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arXiv · 1906.03298

Physical projectors for multi-leg helicity amplitudes

Tiziano Peraro·Lorenzo Tancredi
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Abstract

We present a method for building physical projector operators for multi-leg helicity amplitudes. For any helicity configuration of the external particles, we define a physical projector which singles out the corresponding helicity amplitude. For processes with more than four external legs, these physical projectors depend on significantly fewer tensor structures and exhibit a remarkable simplicity compared with projector operators defined with traditional approaches. As an example, we present analytic formulas for a complete set of projectors for five-gluon scattering. These have been validated by reproducing known results for five-gluon amplitudes up to one-loop.

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Tiziano Peraro, Lorenzo Tancredi. 2019-06-07. Physical projectors for multi-leg helicity amplitudes. https://doi.org/10.1007/jhep07(2019)114

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