  A quark interaction with topologically nontrivial gluonic fields, instantons
and sphalerons, violates \P~ and \CP~ symmetry. In the strong magnetic field of
a noncentral nuclear collision such interactions lead to the charge separation
along the magnetic field, the so-called chiral magnetic effect (CME). Recent
results from the STAR collaboration on charge dependent correlations are
consistent with theoretical expectations for CME but may have contributions
from other effects, which prevents definitive interpretation of the data. Here
I propose to use central body-body $U+U$ collisions to disentangle correlations
due to CME from possible background correlations due to elliptic flow. Further
more quantitative studies can be performed with collision of isobaric beams.
