Nonlinear chiral forms in Sen formulation of superstring theory*

The Sen formulation for chiral (2p)-form in 4p + 2 dimensions describes a system with two separate sectors, one physical and the other unphysical. Each contains a chiral form and a metric. In this talk, we focus on the self-duality condition for the unphysical sector is linear while the physical sector can be nonlinear. In the case of the general Sen theory, the decoupling at Hamiltonian and Lagrangian levels is presented. Then by applying an appropriate field redefinition of the corresponding first-order Lagrangian, the separation at the Lagrangian level follows. The obtained Lagrangian is separated into two Henneaux-Teitelboim Lagrangians.