UrQMD simulation of Pb+Pb collisions at 40 GeV/N
and the Lampa-Terrell-Penrose effect

Info:
What ist the Lampa-Terrell-Penrose effect?
 

The MPEG-Movies

both visualize the results of a UrQMD simulation of the collision of two lead nuclei at 40 GeV/N (CERN-SPS) and the following expansion of the fireball, one in the "traditional way", the other taking into account the Lampa-Terrell-Penrose effect.

The movie pb040pb_labframe.mpg shows the time evolution of a collision in the plane of the beam axis (horizontal axis) and the impact parameter axis (vertical axis). This is the usual visualization depicting the positions of the particles involved in space and time. The impinging nuclei are compressed to ellipsoids by Lorentz contraction.

(click on the picture to get the movie)



The movie pb040pb_lampaterell.mpg shows the time evolution as above, but this time as seen "in the light of photons" scattering off the moving particles. The observer is located on the y axis (the horizontal axes, z, is gain the beam axis, the vertical axis, x, the impact parameter axis) at a distance of 20 fm from the center of the collision. Due to the final speed of light and the relativistic velocities of the particles involved, one does in fact not "see" the Lorentz contraction. Instead, the nuclei look like spheres which are in fact rotated. This is the Lampa-Terrell-Penrose effect. However, the visualization only takes into account the timing of the emission of light and the arrival at the observer. Changing "colors" due to the Doppler effect are not considered.

(click on the picture to get the movie)



The colours in the movies respresent:



27.02.2001, Stefan Scherer, e-mail: scherer@th.physik.uni-frankfurt.de