scholarly journals SCALAR NONETS IN POLE-DOMINATED QCD SUM RULES

2008 ◽  
Vol 23 (27n30) ◽  
pp. 2230-2233
Author(s):  
TORU KOJO ◽  
DAISUKE JIDO
Keyword(s):  
Operator Product Expansion ◽  
Quark Mass ◽  
Sum Rules ◽  
Operator Product ◽  
Qcd Sum Rules ◽  
Current Quark Mass ◽  
Pole Dominance ◽  
Light Scalar ◽  
Current Quark

The light scalar nonets are studied using the QCD sum rules for the tetraquark operators. The operator product expansion for the correlators is calculated up to dimension 12 and this enables us to perform analyses retaining sufficient pole-dominance. To classify the light scalar nonets, we investigate the dependence on current quark mass and flavor dynamics. Especially, to examine the latter, we study separately SU(3) singlet and octet states, and show that the number of annihilation diagrams is largely responsible for their differences, which is also the case even after the inclusion of the finite quark mass. Our results support the tetraquark picture for isosinglets, while that for octets is not conclusive yet.

scholarly journals Analysis of the D̄Σc, D̄Σc∗, D̄∗Σc and D̄∗Σc∗ pentaquark molecular states with QCD sum rules

2019 ◽  
Vol 34 (19) ◽  
pp. 1950097 ◽  
Author(s):  
Zhi-Gang Wang
Keyword(s):  
Operator Product Expansion ◽  
Sum Rules ◽  
Molecular State ◽  
Operator Product ◽  
Qcd Sum Rules ◽  
Dimension Formula ◽  
Vacuum Condensates

In this paper, we study the [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] pentaquark molecular states with the QCD sum rules by carrying out the operator product expansion up to the vacuum condensates of dimension [Formula: see text] in a consistent way. The present calculations support assigning the [Formula: see text] to be the [Formula: see text] pentaquark molecular state with [Formula: see text], assigning the [Formula: see text] to be the [Formula: see text] pentaquark molecular state with [Formula: see text], assigning the [Formula: see text] to be the [Formula: see text] pentaquark molecular state with [Formula: see text] or the [Formula: see text] pentaquark molecular state with [Formula: see text]. Special attention is paid to the operator product expansion.

scholarly journals ON THE QCD SUM RULE DETERMINATION OF THE STRANGE QUARK MASS

2001 ◽  
Vol 16 (supp01b) ◽  
pp. 588-590 ◽  
Author(s):  
NELLO PAVER
Keyword(s):  
Spectral Function ◽  
Quark Mass ◽  
Strange Quark ◽  
Sum Rules ◽  
Sum Rule ◽  
Strange Quark Mass ◽  
Current Quark Mass ◽  
Current Quark

I briefly review recent QCD Sum Rules determinations of the strange current quark mass, based on the analysis of the two-point ΔS=1 scalar correlators and discuss, in particular, the role of resonances and non-resonant background in the spectral function.

scholarly journals Hidden-Beauty Broad Resonance Yb(10890) in Thermal QCD

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
J. Y. Süngü ◽  
A. Türkan ◽  
H. Dağ ◽  
E. Veli Veliev
Keyword(s):  
Critical Temperature ◽  
Finite Temperature ◽  
Operator Product Expansion ◽  
Sum Rules ◽  
Operator Product ◽  
Broad Resonance ◽  
Qcd Sum Rules ◽  
Pole Residue

In this work, the mass and pole residue of resonance Yb is studied by using QCD sum rules approach at finite temperature. Resonance Yb is described by a diquark-antidiquark tetraquark current, and contributions to operator product expansion are calculated by including QCD condensates up to dimension six. Temperature dependencies of the mass mYb and the pole residue λYb are investigated. It is seen that near a critical temperature (Tc≃190  MeV), the values of mYb and λYb decrease to 87% and to 44% of their values at vacuum.

scholarly journals Analysis of the Pc(4312), Pc(4440), Pc(4457) and related hidden-charm pentaquark states with QCD sum rules

2020 ◽  
Vol 35 (01) ◽  
pp. 2050003 ◽  
Author(s):  
Zhi-Gang wang
Keyword(s):  
Mass Spectrum ◽  
Ground State ◽  
Operator Product Expansion ◽  
Sum Rules ◽  
Operator Product ◽  
Qcd Sum Rules ◽  
Type Formula ◽  
Vacuum Condensates

In this paper, we restudy the ground state mass spectrum of the diquark–diquark–antiquark-type [Formula: see text] pentaquark states with the QCD sum rules by carrying out the operator product expansion up to the vacuum condensates of dimension 13 in a consistent way. The predicted masses support assigning the [Formula: see text] to be the hidden-charm pentaquark state with [Formula: see text], assigning the [Formula: see text] to be the hidden-charm pentaquark state with [Formula: see text], [Formula: see text] or [Formula: see text], assigning the [Formula: see text] to be the hidden-charm pentaquark state with [Formula: see text] or [Formula: see text].

scholarly journals Does vacuum saturation work for the higher-dimensional vacuum condensates in the QCD sum rules?

