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arXiv · 1512.02860

The Q-cut Representation of One-loop Integrands and Unitarity Cut Method

Rijun Huang·Qingjun Jin·Junjie Rao·Kang Zhou·Bo Feng
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Abstract

Recently, a new construction for complete loop integrands of massless field theories has been proposed, with on-shell tree-level amplitudes delicately incorporated into its algorithm. This new approach reinterprets integrands in a novel form, namely the Q-cut representation. In this paper, by deriving one-loop integrands as examples, we elaborate in details the technique of this new representation, e.g., the summation over all possible Q-cuts as well as helicity states for the non-scalar internal particle in the loop. Moreover, we show that the integrand in the Q-cut representation naturally reduces to the integrand in the traditional unitarity cut method for each given cut channel, providing a cross-check for the new approach.

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Rijun Huang, Qingjun Jin, Junjie Rao, Kang Zhou, Bo Feng. 2016-04-27. The Q-cut Representation of One-loop Integrands and Unitarity Cut Method. https://doi.org/10.1007/jhep03(2016)057

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