2,645 research outputs found
Scattering Equations, Twistor-string Formulas and Double-soft Limits in Four Dimensions
We study scattering equations and formulas for tree amplitudes of various
theories in four dimensions, in terms of spinor helicity variables and on-shell
superspace for supersymmetric theories. As originally obtained in Witten's
twistor string theory and other twistor-string models, the equations can take
either polynomial or rational forms, and we clarify the simple relation between
them. We present new, four-dimensional formulas for all tree amplitudes in the
non-linear sigma model, a special Galileon theory and the maximally
supersymmetric completion of the Dirac-Born-Infeld theory. Furthermore, we
apply the formulas to study various double-soft theorems in these theories,
including the emissions of a pair of soft photons, fermions and scalars for
super-amplitudes in super-DBI theory.Comment: 22 pages, 2 tables; v2: ref added, minor typos fixe
The Computation of the Matching Polynomials of Fullerene Graphs
A new formula for the evaluation of the matching polynomials of fullerene graphs is presented
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