Preon trinity—A schematic model of leptons, quarks and heavy vector bosons

Abstract

PACS. 12.15.Ff -Quark and lepton masses and mixing. PACS. 12.60.Rc -Composite models. PACS. 14.60.St -Non-standard-model neutrinos, right-handed neutrinos, etc..Abstract. -Quarks, leptons and heavy vector bosons are suggested to be composed of stable spin-1/2 preons, existing in three flavours, combined according to simple rules. Straightforward consequences of an SU (3) preon-flavour symmetry are the conservation of three lepton numbers, oscillations and decays between some neutrinos, and the mixing of the d and s quarks, as well as of the vector fields W 0 and B 0 . We find a relation between the Cabibbo and Weinberg mixing angles, and predict new (heavy) leptons, quarks and vector bosons, some of which might be observable at the Fermilab Tevatron and the future CERN LHC. A heavy neutrino might even be visible in existing data from the CERN LEP facility.Introduction. -The phenomenological success of the standard model of quarks and leptons, and their observed patterns, indicate that there exist a more fundamental basis. Here we present a simple preon model where leptons, quarks and heavy vector bosons are composite, and where many of the ad hoc ingredients of the standard model are clear-cut consequences of this inner structure. We limit the present discussion to straightforward, qualitative consequences of the model, and leave a more quantitative analysis, requiring extra assumptions, to future publications.Although there is currently no direct experimental evidence for (or against) preons, there are quite a few phenomenological, and logical, circumstances that point at compositeness, some of which have been known for long [1]:• There are "too many" leptons and quarks, but still a pattern among them. Historically, such patterns have led to ideas about compositeness, with the quark model as a modern example, and the periodic system as an older one.• The least elegant (mathematical) features of the standard model are due to the weak gauge bosons being massive (and unstable and of different charges). They might be preon-antipreon states, in analogy to the nuclear force being "leaked" by quark-antiquark states. If so, there is no fundamental weak force, nor a Higgs mechanism. The photon-Z 0 mixing is equivalent to the photon-ρ 0 mixing in the vector-dominance model.

Preon stars: a new class of cosmic compact objects

“…We have briefly noted their potential importance for dark matter and ultra-high energy cosmic rays, connections that also could be used to observe them. This might provide alternative means for constraining and testing different preon models, in addition to direct tests [8] performed at particle accelerators.…”

“…The possibilities are, e.g., supersymmetric particles, new dimensions and compositeness. In this letter we consider "preon models" [7,8], i.e., models in which quarks and leptons, and sometimes some of the gauge bosons, are composite particles built out of more elementary preons. If fermionic preons exist, it seems reasonable that a new type of astrophysical compact object, a preon star, could exist.…”

Compact stars in the standard model - and beyond

“…Due to the need for observational clues in the cold dark matter sector, this could prove compositeness plausible, without much dedicated effort. This approach might complement direct tests of preon models [13] performed at particle accelerators. …”

“…Later, it was shown that with another choice for the gauge group and the flavour structure of preons, e.g., three different preon flavours, the consistency conditions are satisfied [12]. For a more detailed discussion of preon models, see [9,10,13] and references therein.…”

A cyclic universe with colour fields

“…As we have already mentioned, all of the previous composite models explain the observed variety of elementary particles by different combinations of a certain number of preon types, reduced with respect to the number of the fundamental types in the standard model [121][122][123][124][125]. However, it is plain to see that even this reduced number cannot solve the problem.…”