scholarly journals Chiral light-front perturbation theory and the flavor dependence of the light-quark nucleon sea

2019 ◽  
Vol 100 (3) ◽  
Author(s):  
Mary Alberg ◽  
Gerald A. Miller
Keyword(s):  
Perturbation Theory ◽  
Light Quark ◽  
Light Front

Light front Hamiltonian for boson form of QED (1 + 1) in Pauli–Villars regularization

2019 ◽  
Vol 34 (21) ◽  
pp. 1950113
Author(s):  
V. A. Franke ◽  
M. Yu. Malyshev ◽  
S. A. Paston ◽  
E. V. Prokhvatilov ◽  
M. I. Vyazovsky
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Chiral Condensate ◽  
Light Front ◽  
Coupling Constants ◽  
Hamiltonian Approach ◽  
Chiral Perturbation ◽  
Dimensional Models ◽  
Villars Regularization ◽  
Ultraviolet Regularization

Light front (LF) Hamiltonian for QED in [Formula: see text] dimensions is constructed using the boson form of this model with additional Pauli–Villars-type ultraviolet regularization. Perturbation theory, generated by this LF Hamiltonian, is proved to be equivalent to usual covariant chiral perturbation theory. The obtained LF Hamiltonian depends explicitly on chiral condensate parameters which enter in a form of some renormalization of coupling constants. The obtained results can be useful when one attempts to apply LF Hamiltonian approach for [Formula: see text]-dimensional models like QCD.

scholarly journals Applications of AdS/CFT Duality to QCD

2006 ◽  
Vol 21 (04) ◽  
pp. 762-768 ◽  
Author(s):  
Stanley J. Brodsky ◽  
Guy F. de Téramond
Keyword(s):  
Scattering Amplitudes ◽  
Quantum Chromodynamics ◽  
Power Law ◽  
Mass Parameter ◽  
Light Quark ◽  
Form Factors ◽  
Light Front ◽  
Baryon Spectrum ◽  
Conformal Theory ◽  
Counting Rules

Even though quantum chromodynamics is a broken conformal theory, the AdS/CFT correspondence has led to important insights into the properties of QCD. For example, as shown by Polchinski and Strassler, dimensional counting rules for the power-law falloff of hadron scattering amplitudes follow from dual holographic models with conformal behavior at short distances and confinement at large distances. We find that one also obtains a remarkable representation of the entire light-quark meson and baryon spectrum, including all orbital excitations, based on only one mass parameter. We also show how hadron light-front wavefunctions and hadron form factors in both the space-like and time-like regions can be predicted.

scholarly journals Quark, pion and axial condensates in three-flavor finite isospin chiral perturbation theory

2021 ◽  
Vol 81 (5) ◽  
Author(s):  
Prabal Adhikari ◽  
Jens O. Andersen ◽  
Martin A. Mojahed
Keyword(s):  
Perturbation Theory ◽  
Lattice Qcd ◽  
Chiral Perturbation Theory ◽  
Strange Quark ◽  
Chemical Potential ◽  
Light Quark ◽  
Quark Condensate ◽  
Lattice Data ◽  
Chiral Perturbation ◽  
Good Agreement

AbstractWe calculate the light-quark condensate, the strange-quark condensate, the pion condensate, and the axial condensate in three-flavor chiral perturbation theory ($$\chi $$ χ PT) in the presence of an isospin chemical potential at next-to-leading order at zero temperature. It is shown that the three-flavor $$\chi $$ χ PT effective potential and condensates can be mapped onto two-flavor $$\chi $$ χ PT ones by integrating out mesons with strange-quark content (kaons and eta), with renormalized couplings. We compare the results for the light-quark and pion condensates at finite pseudoscalar source with ($$2+1$$ 2 + 1 )-flavor lattice QCD, and we also compare the axial condensate at zero pseudoscalar and axial sources with lattice QCD data. We find that the light-quark, pion, and axial condensates are in very good agreement with lattice data. There is an overall improvement by including NLO effects.

Variational mass perturbation theory for light-front bound-state equations

1998 ◽  
Vol 57 (4) ◽  
pp. 2460-2474 ◽  
Author(s):  
Koji Harada ◽  
Thomas Heinzl ◽  
Christian Stern
Keyword(s):  
Perturbation Theory ◽  
Bound State ◽  
Light Front ◽  
State Equations

scholarly journals TWIST-THREE DISTRIBUTION f⊥(x, k⊥) IN LIGHT-FRONT HAMILTONIAN APPROACH

2011 ◽  
Vol 26 (35) ◽  
pp. 2653-2662 ◽  
Author(s):  
A. MUKHERJEE ◽  
R. KORRAPATI
Keyword(s):  
Perturbation Theory ◽  
Inelastic Scattering ◽  
Deep Inelastic Scattering ◽  
The State ◽  
Light Front ◽  
Hamiltonian Approach ◽  
Gluon Interaction

We calculate the twist-three distribution f⊥(x, k⊥) contributing to Cahn effect in unpolarized semi-inclusive deep inelastic scattering. We use light-front Hamiltonian technique and take the state to be a dressed quark at one-loop in perturbation theory. The "genuine twist-three" contribution comes from the quark–gluon interaction part in the operator and is explicitly calculated. f⊥(x, k⊥) is compared with f1(x, k⊥).

scholarly journals Gluon cascades and amplitudes in light-front perturbation theory

2013 ◽  
Vol 869 (1) ◽  
pp. 1-30 ◽  
Author(s):  
C.A. Cruz-Santiago ◽  
A.M. Staśto
Keyword(s):  
Perturbation Theory ◽  
Light Front

scholarly journals UTILITY OF GALILEAN SYMMETRY IN LIGHT-FRONT PERTURBATION THEORY: A NONTRIVIAL EXAMPLE IN QCD

1998 ◽  
Vol 13 (26) ◽  
pp. 4591-4604 ◽  
Author(s):  
A. HARINDRANATH ◽  
RAJEN KUNDU
Keyword(s):  
Field Theory ◽  
Perturbation Theory ◽  
Complex Structure ◽  
Light Front ◽  
Tree Level ◽  
Two Dimensional ◽  
Coupling Constant ◽  
Two Component ◽  
Covariant Field ◽  
Galilean Symmetry

Investigations have revealed a very complex structure for the coefficient functions accompanying the divergences for individual time(x+)-ordered diagrams in light-front perturbation theory. No guidelines seem to be available to look for possible mistakes in the structure of these coefficient functions emerging at the end of a long and tedious calculation, in contrast to covariant field theory. Since, in light-front field theory, the transverse boost generator is a kinematical operator which acts just like the two-dimensional Galilean boost generator in nonrelativistic dynamics, it may provide some constraint on the resulting structures. In this work we investigate the utility of Galilean symmetry beyond tree level in the context of coupling constant renormalization in light-front QCD using the two-component formalism. We show that for each x+-ordered diagram separately, the underlying transverse boost symmetry fixes relative signs of terms in the coefficient functions accompanying the diverging logarithms. We also summarize the results leading to coupling constant renormalization for the most general kinematics.

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