More on the Hypercharge Portal into the Dark Sector

Understand

If the hidden sector contains more than one U(1) groups, additional dim-4 couplings (beyond the kinetic mixing) between the massive U(1) fields and the hypercharge generally appear.

• These are of the form similar to the Chern-Simons interactions.
• We study the phenomenology of such couplings including constraints from laboratory experiments and implications for dark matter.
• The hidden vector fields can play the role of dark matter whose characteristic signature would be monochromatic gamma ray emission from the galactic center.