Speaker
Sang Hui Im
(Institute for Basic Science, Republic of Korea)
Description
We propose a new mechanism to suppress the axion isocurvature perturbation,
while producing the right amount of axion dark matter, within the framework of
supersymmetric axion models with the axion scale induced by supersymmetry breaking.
The mechanism involves an intermediate phase transition to generate the Higgs
mu-parameter, before which the weak scale is comparable to the axion scale
and the resulting stronger QCD yields an axion mass heavier than the Hubble scale
over a certain period.
Combined with that the Hubble-induced axion scale during the primordial inflation
is well above the intermediate axion scale at present, the stronger QCD in the early
Universe suppresses the axion fluctuation to be small enough even when the inflationary
Hubble scale saturates the current upper bound, while generating an axion
misalignment angle of order unity.
