Continuous spin particle

Continuous spin particle (or CSP in short), sometimes called an infinite spin particle, is known as a massless particle never observed before in nature. This particle is one of Poincaré group's massless representations which along with ordinary massless particles was classified by Eugene Wigner in 1939. Historically, a compatible theory that could describe this elementary particle was unknown, however, 75 years after Wigner's classification, the first local action principle for bosonic continuous spin particles was introduced in 2014, and the first local action principle for fermionic continuous spin particles was suggested in 2015. It has been illustrated that this particle can interact with matter in flat space-time. It is expected to observe this particle (if any) in high energies at CERN or a next-generation particle accelerator, however, so far no energy scale has been proposed at which this particle can be observed. In this regard, it would be also interesting to do research and find a trace of CSP in the early universe. Supersymmetric continuous spin gauge theory has been studied in three and four spacetime dimensions. 
In condensed matter systems, CSPs can be understood as massless generalizations of the anyon, so it may be easier to observe this particle in these systems than observation in high-energy accelerators, however, no effort has been made so far. 