1993/08/31 by Luis E. Ibáñez, Luis E. Ibanez · 2 citations
Physics and Astronomy · Social Sciences · #Gauge (firearms) #Gauge theory #Grand Unified Theory #Heterotic string theory #International Science and Diplomacy #Normalization (sociology) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #Standard Model (mathematical formulation) #String (physics) #Unification #hep-ph #hep-th
paper · pdf · doi:10.1016/0370-2693(93)91786-m
published as Phys.Lett. B318 (1993) 73-76 · 7 pages (1 figure available upon request, either as PS file or hard copy) FTUAM-35-93 harvmac
arxiv created 1993/08/31 · openalex publication_date 1993/11/01 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Standard (level one) heterotic string models with standard model gauge group predict the unification of SU(3) and SU(2) gauge couplings whereas the U(1) factor is unified modulo an unknown normalization factor k1. On the other hand the unification mass is known. I argue that this situation is quite analogous (though opposite) to that in SUSY-GUTs in which the U(1) normalization is known (k1=5/3) but the unification mass MX is unknown. I emphasize that k1 should be taken as a free parameter in the string approach (quite in the same way as MX is taken as a free parameter in SUSY-GUTs). If this is done, the success of the string approach concerning gauge coupling unification is comparable to that in SUSY-GUTs