Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Massive Relativistic Particle Model with Spin and Electric Charge from
  Two-Twistor Dynamics   The sixteen real coordinates of two-twistor space are transformed by a
nonlinear mapping into an enlarged space-time framework. The standard
relativistic phase space of coordinates $(X_\mu, P_\mu)$ is supplemented by a
six-parameter spin phase manifold (two pairs $(\eta_\alpha,\sigma_\alpha)$ and
$(\bar{\eta}_{\dot\alpha}, \bar{\sigma}_{\dot{\alpha}})$ of canonically
conjugated Weyl spinors constrained by two second class constraints) and the
electric charge phase space ($e,\phi$). The free two-twistor classical
mechanics is rewritten in this enlarged relativistic phase space as a model for
a relativistic particle. Definite values for the mass, spin and the electric
charge of the particle are introduced by means of three first class
constraints.

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The categories of this paper are: eess
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The categories of this paper are: plasm-ph
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The categories of this paper are: cs
5
The categories of this paper are: gr-qc
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The categories of this paper are: solv-int
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The categories of this paper are: astro-ph
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The categories of this paper are: adap-org
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The categories of this paper are: hep-ex
4
The categories of this paper are: cond-mat
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The categories of this paper are: cmp-lg
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The categories of this paper are: chao-dyn
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The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
2
The categories of this paper are: math
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The categories of this paper are: q-bio
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The categories of this paper are: mtrl-th