Prootonids

Prootonids are a proposed class of hypothetical particles arising in certain beyond-Standard-Model theories that extend the concept of substructure in matter. The term combines "proto" with a suffix indicating a particle, reflecting their role as elementary constituents in new theoretical frameworks or as bound states within a hidden sector. They are designed to address open questions in particle physics, such as the nature of dark matter or the origin of baryon asymmetry, without being part of the ordinary hadron spectrum.

In preon- or hidden-sector models, prootonids can be either fermions or bosons and may carry neutral or small electric charge depending on the realization. They generally interact weakly with Standard Model particles, typically via a portal to a hidden gauge group or through higher-dimensional operators. Their masses are model-dependent, spanning broad ranges from sub-eV to multi-TeV scales. Some scenarios describe prootonids as stable on cosmological timescales, while others predict long but finite lifetimes.

Phenomenology varies with the underlying theory. At colliders, prootonids might be produced in pairs and manifest as missing energy or displaced vertices if they decay, or as resonances if they form bound states. Direct detection experiments could probe their scattering with nuclei only if a portal to the Standard Model exists. Astrophysical and cosmological observations constrain their abundance and decay products, limiting viable parameter space.

To date, there is no experimental confirmation of prootonids. They remain a speculative component of certain beyond-Standard-Model programs, used to illustrate how hidden-sector dynamics could influence visible matter. Ongoing searches in high-energy physics and astroparticle experiments continue to test related predictions, refining theoretical models and guiding future experimental strategies.