Cosmic Ray Extremely Distributed Observatory 2021

Cosmic Ray Ensembles (CRE) are large, yet not observed particle cascades initiated above the Earth atmosphere. Such cascades could be formed both within classical models (e.g. products of photon-photon interactions) and exotic scenarios (e.g. as a result of decay of Super Heavy Dark Matter particles and subsequent interactions). Some of CRE might have a significant spatial extent which could serve as a unique signature detectable with the existing cosmic ray infrastructure taken as a network of detectors. CRE identification could then be possible, for an example, with a detection of a number of well separated air showers with parallel axes. An obvious, although yet not probed, CRE „detection horizon” can be located somewhere between an air shower induced by a CRE composed of tightly collimated particles (preshower effect), and undetectable CRE composed of particles spread so widely that only one of them has a chance to reach Earth. Probing the CRE horizon with a global approach to the cosmic ray data, as proposed by the Cosmic Ray Extremely Distributed Observatory (CREDO), defines an extensive scientific program oriented mostly on the search for physics manifestations at the largest energies known, with potential impact on ultra-high energy astroparticle physics, multi-messenger astrophysics, cosmology, and even foundations of science. In this talk the current scientific status and perspectives of CREDO will be summarized, with an open invitation for the colleagues interested in a global and interdisciplinary approach to cosmic ray research, and in particular in the observations and studies concerning multi-primary cosmic ray events.