COMMENTS ON QCD SUM-RULE CALCULATIONS OF EXCLUSIVE TWO-BODY DECAYS OF CHARMED MESONS

1989 ◽  
Vol 04 (09) ◽  
pp. 877-883 ◽  
Author(s):  
LING-LIE CHAU ◽  
HAI-YANG CHENG
Keyword(s):  
Experimental Data ◽  
Sum Rules ◽  
Theoretical Calculations ◽  
Charmed Mesons ◽  
Qcd Sum Rules ◽  
Generic Structure ◽  
Sum Rule ◽  
Quark Diagram ◽  
Model Independent ◽  
Decays Of Charmed Mesons

Exclusive two-body decay amplitudes of charmed mesons evaluated by Blok and Shifman (BS) using QCD sum rules are analyzed using the model-independent quark-diagram scheme, which helps to pin point the generic structure of the BS calculations, and their difficulties when compared with the experimental data. We also point out what experimental improvements on the data and which new data are most helpful in sharpening these comparisons. Some comments on possible ways of further improving the theoretical calculations are given.

scholarly journals The scalar and pseudoscalar hidden-charm tetraquark states with QCD sum rules

2018 ◽  
Vol 33 (14n15) ◽  
pp. 1850090
Author(s):  
Zun-Yan Di ◽  
Zhi-Gang Wang
Keyword(s):  
Experimental Data ◽  
Correlation Functions ◽  
Sum Rules ◽  
Qcd Sum Rules ◽  
Sum Rule ◽  
Rule Approach ◽  
Point Correlation ◽  
The Masses ◽  
Vacuum Condensates ◽  
Conserved Currents

Based on the diquark configuration, we construct the diquark–antidiquark interpolating tetraquark currents with [Formula: see text] and [Formula: see text], which can couple to the scalar and pseudoscalar tetraquark states, respectively, since they are not conserved currents. Then, we investigate their two-point correlation functions including the contributions of the vacuum condensates up to dimension-10 and extract the masses and pole residues of the tetraquark states with [Formula: see text] and [Formula: see text] through the QCD sum rule approach. The predicted masses can be confronted with the experimental data in the future. Moreover, we briefly discuss the possible decay patterns of the tetraquark states.

scholarly journals D*→ Dγ and B*→ Bγ as Derived from QCD Sum Rules

1997 ◽  
Vol 12 (39) ◽  
pp. 3027-3035 ◽  
Author(s):  
Shi-Lin Zhu ◽  
Ze-Sen Yang ◽  
W.-Y. P. Hwang
Keyword(s):  
Experimental Data ◽  
Sum Rules ◽  
Magnetic Moments ◽  
Radiative Decays ◽  
B Decays ◽  
Qcd Sum Rules ◽  
Independent Manner ◽  
Theoretical Predictions ◽  
Model Independent

We use the method of QCD sum rules in the presence of the external electromagnetic Fμν field to analyze radiative decays of charmed or bottomed mesons such as D*→ Dγ and B*→ Bγ, in a model-independent manner upon making use of the susceptibilities obtained previously from the study of baryon magnetic moments. Our predictions on D* decays agree very well with the experimental data. There are differences among the various theoretical predictions on B* decays and future experimental data should help to discriminate among the various predictions.

scholarly journals ANALYSIS OF THE $B \to K^*_2(1430), a_2(1320), f_2(1270)$ FORM-FACTORS WITH LIGHT-CONE QCD SUM RULES

2011 ◽  
Vol 26 (37) ◽  
pp. 2761-2782 ◽  
Author(s):  
ZHI-GANG WANG
Keyword(s):  
Experimental Data ◽  
Light Cone ◽  
B Meson ◽  
Sum Rules ◽  
Form Factors ◽  
Distribution Amplitude ◽  
Qcd Sum Rules ◽  
Line Shapes ◽  
The Future

In this paper, we study the [Formula: see text] form-factors with the light-cone QCD sum rules, where the B-meson light-cone distribution amplitudes are used. In calculations, we observe that the line-shapes of the B-meson light-cone distribution amplitude ϕ+(ω) have significant impacts on the values of the form-factors, and expect to obtain severe constraints on the parameters of the B-meson light-cone distribution amplitudes from the experimental data in the future.

scholarly journals REVIEW ON QCD SUM RULES CALCULATIONS FOR EXOTICS CHARMONIUM

2011 ◽  
Vol 02 ◽  
pp. 36-40
Author(s):  
MARINA NIELSEN
Keyword(s):  
Sum Rules ◽  
Mass Region ◽  
Qcd Sum Rules ◽  
Sum Rule ◽  
Rule Approach ◽  
New States

Many new states in the charmonium mass region were recently discovered by the BaBar, Belle and CDF Collaborations. We use the QCD Sum Rule approach to study the possible structure of some of these states.

