Are there tetraquarks at large Nc in QCD(F)?

Thomas D. Cohen, Richard Lebed

Research output: Contribution to journalArticle

31 Scopus citations


Weinberg recently pointed out a flaw in the standard argument that large Nc QCD with color-fundamental quarks [QCD(F)] cannot yield narrow tetraquark states. In particular, he observed that the argument does not rule out narrow tetraquarks associated with the leading-order connected diagrams; such tetraquarks would have a width scaling as Nc-1. It is shown here, however, that while the standard analysis of tetraquarks does not rule them out, a more thorough analysis rules out quantum-number exotic tetraquarks associated with the leading-order connected diagrams. This analysis is based entirely on conventional assumptions used in large Nc physics applied to the analytic properties of meson-meson scattering. Our result implies that one of three possibilities must be true: (i) quantum-number exotic tetraquarks do not exist at large Nc; (ii) quantum-number exotic tetraquarks exist, but are associated with subleading connected diagrams and have anomalously small widths that scale as Nc-2 or smaller; or (iii) the conventional assumptions used in large Nc analysis are inadequate.

Original languageEnglish (US)
Article number016001
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number1
StatePublished - Jul 1 2014


ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)

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