Generalized Cuts of Feynman Integrals in Parameter Space.

We propose a construction of generalized cuts of Feynman integrals as an operation on the domain of the Feynman parametric integral. A set of on-shell conditions removes the corresponding boundary components of the integration domain, in favor of including a boundary component from the second Symanzik polynomial. Hence integration domains are full-dimensional spaces with finite volumes, rather than being localized around poles.

Algebraic Structure of Cut Feynman Integrals and the Diagrammatic Coaction.

We study the algebraic and analytic structure of Feynman integrals by proposing an operation that maps an integral into pairs of integrals obtained from a master integrand and a corresponding master contour. This operation is a coaction. It reduces to the known coaction on multiple polylogarithms, but applies more generally, e.

Direct proof of the tree-level scattering amplitude recursion relation in Yang-mills theory.

Recently, by using the known structure of one-loop scattering amplitudes for gluons in Yang-Mills theory, a recursion relation for tree-level scattering amplitudes has been deduced. Here, we give a short and direct proof of this recursion relation based on properties of tree-level amplitudes only.

N=1/2 Wess-Zumino model is renormalizable.

The Wess-Zumino model on N=1/2 nonanticommutative superspace, which contains the dimension-6 term F3, is shown to be renormalizable to all orders in perturbation theory, upon adding F and F2 terms to the original Lagrangian. The renormalizability is possible, even with this higher-dimension operator, because the Lagrangian is not Hermitian. Such deformed field theories arise naturally in string theory with a graviphoton background.