Extended Data Fig. 1: Full set of projections of a measured Poincaré surface of section.
From: Observation of fixed lines induced by a nonlinear resonance in the CERN Super Proton Synchrotron
In these pictures (a-f) we show all 6 two-dimensional phase space projections. The data corresponds to the same shot as shown in Fig. 2. The blue markers are the normalized beam coordinates obtained experimentally from 3,000 passages through the selected longitudinal observation point. The spread of the markers yields a direct information on the random error created by the four BPMs, with a standard deviation σBPM,x ≈ 0.66 mm, and σBPM,y ≈ 0.5 mm. The red line is the best fit of Eq. (1) to the experimental data, which confirms that the topology is consistent with a fixed line.
