Existence of previously unknown physical phenomenon – spin dichroism and spin rotation of high-energy relativistic deuterons in unpolarized medium was theoretically proved and observed experimentally. 
Spin dichroism was observed experimentally in 2003 by collaboration between INP and COSY (Germany). 

One of the most fundamental principles of modern physical theories - causality principle - can be verified using this effect.

In April-May 2006 scientists of INP BSU jointly with scientists from the Institute of nuclear physics (Juelich, Germany) and Institute of nuclear physics of University of Cologne (Germany) the second experiment was carried out to observe spin dichroism of deuterons in unpolarized carbon target for energy range up to 20 MeV.
Results:
1) thanks to the improvements of experimental method, asymmetry between peripheral and central detectors of the polarimeter was observed more sharply, that suggests the emergence of tensor polarisation (spin dichroism) in unpolarized deuteron beam;
2) new experimental data have good correlation with experimental data from 2003;
3) the magnitude of spin dichroism is as high as -0.15 for carbon target 132 mg/cm²; thick
4) spin dichroism depends both on the target thickness and on the energy of deutrons in the target.