AtlasHepMC: HepMC3 polarization fix.
Add a is_defined flag to Polarization, rather than just testing if the angles are both zero. Fixes problems seen with polarization information disappearing during conversions.
See ATLASRECTS-6859.
Add a is_defined flag to Polarization, rather than just testing if the angles are both zero. Fixes problems seen with polarization information disappearing during conversions.
See ATLASRECTS-6859.