A Portalino to the Dark Sector

Understand

"Portal" models that connect the Standard Model to a Dark Sector allow for a wide variety of scenarios beyond the simplest WIMP models.

• Kinetic mixing of gauge fields in particular has allowed a broad range of new ideas.
• However, the models that evade CMB constraints are often non-generic, with new mass scales and operators to split states and suppress indirect detection signals.
• Models with a "portalino", a neutral fermion that marries a linear combination of a standard model neutrino and dark sector fermion and carries a conserved quantum number, can be simpler.