Are there narrow flavor-exotic tetraquarks in large- Ν<sub>c</sub> QCD?

Wolfgang Lucha, Dmitri Melikhov, Hagop Sazdjian

A salient feature shared by all tetraquark candidates observed in experiment is the absence of flavor-exotic states of the type ābcd, with four different quark flavors. This phenomenon may be understood from the properties of large-Nc QCD. On the one hand, previous work shows that consistency conditions for flavor-exotic Green functions, potentially containing these tetraquark poles, require the existence of two tetraquarks TA and TB: Each of them should decay dominantly via a single two-meson channel, TA→MābMcd and TB→MādMcb, with suppressed rates TA→MādMcb and TB→MābMcd. On the other hand, we have at hand only one diquark-antidiquark flavor structure (āc)(bd) that might produce a compact tetraquark bound state. Taking into account that the diquark-antidiquark structure is the only viable candidate for a compact tetraquark state, one concludes that it is impossible to obtain two different narrow tetraquarks decaying dominantly into distinct two-meson channels. This contradiction suggests that large-Nc QCD does not support the existence of narrow flavor-exotic tetraquarks. This argument does not rule out the possible existence of broad molecular-type flavor-exotic states or of molecular-type bound states lying very close to the two-meson thresholds.

Particle Physics
External organisation(s)
Österreichische Akademie der Wissenschaften (ÖAW), Lomonosov Moscow State University (MSU), Universität Wien, Univ Paris Diderot, Centre National de la Recherche Scientifique (CNRS), CNRS - National Institute for Biology (INSB), UDICE-French Research Universities, Universite de Paris, CNRS, Lab Epigenet & Destin Cellulaire, UMR7216
Physical Review D
Publication date
Peer reviewed
Austrian Fields of Science 2012
103034 Particle physics
ASJC Scopus subject areas
Physics and Astronomy (miscellaneous)
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