Towards an amplitude analysis of the decay ${\mathrm{\Lambda }}_b^0\to p{K}^{-}\gamma$

The helicity formalism applied to the radiative decay $\Lambda_b^0\to pK^-\gamma$ is presented for the first time in this paper. The aim is to provide the necessary formalism to be able to resolve the resonant $p{K}^{-}$ structures at the photon pole by means of an amplitude analysis. Experimental effects, such as resolution, are also discussed.