Torsion axial vector and Yvon-Takabayashi angle: zitterbewegung, chirality and all that Luca Fabbri and Roldão da Rocha Eur. Phys. J. C, 78 3 (2018) 207 Published online: 13 March 2018 DOI: 10.1140/epjc/s10052-018-5706-3