On properties of the exotic hadrons from QCD sum rules

Abstract

We discuss the specific features of extracting properties of the exotic polyquark hadrons (tetraquarks, pentaquarks) compared to the usual hadrons by the QCD sum-rule approach. In the case of the ordinary hadrons, already the one-loop leading-order correlation functions provide the bulk of the hadron observables, e.g., of the form factor; inclusion of radiative corrections modifies already nonzero one-loop contributions. In the case of an exotic hadron, the situation is qualitatively different: discussing strong decays of an exotic tetraquark meson, which provide the main contribution to its width, we show that the disconnected leading-order diagrams are not related to the tetraquark properties. For a proper description of the tetraquark decay width, it is mandatory to calculate specific radiative corrections which generate the connected diagrams.

arXiv comment6 pages, 3 figures, talk presented at "QCD@Work 2016 - International Workshop on Quantum Chromodynamics: Theory and Experiment" (27 - 30 June 2016, Martina Franca, Italy)

References in corpus (23)

• QCD at Low Energies
• New Charmonium States in QCD Sum Rules: a Concise Review
• Tetraquark Mesons in Large $N$ Quantum Chromodynamics
• An Illustrative Example of How Quark-Hadron Duality Might Work
• The $Z_b(10610)$ and $Z_b(10650)$ as axial-vector tetraquark states in the QCD sum rules
• Narrow Tetraquarks at Large N
• Decay constants of heavy pseudoscalar mesons from QCD sum rules
• Systematic uncertainties of hadron parameters obtained with QCD sum rules
• Quark structure of the pion and pion form factor
• Universal ${\tau }_{1/2}(y)$ Isgur-Wise Function at the Next-to-Leading Order in QCD Sum Rules
• The Isgur-Wise Function to $O({\alpha }_s)$ from Sum Rules in the Heavy Quark Effective Theory
• Extraction of ground-state decay constant from dispersive sum rules: QCD vs potential models
• Pion form factor at spacelike momentum transfers from local-duality QCD sum rule
• A QCD sum rule calculation of the $X^{\pm }(5568)\to B_s^0{\pi }^{\pm }$ decay width
• Accuracy of bound-state form factors extracted from dispersive sum rules
• Effective continuum threshold for vacuum-to-bound-state correlators
• Quantum-Number Exotic Tetraquarks at Large $N_c$ in QCD(AS)
• The puzzle of the π-> γγ* transition form factor
• Quark-hadron duality and hadron properties from correlators of pseudoscalar and axial currents
• On the ${\gamma }^{\ast }\gamma \to \pi (\eta ,{\eta }^{\prime })$ transition form factors
• Accuracy of the pion elastic form factor extracted from a local-duality sum rule
• Pion form factor and QCD sum rules: case of pseudoscalar current
• The ${\gamma }^{\ast }{\gamma }^{\ast }\to {\eta }_c$ transition form factor