TY - JOUR
T1 - Diquarks and antiquarks in exotics
T2 - A ménage à trois and a ménage à quatre
AU - Karliner, Marek
AU - Lipkin, Harry J.
N1 - Funding Information:
The research of M.K. was supported in part by a grant from the Israel Science Foundation administered by the Israel Academy of Sciences and Humanities.
PY - 2006/7/6
Y1 - 2006/7/6
N2 - A ménage à trois is very different from an ordinary family. Similarly, exotic hadrons with both qq and q over(q, ̄) pairs have important color-space correlations that are completely absent in ordinary mesons and baryons. The presence of both types of pairs requires attention to the basic QCD physics that the q over(q, ̄) interaction is much stronger than the qq interaction. This new physics in multiquark systems produces color structures totally different from those of normal hadrons, for example the ud system is utterly unlike the ud diquark in the uds Λ baryon. The color-space correlations produce unusual experimental properties in tetraquarks with heavy quark pairs which may be relevant for newly discovered mesons like the X (3872) resonance. Tetraquark masses can be below the two-meson threshold for sufficiently high quark masses. A simple model calculation shows the b q over(b, ̄) over(u, ̄) and b q over(c, ̄) over(q, ̄) tetraquarks below the B over(B, ̄) and B over(D, ̄) thresholds. Some of these states have exotic electric charge and their decays might have striking signatures involving monoenergetic photons and/or pions.
AB - A ménage à trois is very different from an ordinary family. Similarly, exotic hadrons with both qq and q over(q, ̄) pairs have important color-space correlations that are completely absent in ordinary mesons and baryons. The presence of both types of pairs requires attention to the basic QCD physics that the q over(q, ̄) interaction is much stronger than the qq interaction. This new physics in multiquark systems produces color structures totally different from those of normal hadrons, for example the ud system is utterly unlike the ud diquark in the uds Λ baryon. The color-space correlations produce unusual experimental properties in tetraquarks with heavy quark pairs which may be relevant for newly discovered mesons like the X (3872) resonance. Tetraquark masses can be below the two-meson threshold for sufficiently high quark masses. A simple model calculation shows the b q over(b, ̄) over(u, ̄) and b q over(c, ̄) over(q, ̄) tetraquarks below the B over(B, ̄) and B over(D, ̄) thresholds. Some of these states have exotic electric charge and their decays might have striking signatures involving monoenergetic photons and/or pions.
UR - http://www.scopus.com/inward/record.url?scp=33744982640&partnerID=8YFLogxK
U2 - 10.1016/j.physletb.2006.05.032
DO - 10.1016/j.physletb.2006.05.032
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AN - SCOPUS:33744982640
SN - 0370-2693
VL - 638
SP - 221
EP - 228
JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
IS - 2-3
ER -