  Experimental data on transverse single-spin asymmetry, hyperon polarization
and vector meson alignment in h+h, h+A and A+A-collisions have been analyzed. A
new mechanism for the origin of single spin effects is proposed, which takes
into account the interaction of massive constituent quarks via their
chromomagnetic moment with an effective inhomogeneous chromomagnetic field of
strings, produced after the initial color exchange. Quark spin precession in
the color field is taken into account, which can be the reason for an
oscillation of the single spin observables as a function of Feynman $x_{F}$ and
its energy dependence. The model predictions are compared with the experimental
data, in particular with the heavy ion collision data. The data are consistent
with a large negative anomalous chromomagnetic moment of the constituent quarks
which is predicted in the instanton model.
