  Single ionization of noble gas atoms by linearly polarized synchrotron
radiation has been studied by employing angle- and energy-resolved
photoelectron spectroscopy. The measurements were carried out in the plane
defined by the momentum and polarization vectors of the photon. Parameters
describing the left-right asymmetry (LRA) (relative to the photon propagation
direction) of the photoelectron angular distribution were determined
experimentally for the $s$-shells of He, Ne, Ar, Kr and Xe atoms and H$_2$
molecules and for the $p$-shells of Ne, Ar, Kr and Xe atoms. The values of the
left-right asymmetry differ significantly from zero for both subshells. The
photon and photoelectron energy dependence of the LRA parameters are presented
also. Possible experimental and instrumental sources that could generate
asymmetry are discussed and excluded as well.
