scholarly journals Decoupling of zero modes and covariance in the light-front formulation of supersymmetric theories

1998 ◽  
Vol 58 (12) ◽  
Author(s):  
M. Burkardt ◽  
F. Antonuccio ◽  
S. Tsujimaru
Keyword(s):  
Light Front ◽  
Zero Modes ◽  
Supersymmetric Theories

scholarly journals Index theorem for non-supersymmetric fermions coupled to a non-Abelian string and electric charge quantization

2018 ◽  
Vol 33 (09) ◽  
pp. 1850053
Author(s):  
M. Shifman ◽  
A. Yung
Keyword(s):  
Gauge Group ◽  
Electric Charge ◽  
Index Theorem ◽  
Index Theorems ◽  
Zero Modes ◽  
Left Handed ◽  
Charge Quantization ◽  
Supersymmetric Theories ◽  
String Background

Non-Abelian strings are considered in non-supersymmetric theories with fermions in various appropriate representations of the gauge group U[Formula: see text]. We derive the electric charge quantization conditions and the index theorems counting fermion zero modes in the string background both for the left-handed and right-handed fermions. In both cases we observe a non-trivial [Formula: see text] dependence.

scholarly journals Zero modes in the light-front coupled-cluster method

2014 ◽  
Vol 340 (1) ◽  
pp. 188-204 ◽  
Author(s):  
Sophia S. Chabysheva ◽  
John R. Hiller
Keyword(s):  
Light Front ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Coupled Cluster Method ◽  
Zero Modes

Construction of the light-front QCD Hamiltonian with zero modes modeling the vacuum

2011 ◽  
Vol 169 (2) ◽  
pp. 1600-1610 ◽  
Author(s):  
M. Yu. Malyshev ◽  
E. V. Prokhvatilov
Keyword(s):  
Light Front ◽  
Zero Modes

scholarly journals QUANTUM GAUGE BOSON PROPAGATORS IN THE LIGHT FRONT

2004 ◽  
Vol 19 (38) ◽  
pp. 2831-2844 ◽  
Author(s):  
A. T. SUZUKI ◽  
J. H. O. SALES
Keyword(s):  
Gauge Boson ◽  
Degrees Of Freedom ◽  
Zero Mode ◽  
Light Front ◽  
Gauge Fields ◽  
Algebraic Condition ◽  
Constant Vector ◽  
Gauge Bosons ◽  
Zero Modes ◽  
Boson Propagator

Gauge fields in the light front are traditionally addressed via the employment of an algebraic condition n·A=0 in the Lagrangian density, where Aμ is the gauge field (Abelian or non-Abelian) and nμ is the external, light-like, constant vector which defines the gauge proper. However, this condition though necessary is not sufficient to fix the gauge completely; there still remains a residual gauge freedom that must be addressed appropriately. To do this, we need to define the condition (n·A)(∂·A)=0 with n·A=0=∂·A. The implementation of this condition in the theory gives rise to a gauge boson propagator (in momentum space) leading to conspicuous nonlocal singularities of the type (k·n)-α where α=1,2. These singularities must be conveniently treated, and by convenient we mean not only mathemathically well-defined but physically sound and meaningful as well. In calculating such a propagator for one and two noncovariant gauge bosons those singularities demand from the outset the use of a prescription such as the Mandelstam–Leibbrandt (ML) one. We show that the implementation of the ML prescription does not remove certain pathologies associated with zero modes. However we present a causal, singularity-softening prescription and show how to keep causality from being broken without the zero mode nuisance and letting only the propagation of physical degrees of freedom.

scholarly journals Light-front projection of spin-1 electromagnetic current and zero-modes

2012 ◽  
Vol 708 (1-2) ◽  
pp. 87-92 ◽  
Author(s):  
J.P.B.C. de Melo ◽  
T. Frederico
Keyword(s):  
Light Front ◽  
Electromagnetic Current ◽  
Zero Modes

scholarly journals Current-Component Independent Transition Form Factors for Semileptonic and Rare D ⟶ π K Decays in the Light-Front Quark Model

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Ho-Meoyng Choi
Keyword(s):  
Form Factor ◽  
Quark Model ◽  
Form Factors ◽  
Light Front ◽  
Recent Analysis ◽  
Identical Result ◽  
Current Component ◽  
Tensor Form ◽  
Zero Modes ◽  
Valence Region

We investigate the exclusive semileptonic and rare D ⟶ π K decays within the standard model together with the light-front quark model (LFQM) constrained by the variational principle for the QCD-motivated effective Hamiltonian. The form factors are obtained in the q + = 0 frame and then analytically continue to the physical timelike region. Together with our recent analysis of the current-component independent form factors f ± q 2 for the semileptonic decays, we present the current-component independent tensor form factor f T q 2 for the rare decays to make the complete set of hadronic matrix elements regulating the semileptonic and rare D ⟶ π K decays in our LFQM. The tensor form factor f T q 2 are obtained from two independent sets J T + ⊥ , J T + − of the tensor current J T u v . As in our recent analysis of f − q 2 , we show that f T q 2 obtained from the two different sets of the current components gives the identical result in the valence region of the q + = 0 frame without involving the explicit zero modes and the instantaneous contributions. The implications of the zero modes and the instantaneous contributions are also discussed in comparison between the manifestly covariant model and the standard LFQM. In our numerical calculations, we obtain the q 2 -dependent form factors ( f ± , f T ) for D ⟶ π K and branching ratios for the semileptonic D ⟶ π K ℓ v ℓ ℓ = e , μ decays. Our results show in good agreement with the available experimental data as well as other theoretical model predictions.

scholarly journals Nonvanishing zero modes in the light-front current

1998 ◽  
Vol 58 (7) ◽  
Author(s):  
Ho-Meoyng Choi ◽  
Chueng-Ryong Ji
Keyword(s):  
Light Front ◽  
Zero Modes

Light front field theory: An advanced Primer

2007 ◽  
Vol 57 (3) ◽  
Author(s):  
L'ubomír Martinovič
Keyword(s):  
Field Theory ◽  
Detailed Comparison ◽  
Light Front ◽  
Two Dimensional ◽  
Schwinger Model ◽  
Initial Space ◽  
Model Hamiltonian ◽  
Spatial Volume ◽  
Hamiltonian Perturbation Theory ◽  
Light Front Quantization

Light front field theory: An advanced PrimerWe present an elementary introduction to quantum field theory formulated in terms of Dirac's light front variables. In addition to general principles and methods, a few more specific topics and approaches based on the author's work will be discussed. Most of the discussion deals with massive two-dimensional models formulated in a finite spatial volume starting with a detailed comparison between quantization of massive free fields in the usual field theory and the light front (LF) quantization. We discuss basic properties such as relativistic invariance and causality. After the LF treatment of the soluble Federbush model, a LF approach to spontaneous symmetry breaking is explained and a simple gauge theory - the massive Schwinger model in various gauges is studied. A LF version of bosonization and the massive Thirring model are also discussed. A special chapter is devoted to the method of discretized light cone quantization and its application to calculations of the properties of quantum solitons. The problem of LF zero modes is illustrated with the example of the two-dimensional Yukawa model. Hamiltonian perturbation theory in the LF formulation is derived and applied to a few simple processes to demonstrate its advantages. As a byproduct, it is shown that the LF theory cannot be obtained as a "light-like" limit of the usual field theory quantized on an initial space-like surface. A simple LF formulation of the Higgs mechanism is then given. Since our intention was to provide a treatment of the light front quantization accessible to postgradual students, an effort was made to discuss most of the topics pedagogically and a number of technical details and derivations are contained in the appendices.

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