BARYONIC SUM RULES IN THE NEXT-TO-LEADING ORDER IN αs

1991 ◽  
Vol 06 (11) ◽  
pp. 2025-2034 ◽  
Author(s):  
A.A. OVCHINNIKOV ◽  
A.A. PIVOVAROV ◽  
L.R. SURGULADZE
Keyword(s):  
Experimental Data ◽  
Operator Product Expansion ◽  
Sum Rules ◽  
Operator Product ◽  
Leading Order ◽  
Perturbative Corrections

The perturbative corrections of order αs to the coefficient functions of the operator product expansion for the baryonic correlator are calculated. These corrections change considerably the numerical values of the mass and residue for the proton extracted from the sum rules and improve the agreement between the theoretical estimates and experimental data.

scholarly journals Analysis of the X(3842) as a D-wave charmonium meson

2019 ◽  
Vol 34 (26) ◽  
pp. 1950151
Author(s):  
Guo-Liang Yu ◽  
Zhi-Gang Wang
Keyword(s):  
Experimental Data ◽  
Operator Product Expansion ◽  
Mass Formula ◽  
Decay Constant ◽  
Sum Rules ◽  
Lhcb Collaboration ◽  
Operator Product ◽  
Strong Decay ◽  
State Formula ◽  
Vacuum Condensates

In this paper, we assign the newly reported state [Formula: see text] to be a [Formula: see text]-wave [Formula: see text] meson, and study its mass and decay constant with QCD sum rules by considering the contributions of vacuum condensates up to dimension-6 in the operator product expansion. The predicted mass [Formula: see text] GeV is in agreement with the experimental data [Formula: see text] MeV from the LHCb collaboration. This result supports assigning [Formula: see text] as the [Formula: see text] charmonium meson. In this case, its predicted strong decay width with the [Formula: see text] decay model is compatible with the experimental data.

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 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 Isgur–Wise functions, Bjorken–Uraltsev sum rules and their Lorentz group interpretation

2015 ◽  
Vol 30 (10) ◽  
pp. 1543008
Author(s):  
L. Oliver ◽  
J.-C. Raynal
Keyword(s):  
Lorentz Group ◽  
Operator Product Expansion ◽  
Positive Measure ◽  
Sum Rules ◽  
Integral Formula ◽  
Operator Product ◽  
Lorentz Transformations ◽  
Sum Rule ◽  
Heavy Quark Limit ◽  
Higher Derivatives

In the heavy quark limit of QCD, using the Operator Product Expansion and the non-forward amplitude, as proposed by Nikolai Uraltsev, we formulate sum rules that generalize Bjorken and Uraltsev sum rules. We recover the Uraltsev lower bound for the slope of the Isgur–Wise (IW) function, that we generalize to higher derivatives. We show that these results have a clear interpretation in terms of the Lorentz group, since the IW function is given by an overlap between the initial and final light clouds, related by Lorentz transformations. Both the Lorentz group and the Sum Rules approaches are equivalent. Moreover, we formulate an integral representation of the IW function with a positive measure. Inverting this integral formula, we obtain the measure in terms of the IW function, allowing one to formulate criteria to decide if a given ansatz for the IW function is compatible or not with the sum rule constraints. We compare these theoretical constraints to some forms proposed in the literature.

scholarly journals PION TRANSITION FORM FACTOR AT THE TWO-LOOP LEVEL VIS-À-VIS EXPERIMENTAL DATA

2009 ◽  
Vol 24 (35n37) ◽  
pp. 2858-2867 ◽  
Author(s):  
S. V. MIKHAILOV ◽  
N. G. STEFANIS
Keyword(s):  
Experimental Data ◽  
Perturbation Theory ◽  
Form Factor ◽  
Light Cone ◽  
Transition Form Factor ◽  
Sum Rules ◽  
Leading Order ◽  
Transition Form ◽  
Qcd Sum Rules ◽  
Theoretical Results

We use light-cone QCD sum rules to calculate the pion-photon transition form factor, taking into account radiative corrections up to the next-to-next-to-leading order of perturbation theory. We compare the obtained predictions with all available experimental data from the CELLO, CLEO, and the BaBar Collaborations. We point out that the BaBar data are incompatible with the convolution scheme of QCD, on which our predictions are based, and can possibly be explained only with a violation of the factorization theorem. We pull together recent theoretical results and comment on their significance.

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 Estimation of Nucleon D-Term in QCD

Particles ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 357-364 ◽  
Author(s):  
Igor V. Anikin
Keyword(s):  
Experimental Data ◽  
Form Factor ◽  
Light Cone ◽  
Sum Rules ◽  
Leading Order

Using the light-cone sum rules at leading order, we present an approach to perform the preliminary upper estimation for the nucleon gravitational form factor D ( t ) (D-term contribution). Comparison with the experimental data and with the results of different models is discussed.

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