rishon
/ˈrɪʃɒn/Particle Physics
noun
In a particular model of particle physics: a hypothetical particle postulated as a constituent of quarks and leptons.
- Rishons are conceived as occurring in two kinds, T and V. Different combinations of these form different particles, e.g. TTT a positron and TTV one of the up quarks..
Origin
1970s. From Hebrew ri'šōn first, primary; compare -on. So called as being conceived as more fundamental than the conventionally conceived fundamental particles, quarks and leptons.