Extremely light QCD axions and how to find them

by Pablo Quilez Lasanta (Deutsches Elektronen-Synchrotron (DE))

Thursday 7 Apr 2022, 16:00 → 18:00 Australia/Sydney

We explore whether the axion which solves the strong CP problem can naturally be much lighter than the canonical QCD axion. The Z_N symmetry proposed by Hook, with N mirror and degenerate worlds coexisting in Nature and linked by the axion field, is considered and the associated phenomenology is studied in detail. 

On a second step, we show that dark matter can be accounted for by this extremely light axion. This includes the first proposal of a “fuzzy dark matter” QCD axion. A novel misalignment mechanism occurs – trapped misalignment– , which in some cases can also dynamically source the recently proposed kinetic misalignment mechanism.The resulting universal enhancement of all axion interactions relative to those of the canonical QCD axion has a strong impact on the prospects of ALP experiments such as ALPS II, IAXO and many others. For instance, even Phase I of Casper Electric could discover this axion.

In the last part of my talk, I will briefly comment on a recent idea to look for axions using the LHC as a Light Shining through Wall experiment.

Based on 2102.00012, 2102.01082 and 2204.XXXXX.