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

The resonant structure of the radiative decay ${\mathrm{\Lambda }}_b^0\to p{K}^{-}\gamma$ in the region of proton-kaon invariant-mass up to 2.5 GeV$\mathrm{/}{c}^2$ is studied using proton-proton collision data recorded at centre-of-mass energies of 7, 8, and 13 TeV collected with the LHCb detector, corresponding to a total integrated luminosity of 9 fb${}^{-1}$. Results are given in terms of fit and interference fractions between the different components contributing to this final state. Only $\mathrm{\Lambda }$ resonances decaying to $p{K}^{-}$ are found to be relevant, where the largest contributions stem from the $\mathrm{\Lambda }(1520)$, $\mathrm{\Lambda }(1600)$, $\mathrm{\Lambda }(1800)$, and $\mathrm{\Lambda }(1890)$ states.