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 \( \mathcal{Q} \)-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 \( \mathcal{Q} \)-cuts as well as helicity states for the non-scalar internal particle in the loop. Moreover, we show that the integrand in the \( \mathcal{Q} \)-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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ArXiv ePrint: 1512.02860
The unusual ordering of authors is just to let authors get proper recognition of contributions under outdated practice in China.
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Huang, R., Jin, Q., Rao, J. et al. The \( \mathcal{Q} \)-cut representation of one-loop integrands and unitarity cut method. J. High Energ. Phys. 2016, 57 (2016). https://doi.org/10.1007/JHEP03(2016)057
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DOI: https://doi.org/10.1007/JHEP03(2016)057