Light-Cone Operator-Product Expansions Revisited: I

2004 ◽  
Vol 138 (3) ◽  
pp. 370-382 ◽  
Author(s):  
O. I. Zavialov
Keyword(s):  
Light Cone ◽  
Operator Product

NEW SCALING VARIABLE FROM LIGHT-CONE PERTURBATION THEORY

1991 ◽  
Vol 06 (03) ◽  
pp. 345-363 ◽  
Author(s):  
BO-QIANG MA ◽  
JI SUN
Keyword(s):  
Perturbation Theory ◽  
Power Law ◽  
Light Cone ◽  
Operator Product Expansion ◽  
Free Field ◽  
Field Operator ◽  
Order Effect ◽  
Operator Product ◽  
Bjorken Scaling ◽  
Twist Effect

We argue from both the quark language and the free field light-cone expansion in light-cone perturbation theory that the constraint of overall “energy” conservation in deep inelastic lepton-nucleon scattering yields a similar new scaling variable xp, which reduces to the Weizmann variable, the Bloom-Gilman variable and the Bjorken variable at some approximations. The xp rescaling is expected to be a good scaling variable, and hence gives strong power-law type corrections to the deviations of Bjorken scaling. An understanding of this xp rescaling from both the free field operator product expansion (OPE) and the ordinary OPE is also given, indicating it is likely a higher order effect in the coefficient functions, i.e. it does not belong to the higher twist effect. Therefore this xp rescaling is likely a new effect contributing to the power-law type corrections.

scholarly journals The D∗Dπ and B∗Bπ couplings from light-cone sum rules

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Alexander Khodjamirian ◽  
Blaženka Melić ◽  
Yu-Ming Wang ◽  
Yan-Bing Wei
Keyword(s):  
Correlation Function ◽  
Lattice Qcd ◽  
Light Cone ◽  
Sum Rules ◽  
Analytical Form ◽  
Operator Product ◽  
Decay Constants ◽  
Meson Coupling ◽  
Double Dispersion ◽  
First Time

Abstract We revisit the calculation of the strong couplings D∗Dπ and B∗Bπ from the QCD light-cone sum rules using the pion light-cone distribution amplitudes. The accuracy of the correlation function, calculated from the operator product expansion near the light-cone, is upgraded by taking into account the gluon radiative corrections to the twist-3 terms. The double spectral density of the correlation function, including the twist-2, 3 terms at $$ \mathcal{O}\left({\alpha}_s\right) $$ O α s and the twist-4 LO terms, is presented in an analytical form for the first time. This form allows us to use various versions of the quark-hadron duality regions in the double dispersion relation underlying the sum rules. We predict $$ {g}_{D^{\ast } D\pi}={14.1}_{-1.2}^{+1.3} $$ g D ∗ Dπ = 14.1 − 1.2 + 1.3 and $$ {g}_{B^{\ast } B\pi}={30.0}_{-2.4}^{+2.6} $$ g B ∗ Bπ = 30.0 − 2.4 + 2.6 when the decay constants of heavy mesons entering the light-cone sum rule are taken from lattice QCD results. We compare our results with the experimental value for the charmed meson coupling and with the lattice QCD calculations.

scholarly journals Operator product expansions near the light cone

1971 ◽  
Vol 27 (3) ◽  
pp. 541-567 ◽  
Author(s):  
Richard A. Brandt ◽  
Giuliano Preparata
Keyword(s):  
Light Cone ◽  
Operator Product

Light-cone QCD on the lattice

2000 ◽  
Vol 83-84 (1-3) ◽  
pp. 116-120 ◽  
Author(s):  
S Dalley
Keyword(s):  
Light Cone

scholarly journals Standard Model prediction of the Bc lifetime

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Jason Aebischer ◽  
Benjamín Grinstein
Keyword(s):  
Standard Model ◽  
Model Prediction ◽  
Strange Quark ◽  
Standard Model Prediction ◽  
New Physics ◽  
Operator Product ◽  
Special Focus ◽  
Third Order ◽  
Clear Cut ◽  
The Standard Model

Abstract Applying an operator product expansion approach we update the Standard Model prediction of the Bc lifetime from over 20 years ago. The non-perturbative velocity expansion is carried out up to third order in the relative velocity of the heavy quarks. The scheme dependence is studied using three different mass schemes for the $$ \overline{b} $$ b ¯ and c quarks, resulting in three different values consistent with each other and with experiment. Special focus has been laid on renormalon cancellation in the computation. Uncertainties resulting from scale dependence, neglecting the strange quark mass, non-perturbative matrix elements and parametric uncertainties are discussed in detail. The resulting uncertainties are still rather large compared to the experimental ones, and therefore do not allow for clear-cut conclusions concerning New Physics effects in the Bc decay.

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