Abstract:We calculate the J/ΨD * D * form factor and coupling constant from QCD Sum Rules in the cases where J/Ψ and D * mesons are off-shell. The results show that this method is consistent and allows to extract the same coupling constant for the vertex.
“…This matching condition significantly reduces the freedom in the choice of the parameters f 1 , f 2 , Ketc. This procedure is enough to reduce the uncertainties and provides results consistent with the experimental values, as it was the case for the p D D * and y J D D * * studied in [164,165]. Even after the above mentioned improvement one might argue that the choice of the functional form,…”
Section: Qcd Input Parametersmentioning
confidence: 76%
“…. The squared invariant amplitude can be obtained from equation (165), using equations (166) and (167):…”
Section: Vector Charmonium Y Statesmentioning
confidence: 99%
“…where = ¢ + p p q and m J W , ( ¯) m J cc are given in equation (115). Following [101], the matrix elements in equation(165) are parametrized as:…”
In the past decade, due to the experimental observation of many charmonium-like states, there has been a revival of hadron spectroscopy. In particular, the experimental observation of charged charmonium-like, Z c states, and bottomonium-like, Z b states, represents a challenge since they can not be accommodated within the naive quark model. These charged states are good candidates of either tetraquark or molecular states and their observation motivated a vigorous theoretical activity. This is a rapidly evolving field with enormous amount of new experimental information. In this work, we review the current experimental progress and investigate various theoretical interpretations of these candidates of the multiquark states. The present review is written from the perspective of the QCD sum rules approach, where we present the main steps of concrete calculations and compare the results with other approaches and with experimental data.
“…This matching condition significantly reduces the freedom in the choice of the parameters f 1 , f 2 , Ketc. This procedure is enough to reduce the uncertainties and provides results consistent with the experimental values, as it was the case for the p D D * and y J D D * * studied in [164,165]. Even after the above mentioned improvement one might argue that the choice of the functional form,…”
Section: Qcd Input Parametersmentioning
confidence: 76%
“…. The squared invariant amplitude can be obtained from equation (165), using equations (166) and (167):…”
Section: Vector Charmonium Y Statesmentioning
confidence: 99%
“…where = ¢ + p p q and m J W , ( ¯) m J cc are given in equation (115). Following [101], the matrix elements in equation(165) are parametrized as:…”
In the past decade, due to the experimental observation of many charmonium-like states, there has been a revival of hadron spectroscopy. In particular, the experimental observation of charged charmonium-like, Z c states, and bottomonium-like, Z b states, represents a challenge since they can not be accommodated within the naive quark model. These charged states are good candidates of either tetraquark or molecular states and their observation motivated a vigorous theoretical activity. This is a rapidly evolving field with enormous amount of new experimental information. In this work, we review the current experimental progress and investigate various theoretical interpretations of these candidates of the multiquark states. The present review is written from the perspective of the QCD sum rules approach, where we present the main steps of concrete calculations and compare the results with other approaches and with experimental data.
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