  The influence of the geometric phase on a Bell measurement, as proposed by
Bertlmann et al. in [Phys. Rev. A 69, 032112 (2004)], and expressed by the
Clauser-Horne-Shimony-Holt (CHSH) inequality, has been observed for a spin-path
entangled neutron state in an interferometric setup. It is experimentally
demonstrated that the effect of geometric phase can be balanced by a change in
Bell angles. The geometric phase is acquired during a time dependent
interaction with two radio-frequency (rf) fields. Two schemes, polar and
azimuthal adjustment of the Bell angles, are realized and analyzed in detail.
The former scheme, yields a sinusoidal oscillation of the correlation function
S, dependent on the geometric phase, such that it varies in the range between 2
and 2\sqrt{2} and, therefore, always exceeds the boundary value 2 between
quantum mechanic and noncontextual theories. The latter scheme results in a
constant, maximal violation of the Bell-like-CHSH inequality, where S remains
2\sqrt2 for all settings of the geometric phase.
