Kinetic mixing of U(1)s for local string models

Understand

We study kinetic mixing between massless U(1)s in toroidal orbifolds with D3-branes at orbifold singularities.

• We focus in particular on C^3/Z_4 singularities but also study C^3/Z_6 and C^3/Z'_6 singularities.
• We find kinetic mixing can be present and describe the conditions for it to occur.
• Kinetic mixing comes from winding modes in the N=2 sector of the orbifold.