Experimental investigation of left-right asymmetry in photon-atom interaction

TL;DR

This study investigates the left-right asymmetry in photon-atom interactions using angle- and energy-resolved photoelectron spectroscopy, revealing significant asymmetries in noble gas atoms and molecules, and analyzing their energy dependence.

Contribution

It provides the first detailed experimental measurements of LRA parameters for various noble gases and molecules, clarifying the asymmetry's dependence on photon and electron energies.

Findings

Significant non-zero LRA parameters observed for s- and p-shells.

LRA varies with photon and electron energy levels.

Experimental and instrumental sources of asymmetry are ruled out.

Abstract

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.