Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Light front Bethe-Salpeter equation applied to form factors, generalized
  parton distributions and generalized distribution amplitudes   We present an intuitive, light front reduction scheme for the Bethe-Salpeter
equation that consists of iterations of the (light front) energy dependent
covariant equation followed by an instantaneous approximation. This scheme is
equivalent to and motivates the form of a standard reduction that reproduces
light front, time ordered perturbation theory for bound states. We use this
three-dimensional light front formalism to compute electromagnetic form factors
between bound states to show how higher, light front Fock components arise from
the covariant Bethe-Salpeter wave function. Moreover, we show that non-wave
function vertices, which arise after integration over the minus momenta, are
completely removed in favor of higher Fock states when one correctly takes into
account all contributions at a given order in perturbation theory. Such
non-wave function vertices are shown only to occur in models in which the
interactions are instantaneous. These models lack true higher Fock states. The
normalization of the reduced wave function is derived from the covariant
framework and related to nonvalence probabilities using familiar Fock space
projection operators. Using a simple model, we obtain expressions for
generalized parton distributions that are continuous. The nonvanishing of these
distributions at the crossover between kinematic regimes (where the plus
component of the struck quark's momentum is equal to the plus component of the
momentum transfer) is tied to higher Fock components. Lastly we apply the light
front reduction to timelike form factors and derive expressions for the
generalized distribution amplitudes in this model.

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The categories of this paper are: cs
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The categories of this paper are: funct-an
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The categories of this paper are: comp-gas
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The categories of this paper are: alg-geom
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The categories of this paper are: acc-phys
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The categories of this paper are: eess
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: bayes-an
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The categories of this paper are: q-alg
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The categories of this paper are: math
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The categories of this paper are: cond-mat
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The categories of this paper are: physics
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The categories of this paper are: cmp-lg
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The categories of this paper are: plasm-ph
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The categories of this paper are: nucl-ex