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arXiv · 1201.1523

Tree amplitudes and color decomposition in broken SU(2)

Liang Dai·Kirill Melnikov·Fabrizio Caola
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Abstract

We propose a color decomposition for general tree amplitudes in a SU(2) gauge theory which is spontaneously broken via the Higgs mechanism. Working in the unitary gauge, we construct color-ordered amplitudes by explicitly presenting a set of color-ordered Feynman rules. Those primitive amplitudes are gauge-invariant, and they preserve perturbative unitarity in the high-energy limit. Serving as building blocks of color-dressed tree amplitudes, they allow for efficient evaluation of tree-level scattering amplitudes involving gauge bosons and the Higgs boson via the Berends-Giele recursion relations for color-ordered currents. We demonstrate the efficiency of this computational scheme by calculating on-shell amplitudes for scattering of five, six and nine W-bosons in the limit of vanishing Weinberg angle.

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Liang Dai, Kirill Melnikov, Fabrizio Caola. 2012-01-07. Tree amplitudes and color decomposition in broken SU(2). https://doi.org/10.1007/jhep04(2012)095

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