2021 ◽  
Author(s):  
Zhi-Gang Wang
Keyword(s):  
Operator Product Expansion ◽  
Sum Rules ◽  
Operator Product ◽  
Qcd Sum Rules ◽  
Text Type ◽  
Factorization Approximation ◽  
Vacuum Saturation ◽  
Higher Dimensional ◽  
Vacuum Condensates ◽  
Saturation Approximation

In the QCD sum rules for the tetraquark (molecular) states, the higher-dimensional vacuum condensates play an important role in extracting the tetraquark masses. We carry out the operator product expansion up to the vacuum condensates of dimension-10 and observe that the vacuum condensates of dimensions 6, 8 and 10 have the same expressions but opposite signs for the [Formula: see text]-type and [Formula: see text]-type four-quark currents, which make their influences distinguishable, and they are excellent channels to examine the vacuum saturation approximation. We introduce a parameter [Formula: see text] to parametrize the derivation from the vacuum saturation or factorization approximation, and choose two sets of parameters to examine the influences on the predicted tetraquark masses, which can be confronted to the experimental data in the future. In all the channels, smaller value of the [Formula: see text] leads to better convergent behavior in the operator product expansion, which favors the vacuum saturation approximation.

scholarly journals Tetraquark state candidates: Y(4140), Y(4274) and X(4350)

2015 ◽  
Vol 30 (01) ◽  
pp. 1550004 ◽  
Author(s):  
Zhi-Gang Wang ◽  
Ye-Fan Tian
Keyword(s):  
Operator Product Expansion ◽  
Sum Rules ◽  
Numerical Results ◽  
Operator Product ◽  
Tetraquark State ◽  
Spectral Densities ◽  
Qcd Sum Rules ◽  
Tensor Formula ◽  
Vacuum Condensates

In this paper, we tentatively assign the Y(4140), Y(4274) and X(4350) to be the scalar and tensor [Formula: see text] tetraquark states, respectively, and study them with the QCD sum rules. In the operator product expansion, we take into account the vacuum condensates up to dimension-10. In calculations, we use the formula [Formula: see text] to determine the energy scales of the QCD spectral densities. The numerical results favor assigning the Y(4140) to be the JPC = 2++ diquark–antidiquark type tetraquark state, and disfavor assigning the Y(4274) and X(4350) to be the 0++ or 2++ tetraquark states.

scholarly journals Analysis of the triply heavy baryon states with the QCD sum rules

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Zhi-Gang Wang
Keyword(s):  
Mass Spectrum ◽  
Ground State ◽  
Operator Product Expansion ◽  
Sum Rules ◽  
Heavy Baryon ◽  
Operator Product ◽  
Qcd Sum Rules ◽  
Gluon Condensates ◽  
First Time ◽  
Vacuum Condensates

AbstractIn this article, we reexamine the mass spectrum of the ground state triply heavy baryon states with the QCD sum rules by carrying out the operator product expansion up to the vacuum condensates of dimension 6 in a consistent way and preforming a novel analysis. It is for the first time to take into account the three-gluon condensates in the QCD sum rules for the triply heavy baryon states.

scholarly journals Triply-charmed hexaquark states with the QCD sum rules

2020 ◽  
Vol 35 (14) ◽  
pp. 2050073
Author(s):  
Zhi-Gang Wang
Keyword(s):  
Spectral Density ◽  
Ground State ◽  
Operator Product Expansion ◽  
Sum Rules ◽  
Axial Vector ◽  
Energy Scale ◽  
Operator Product ◽  
Pole Contribution ◽  
Qcd Sum Rules ◽  
The Masses

In this paper, we construct the charmed-diquark–charmed-diquark–charmed-diquark-type current to study the axial vector triply-charmed hexaquark state with the QCD sum rules in details. In calculations, we take the energy scale formula [Formula: see text] to choose the pertinent energy scale of the QCD spectral density so as to enhance the pole contribution and improve the convergent behavior of the operator product expansion. If the spin-breaking effects are small for the triply-charmed hexaquark states, the ground state hexaquark states with [Formula: see text], [Formula: see text] and [Formula: see text] are estimated to have the masses about 5.8 GeV and narrow widths.

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