A note on connections of the Standard Model in a gravitation field
  The Standard Model of the theory of elementary particles is based on the $U(1)\times SU(2)\times SU(3)$ symmetry. In the presence of a gravitation field, i. e. in a non-flat space-time manifold, this symmetry is implemented through three special vector bundles. Connections associated with these vector bundles are studied in this paper. In the Standard Model they are interpreted as gauge fields. 
Ruslan Sharipov