An exemplary burner of a gas turbine includes a tubular body with an inlet for an entrance of an air flow, downstream of inlet vortex generators, and a lance projecting into the tubular body and having a terminal portion extending along a longitudinal axis of the burner which is provided with nozzle groups for injecting fuel into the tubular body. The nozzle groups can lay in an injection plane perpendicular to the axis of the terminal portion of the lance. Downstream of the lance, the burner has an outlet. A ratio x/L between an axial distance x between the side trailing edge of the vortex generator and the injection plane, and the length L of the tubular body can be less than approximately 0.1052.