April 29, 2023
OSU Physics Research Building
America/New_York timezone

Cosmologically Varying Kinetic Mixing

Apr 29, 2023, 2:30 PM
Smith Seminar Room (OSU Physics Research Building)

Smith Seminar Room

OSU Physics Research Building


Xucheng Gan


The portal connecting the invisible and visible sectors is one of the most natural explanations of the dark world. However, the early-time dark matter production via the portal faces extremely stringent late-time constraints. To solve such tension, we construct the scalar-controlled kinetic mixing varying with the ultralight CP-even scalar's cosmological evolution. To realize this and eliminate the constant mixing, we couple the ultralight scalar within the mass range 10−33eV<<m0<<eV with the heavy doubly charged messengers and impose the Z2 symmetry under the dark charge conjugation. Via the varying mixing, the keV−MeV dark photon dark matter is produced through the early-time freeze-in when the scalar is misaligned from the origin and free from the late-time exclusions when the scalar does the damped oscillation and dynamically sets the kinetic mixing. We also find that the scalar-photon coupling emerges from the underlying physics, which changes the cosmological history and provides the experimental targets based on the fine-structure constant variation and the equivalence principle violation.

Presentation materials