Preprint Article Version 2 Preserved in Portico This version is not peer-reviewed

On the Second Dipole Moment of Dirac’s Particle

Version 1 : Received: 18 February 2020 / Approved: 19 February 2020 / Online: 19 February 2020 (10:59:11 CET)
Version 2 : Received: 8 July 2021 / Approved: 8 July 2021 / Online: 8 July 2021 (13:16:31 CEST)
Version 3 : Received: 22 July 2021 / Approved: 26 July 2021 / Online: 26 July 2021 (12:07:54 CEST)

How to cite: Roza, E. On the Second Dipole Moment of Dirac’s Particle. Preprints 2020, 2020020275. Roza, E. On the Second Dipole Moment of Dirac’s Particle. Preprints 2020, 2020020275.


An analysis is presented of the possible existence of a second anomalous dipole moment of Dirac’s particle next to the one associated with the angular momentum. It includes a discussion why, in spite of his own derivation, Dirac has doubted about its relevancy. It is shown why since then it has been overlooked and why it has vanished from leading textbooks. A critical survey is given on the reasons of its reject, including the failure of attempts to measure and the perceived violations of time reversal symmetry and charge-parity symmetry. It is emphasized that the anomalous electric dipole moment of the pointlike electron (AEDM) is fundamentally different from the quantum field type electric dipole moment of an electron (eEDM) as defined in the standard model of particle physics. The analysis has resulted into the identification of a third type Dirac particle, next to the electron type and the Majorana particle. It is shown that, unlike as in the case of the electron type, its second anomalous dipole moment is real valued and is therefore subject to polarization in a vector field. Examples are given that it may have a possible impact in the nuclear domain and in the gravitational domain.


anomalous electric dipole moment; isospin; gravitational Dirac particle


Physical Sciences, Particle and Field Physics

Comments (1)

Comment 1
Received: 8 July 2021
Commenter: Engel Roza
Commenter's Conflict of Interests: Author
Comment: Fifth paragraph modified. Appendix revised. Acknowledgement added. 
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