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arXiv · 1711.07298

Dispersion theoretic calculation of the $H\rightarrow Z+\gamma$ amplitude

I. Boradjiev·E. Christova·H. Eberl
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Abstract

We have calculated the $W$-loop contribution to the amplitude of the decay $H\rightarrow Z+\gamma$ in two different methods: 1) in the $R_\xi$-gauge using dimensional regularization (DimReg), and 2) in the unitary gauge through the dispersion method. Using the dispersion method we have followed two approaches: i) without subtraction and ii) with subtraction, the subtraction constant being determined adopting the Goldstone boson equivalence theorem (GBET) at the limit $M_W\to 0$. The results of the calculations in $R_\xi$-gauge with DimReg and the dispersion method with the GBET completely coincide, which shows that DimReg is compatible with the dispersion method obeying the GBET.

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I. Boradjiev, E. Christova, H. Eberl. 2017-11-20. Dispersion theoretic calculation of the $H\rightarrow Z+\gamma$ amplitude. https://doi.org/10.1103/physrevd.97.073008

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