaf-Vafa Theory
We discuss the Whitham deformation of the effective superpotential in the
Dijkgraaf-Vafa (DV) theory. It amounts to discussing the Whitham deformation of
an underlying (hyper)elliptic curve. Taking the elliptic case for simplicity we
derive the Whitham equation for the period, which governs flowings of branch
points on the Riemann surface. By studying the hodograph solution to the
Whitham equation it is shown that the effective superpotential in the DV theory
is realized by many different meromorphic differentials. Depending on which
meromorphic differential to take, the effective superpotential undergoes
different deformations. This aspect of the DV theory is discussed in detail by
taking the N=1^* theory. We give a physical interpretation of the deformation
parameters.Comment: 35pages, 1 figure; v2: one section added to give a physical
interpretation of the deformation parameters, one reference added, minor
corrections; v4: minor correction
Supersymmetric Gauge Theories in Twistor Space
We construct a twistor space action for N=4 super Yang-Mills theory and show
that it is equivalent to its four dimensional spacetime counterpart at the
level of perturbation theory. We compare our partition function to the original
twistor-string proposal, showing that although our theory is closely related to
string theory, it is free from conformal supergravity. We also provide twistor
actions for gauge theories with N<4 supersymmetry, and show how matter
multiplets may be coupled to the gauge sector.Comment: 23 pages, no figure
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