There are lots of issues with preon models that model at least some of the Standard Model fundamental particles as composite (experimental limits on compositeness are strict and naively rule them out for simpler models). But this is a more interesting one than most.
We build a framework for Regge trajectories from the Nambu-Goto action. We compute the 6-preon Regge trajectory in a preon model, include the worldsheet conformal anomaly, and build the parameter-free Veneziano amplitude. The amplitude has s-channel poles matching the spectrum to 0.5%, and at fixed-angle scattering decays exponentially with a negative Gross-Mende coefficient, realized numerically to 0.03%.
This is a soft, genuinely non-perturbative ultraviolet completion of the preon model - and thereby of the Standard Model, which emerges as its low-energy limit.
Risto Raitio, "Soft UV Completion of a Preon Model" arXiv:2606.06541 (June 4, 2026).
The model used in this case is spelled out in the introduction:
Quarks and leptons arise as three-preon composites bound at the metacolor scale Λ(cr); the three fermion generations emerge not as a postulated multiplicity but as dynamical excitations of these composites; and the chiral, anomaly-free matter content of one Standard Model family is reproduced from a small set of preon charges. In this picture the Standard Model is the low-energy limit of a confining metacolor gauge theory, much as hadronic physics is the low-energy limit of QCD.
6 comments:
Risto Raitio has been developing this for a long time - see the acknowledgements - it started in the 1970s with the idea that the charm quark is an excited up quark!
I am mildly interested in comparing it with Alejandro's sBootstrap. Maybe a significant difference is that Raitio has susy at the level of preons but not at the level of the composites they form, whereas the sBootstrap is in part about a quasi-susy within the standard model once you include mesons and diquarks alongside the elementary particles.
Maybe a significant difference is that Raitio has susy at the level of preons but not at the level of the composites they form
so no susy particles ?
Risto Raitio, "Soft UV Completion of a Preon Model" arXiv:2606.06541 (June 4, 2026).
do bosons have susy partners like gluinos and hasn't LHC rules out to 2tev?
There is no positive evidence of SUSY. It was designed to address issues at the electroweak scale (i.e. up to hundreds of GeVs) and it wasn't there. SUSY partners make bad dark matter candidates. There is really nothing to motivate SUSY but mathematical convenience (as distinct from mathematical necessity).
@neo is right about the roughly 2 TeV experimental cutoff for many kinds of super partners, but what that cutoff fails to capture is that the cutoff is almost entirely due to the limits of the instrumentation and that there are no experimental "hints" of something beyond it and no good theoretical motivations for it.
"This paper presents a search for beyond the standard model physics using single-lepton events with a high multiplicity of jets, including those identified as bottom quark jets, without a requirement on missing transverse momentum. The analysis is based on proton-proton collision data collected with the CMS detector at the CERN LHC at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb^−1. This search is sensitive to R-parity violating supersymmetry models, where supersymmetric particles can decay into standard-model particles through interactions that violate baryon number conservation. In particular, the signal model considered is gluino pair production, where each gluino decays into top, bottom, and strange quarks. The sum of large-radius jet masses is used to distinguish the signal from background, as it effectively captures the features of high jet multiplicity and high interaction energy. No significant excess of data over the background predictions is observed. Gluinos in this model have been excluded for masses below 1890 GeV at 95% confidence level." CMS Collaboration, "Search for new physics using single-lepton events with high multiplicities of jets and b jets in proton-proton collisions at s√ = 13 TeV" arXiv:2606.09567 (June 8, 2026) (Submitted to the Journal of High Energy Physics)
Other SUSY exclusions. https://dispatchesfromturtleisland.blogspot.com/2026/03/susy-excluded-up-to-tev-scale.html
Post a Comment