Compact Flavour-Exotic Tetraquarks in Large-Νc QCD - To Be or Not to Be?

Dmitri Melikhov (Corresponding author), Wolfgang Lucha, Hagop Sazdjian

Publications: Contribution to journalMeeting abstract/Conference paperPeer Reviewed

Abstract

We analyse exotic tetraquark mesons - bound states formed by two quarks and two antiquarks - for the specific case of four different quark flavours within the framework of a well-defined limit of quantum chromodynamics characterized by the correlated growth without bound of the number of colour degrees of freedom and approach to zero of the coupling constant of the strong interactions. On the one hand, the assumption that the tetraquarks of the kind defined above show up, as poles in the amplitudes for the scattering of two ordinary mesons with flavour quantum numbers that match those of these tetraquarks, already at lowest possible order in an expansion in inverse powers of the number of colours implies the existence of two types of flavour-exotic tetraquarks, distinguishable by their dominant transitions to two ordinary mesons. On the other hand, we are aware of merely a single, unique colour-singlet arrangement of two quarks and two antiquarks capable of tolerating a compact flavour-exotic tetraquark, a bound state of colour-antisymmetric diquark and antidiquark. In view of these two clearly contradictory observations, we are led to the plausible conclusion that, within the considered limiting case of quantum chromodynamics, a conceivable explanation of the riddle might consist in the non-existence of any flavour-exotic tetraquarks in form of narrow states.
Original languageEnglish
Article number087
Number of pages7
JournalProceedings of Science (PoS)
Volume336
DOIs
Publication statusPublished - 26 Sep 2019
EventXIII Quark Confinement and the Hadron Spectrum - Confinement2018 - Maynooth, Ireland
Duration: 31 Jul 20186 Aug 2018

Austrian Fields of Science 2012

  • 103012 High energy physics

Keywords

  • hep-ph

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