Publications about the Spin structure of Elementary Particles
spin structure of elementary particles has been considered a pure
quantum mechanical and relativistic property.
It is attributed to Pauli the statement that the spin cannot be explained classically. But what Pauli said was that “the two-valuedness of spin is a physical property which cannot be explained classically”, i.e., the spin of elementary particles is quantized.
Please, see here what very excellent quantum mechanics books say about the spin of the electron.
The spin is an angular momentum and as such it is a mechanical property related to the rotation invariance of the fundamental physical laws and in this sense it has nothing to do with relativity. Any angular momentum is a property defined with respect some fixed point and this point has to be clearly identified. Dirac spin operator is not the angular momentum of the particle with respect to the center of mass. It is clear that the sum of the three spin observables associated to the quarks cannot give the spin of the proton. We have to add the three angular momentum observables of the quarks with respect to their centre of masses. See the discussion concerning the generalized use of two different spin observables for describing the angular momentum of particles.
It is usually stated that the electron does not rotate. We see that all matter which surrounds us moves and rotates. According to this the only exception are the elementary particles. It is nonsense.
The electron has a directional property, the spin, and the associated magnetic moment, which define a direction in space. These properties change their orientation, and thus we associate to this change of orientation a rotation of the electron.
What does not change is the absolute value of the spin. It is physically impossible to modify the value of the spin of the electron. This has to be raised to a fundamental physical law.
Elementary particles, if not annihilated, can never be modified its internal structure and therefore they do not have excited states.
formalism of elementary spinning particles (pdf)
Lecture Course to be given at the Center for Theoretical Physics
Jamia Millia Islamia, New Delhi, November 2007
theory of spinning particles: The interaction Lagrangian for two
spin 1/2 elementary Dirac particles(pdf)
Plenary lectures of the Advanced Studies Institute, Symmetries and Spin, Prague 19-26 July 2006.
The interaction Lagrangian of two spin 1/2 elementary Dirac particles(pdf)
Contribution to the Colloquium on Group Theoretical Methods on Physics CUNY NewYork, 26-30 June 2006
formalism of elementary spinning particles
Lecture Course given at JINR, Dubna, 19-23 September 2005
elementary particles, spin, zitterbewegung and all that
structure of classical and quantum mechanical spin
(Czec.J.Phys. 52, C453 (2002))(pdf)
the electron spin and magnetic moment parallel or antiparallel
Lagrangians and spinning particles
Contribution to a special issue in the 200th Ostrogradskii anniversary by the Ukrainian Mathematical Society
(Ukrainian Math. J. 53, 1326 (2001))(pdf)
pure kinematical explanation of the gyromagnetic ratio g=2 of
leptons and charged bosons
(Phys. Lett. A, 257, 21 (1999) )
(in collaboration with J.M. Aguirregabiria and A. Hernandez) (pdf)
there a classical spin contribution to the tunnel effect?
(Phys. Lett. A, 248, 279 (1998)) (pdf)
of generalized spinning particles. New derivation of Dirac’s
(J. Math. Phys. 35,3380 (1994)) (pdf)
relativistic spinning particles
(J. Math. Phys. 30,318 (1989)) (pdf)
particle systems: I Galilei free particle
(J. Phys. A: Math. and General, 18, 1971 (1985) (pdf)