Light-front QCD. II. Two-component theory

Zhang, Wei Min; Harindranath, A.

doi:10.1103/physrevd.48.4881

Cited by 105 publications

(132 citation statements)

References 42 publications

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“…Note that in the light-cone gaugen · A n,q = 0 these Feynman rules are the complete set, since interactions of a collinear quark with three or more collinear gluons vanish. In this gauge similar Feynman rules for collinear gluons have been obtained in the framework of light cone QCD [17]. However, the Feynman rules in Fig.…”

Section: The Effective Theorymentioning

confidence: 98%

An effective field theory for collinear and soft gluons: Heavy to light decays

et al. 2001

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We construct the Lagrangian for an effective theory of highly energetic quarks with energy Q, interacting with collinear and soft gluons. This theory has two low energy scales, the transverse momentum of the collinear particles, p ⊥ , and the scale p 2 ⊥ /Q. The heavy to light currents are matched onto operators in the effective theory at one-loop and the renormalization group equations for the corresponding Wilson coefficients are solved. This running is used to sum Sudakov logarithms in inclusive B → X s γ and B → X u ℓν decays. We also show that the interactions with collinear gluons preserve the relations for the soft part of the form factors for heavy to light decays found by Charles et al., establishing these relations in the large energy limit of QCD.

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Section: The Effective Theorymentioning

confidence: 98%

An effective field theory for collinear and soft gluons: Heavy to light decays

et al. 2001

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“…[21]. In this paper, however, we choose a representation (1.4) from which it is easy to extract information of the 1+1 dimensional results.…”

Section: Discussionmentioning

confidence: 99%

Dynamical chiral symmetry breaking on the light front. II. The Nambu–Jona-Lasinio model

Itakura

Maedan

2000

Phys. Rev. D

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An investigation of dynamical chiral symmetry breaking on the light front is made in the NambuJona-Lasinio model with one flavor and N colors. Analysis of the model suffers from extraordinary complexity due to the existence of a "fermionic constraint," i.e., a constraint equation for the bad spinor component. However, to solve this constraint is of special importance. In classical theory, we can exactly solve it and then explicitly check the property of "light-front chiral transformation." In quantum theory, we introduce a bilocal formulation to solve the fermionic constraint by the 1/N expansion. Systematic 1/N expansion of the fermion bilocal operator is realized by the boson expansion method. The leading (bilocal) fermionic constraint becomes a gap equation for a chiral condensate and thus if we choose a nontrivial solution of the gap equation, we are in the broken phase. As a result of the nonzero chiral condensate, we find unusual chiral transformation of fields and nonvanishing of the light-front chiral charge. A leading order eigenvalue equation for a single bosonic state is equivalent to a leading order fermion-antifermion bound-state equation. We analytically solve it for scalar and pseudoscalar mesons and obtain their light-cone wavefunctions and masses. All of the results are entirely consistent with those of our previous analysis on the chiral Yukawa model.

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“…As stated before, the cutoff at x 0 is imposed for the numerical calculation and has a small effect on the result. If, instead of imposing a cutoff on transverse momentum, , we imposed a cutoff on the invariant mass [15], then the divergences at x 1 would have been regulated by a nonzero photon mass [28]. The DVCS amplitude at x 1 also receives a contribution from the single-particle sector of the Fock space [4,16,17,21], which we did not take into account.…”

Section: Calculation Of the Fourier Transformmentioning

confidence: 99%

Hadron optics in three-dimensional invariant coordinate space from deeply virtual Compton scattering

et al. 2007

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The Fourier transform of the deeply virtual Compton scattering amplitude (DVCS) with respect to the skewness parameter Q 2 =2p q can be used to provide an image of the target hadron in the boostinvariant variable , the coordinate conjugate to light-front time t z=c. As an illustration, we construct a consistent covariant model of the DVCS amplitude and its associated generalized parton distributions using the quantum fluctuations of a fermion state at one loop in QED, thus providing a representation of the light-front wave functions (LFWFs) of a lepton in space. A consistent model for hadronic amplitudes can then be obtained by differentiating the light-front wave functions with respect to the bound-state mass. The resulting DVCS helicity amplitudes are evaluated as a function of and the impact parameterb ? , thus providing a light-front image of the target hadron in a frame-independent threedimensional light-front coordinate space. Models for the LFWFs of hadrons in 3 1 dimensions displaying confinement at large distances and conformal symmetry at short distances have been obtained using the AdS/CFT method. We also compute the LFWFs in this model in invariant three-dimensional coordinate space. We find that, in the models studied, the Fourier transform of the DVCS amplitudes exhibit diffraction patterns. The results are analogous to the diffractive scattering of a wave in optics where the distribution in measures the physical size of the scattering center in a one-dimensional system.

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Light-front QCD. II. Two-component theory

Cited by 105 publications

References 42 publications

An effective field theory for collinear and soft gluons: Heavy to light decays

An effective field theory for collinear and soft gluons: Heavy to light decays

Dynamical chiral symmetry breaking on the light front. II. The Nambu–Jona-Lasinio model

Hadron optics in three-dimensional invariant coordinate space from deeply virtual Compton scattering

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