RT Journal Article T1 Spontaneous mass generation and the small dimensions of the Standard Model gauge groups U(1), SU(2) and SU(3) A1 García Fernández, Guillermo A1 Guerrero Rojas, Jesús A1 Llanes Estrada, Felipe José AB The gauge symmetry of the Standard Model is SU(3)_(c) x SU(2)_(L) x U(1)_(Y) for unknown reasons. One aspect that can be addressed is the low dimensionality of all its subgroups. Why not much larger groups like SU(7), or for that matter, SP(38) or E7? We observe that fermions charged under large groups acquire much bigger dynamical masses, all things being equal at a high e.g. GUT scale, than ordinary quarks. Should such multicharged fermions exist, they are too heavy to be observed today and have either decayed early on (if they couple to the rest of the Standard Model) or become reliquial dark matter (if they don't). The result follows from strong antiscreening of the running coupling for those larger groups (with an appropriately small number of flavors) together with scaling properties of the Dyson-Schwinger equation for the fermion mass. PB Elsevier SN 0550-3213 YR 2017 FD 2017-02 LK https://hdl.handle.net/20.500.14352/17751 UL https://hdl.handle.net/20.500.14352/17751 LA eng NO © 2016 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license(http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3.Spanish Excellence Network on Hadronic Physics [FIS2014-57026-REDT]; [UCM:910309]; [MINECO:FPA2011-27853-C02-01]; [MINECO:FPA2014-53375-C2-1-P] NO Ministerio de Economía y Competitividad (MINECO) NO Universidad Complutense de Madrid NO Spanish Excellence Network on Hadronic Physics DS Docta Complutense RD 8 abr 2025