2003/03/31 by Steven Abel, S. Abel, M. Masip +2 · 1 citation
Mathematics · Physics and Astronomy · #Black Holes and Theoretical Physics #Brane #Brane cosmology #Compactification (mathematics) #Cosmology and Gravitation Theories #Extra dimensions #Fermion #Gauge theory #Kaluza–Klein theory #Mathematics #Particle physics #Particle physics theoretical and experimental studies #Physics #Pure mathematics #String (physics) #String theory #Supersymmetry #Theoretical physics #hep-ph #hep-th
paper · pdf · doi:10.1088/1126-6708/2003/04/057
published as JHEP 0304 (2003) 057 · Matches the published version
openalex publication_date 2003/04/30 · arxiv created 2003/06/12 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Intersecting D-brane models provide an attractive explanation of family replication in the context of string theory. We show, however, that the localization of fermion families at different brane intersections in the extra dimensions introduces flavour changing neutral currents mediated by the Kaluza-Klein excitations of the gauge fields. This is a generic feature in these models, and it implies stringent bounds on the mass of the lightest Kaluza-Klein modes (becoming severe when the compactification radii are larger than the string length). We present the full string calculation of four-fermion interactions in models with intersecting D-branes, recovering the field theory result. This reveals other stringy sources of flavour violation, which give bounds that are complementary to the KK bounds (i.e. they become severe when the compactification radii are comparable to the string length). Taken together these bounds imply that the string scale is larger than Ms\gtrsim 102 TeV, implying that non-supersymmetric cases are phenomenologically disfavoured.