  We give a general parameterization of the Lambda_b --> Lambda(1520) gamma
decay amplitude, applicable to any strange isosinglet spin-3/2 baryon, and
calculate the branching fraction and helicity amplitudes. Large-energy form
factor relations are worked out, and it is shown that the helicity-3/2
amplitudes vanish at lowest order in soft-collinear effective theory (SCET).
The suppression can be tested experimentally at the LHC and elsewhere, thus
providing a benchmark for SCET. We apply the results to assess the experimental
reach for a possible wrong-helicity b --> s gamma dipole coupling in Lambda_b
--> Lambda(1520) gamma --> p K gamma decays. Furthermore we revisit
Lambda_b-polarization at hadron colliders and update the prediction from
heavy-quark effective theory. Opportunities associated with b --> d gamma
afforded by high-statistics Lambda_b samples are briefly discussed in the
general context of CP and flavour violation.
