Axion Seach Experiment, Past and Future
Axion is a hypothetical particle, originally proposed to solve the Strong CP problemin the QCD theory. Axion is believed to be generated in the early universe, and it is
known to be one of the candidates of cosmic dark matter. Many search experiments
were performed, but the existence of axion has not been established yet.
From the recent observation on the cosmic microwave and the theoretical calculation,
it is suggested that the axion has a mass of O(100) eV. We are aiming to search for
axion in this mass region (New-CARRACK project).
In the New-CARRACK project, we are planning to search for axion by using a single
photon detection method. Single photon detection is free from the standard quantum
limit and allows us to search for axion with a wide range of mass without degrading
its detection sensitivity. Besides, we proposed a new innovative method to search for
axion in a wide mass range by using photo-ionization processes.
In this colloquium, the physics motivation to search for axion will be introduced, and
the current status of the experimental search results will be reviewed. Then the
overview of New-CARRACK project and the preparation status will be shown.