Speaker
Description
Active-sterile mixing is the simplest mechanism to produce sterile neutrinos in the
early Universe. However, the generic production mechanism, known as the Dodelson-Widrow mechanism, is in tension with the astrophysical bounds coming from structure
formation and X-ray observations. Thus, it is necessary to introduce new interactions
to modify the DW production, as this mechanism is unavoidable if we assume non-zero mixing between neutrino flavors. In contrast to previous studies, we employ
an effective field theory treatment to introduce non-standard neutrino interactions to
the early Universe. We work out the details of scalar, pseudoscalar and axial vector
self-interactions with heavy mediators. We find that the production of keV sterile
neutrinos can be enhanced or suppressed depending on the non-standard interaction
strength, and this helps the mechanism evade astrophysical constraints or move closer
to future experimental sensitivities
