Tetraquark and twomeson states at large N_{c}
Abstract
Considering fourpoint correlation functions of colorsinglet quark bilinears, we investigate, in the largeN_{c} limit of QCD, the subleading diagrams that involve, in the schannel of mesonmeson scattering amplitudes, twoquarktwoantiquark intermediate states. The latter contribute, together with gluon exchanges, to the formation, at the hadronic level, of twomeson and tetraquark intermediate states. It is shown that the twomeson contributions, which are predictable, in general, from leadingorder N_{c}behaviors, consistently satisfy the constraints resulting from the 1/N_{c} expansion procedure and thus provide a firm basis for the extraction of tetraquark properties from N_{c}subleading diagrams. We find that, in general, tetraquarks, if they exist in compact form, should have narrow decay widths, of the order of N_{c}^{2}. For the particular case of exotic tetraquarks, involving four different quark flavors, two different types of tetraquark are needed, each having a preferred decay channel, to satisfy the consistency constraints.
 Publication:

European Physical Journal C
 Pub Date:
 December 2017
 DOI:
 10.1140/epjc/s100520175437x
 arXiv:
 arXiv:1710.08316
 Bibcode:
 2017EPJC...77..866L
 Keywords:

 High Energy Physics  Phenomenology
 EPrint:
 23 pages, 24 figures. A few clarifying paragraphs, two figures and one reference have been added