scholarly journals ANALYSIS OF THE $B_q\to D_q(D_q^*)P$ AND $B_q\to D_q(D_q^*)V$ DECAYS WITHIN THE FACTORIZATION APPROACH IN QCD

2009 ◽  
Vol 24 (31) ◽  
pp. 5845-5860 ◽  
Author(s):  
K. AZIZI ◽  
R. KHOSRAVI ◽  
F. FALAHATI
Keyword(s):  
Experimental Data ◽  
Perturbative Qcd ◽  
Sum Rules ◽  
Branching Fraction ◽  
Form Factors ◽  
Transition Form ◽  
Qcd Sum Rules ◽  
Factorization Approach ◽  
Electroweak Penguin ◽  
Decay Widths

Using the factorization approach and considering the contributions of the current–current, QCD penguin and electroweak penguin operators at the leading approximation, the decay amplitudes and decay widths of [Formula: see text] and [Formula: see text] transitions, where q = u, d, s and P and V are pseudoscalar and vector mesons, are calculated in terms of the transition form factors of the Bq→Dq and [Formula: see text]. Having computed those form factors in three-point QCD sum rules, the branching fraction for these decays are also evaluated. A comparison of our results with the predictions of the perturbative QCD as well as the existing experimental data is presented.

scholarly journals Analysis of the Zc(4200) as axial-vector molecule-like state

2015 ◽  
Vol 30 (30) ◽  
pp. 1550168 ◽  
Author(s):  
Zhi-Gang Wang
Keyword(s):  
Experimental Data ◽  
Sum Rules ◽  
Axial Vector ◽  
Vector Current ◽  
Axial Vector Current ◽  
Qcd Sum Rules ◽  
Color Octet ◽  
Type Molecule

In this paper, we assume the [Formula: see text] as the color octet–octet type axial-vector molecule-like state, and construct the color octet–octet type axial-vector current to study its mass and width with the QCD sum rules. The numerical values [Formula: see text] and [Formula: see text] are consistent with the experimental data [Formula: see text] and [Formula: see text], and support assigning the [Formula: see text] to be the color octet–octet type molecule-like state with [Formula: see text]. Furthermore, we discuss the possible assignments of the [Formula: see text], [Formula: see text] and [Formula: see text] as the diquark–antidiquark type tetraquark states with [Formula: see text].

LIGHT QUARK MASSES FROM QCD SUM RULES

2013 ◽  
Vol 28 (26) ◽  
pp. 1360016 ◽  
Author(s):  
KARL SCHILCHER
Keyword(s):  
Quark Mass ◽  
Strange Quark ◽  
Sum Rules ◽  
Light Quark ◽  
Finite Energy ◽  
Qcd Sum Rules ◽  
Sum Rule ◽  
Quark Masses ◽  
Strange Quark Mass

Recent QCD sum rule determinations of the light quark masses are reviewed. In the case of the strange quark mass, possible uncertainties are discussed in the framework of finite energy sum rules.

scholarly journals THE SECOND MOMENT OF THE STRUCTURE FUNCTION FOR PSEUDOSCALAR MESONS IN QCD SUM RULES

1996 ◽  
Vol 05 (01) ◽  
pp. 121-129
Author(s):  
YOSHINORI NISHINO
Keyword(s):  
Structure Function ◽  
Sum Rules ◽  
Qcd Sum Rules ◽  
Sum Rule ◽  
Second Moment ◽  
Flavor Structure ◽  
Pseudoscalar Mesons

We calculate the second moment [Formula: see text] of the flavor-singlet structure function [Formula: see text] for the pion and the kaon in the framework of the QCD sum rule, and investigate how the results depend on their flavor structure (quark contents). Our calculations give similar values of [Formula: see text] for these two mesons as a result of the cancellation among several non-small factors.

scholarly journals Analysis of the heavy quarkonium states hc and hb with QCD sum rules

2014 ◽  
Vol 29 ◽  
pp. 1460233
Author(s):  
Zhi-Gang Wang ◽  
Shu-Yuan Guo
Keyword(s):  
Experimental Data ◽  
Sum Rules ◽  
P Wave ◽  
Heavy Quarkonium ◽  
Qcd Sum Rules ◽  
Decay Constants ◽  
Spin Singlet ◽  
Structure Formula ◽  
Quark Structure ◽  
The Masses

In this article, we take the tensor currents [Formula: see text] to interpolate the P-wave spin-singlet heavy quarkonium states hQ, and study the masses and decay constants with the Borel sum rules and moments sum rules. The masses and decay constants from the Borel sum rules and moments sum rules are consistent with each other, the masses are also consistent with the experimental data. The heavy quarkonium states hQ couple potentially to the tensor currents [Formula: see text], and have the quark structure ϵijkξ†σkζ besides the quark structure [Formula: see text].

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