arXiv subjects

Felix M. Lev

Publications and source records attributed to Felix M. Lev.

27 records · Page 2Linked to original sources

arXiv1996

Role of Nonperturbative Effects in Deep Inelastic Scattering Revisited

Restrictions imposed on the (electromagnetic or weak) current operator by its commutation relations with the representation operators of the Poincare group are considered in detail. We argue that the present theory of deep inelastic scattering based on perturbative QCD does not take into account the dependence of the current operator on the nonperturbative part of the quark-gluon interaction which cannot be neglected even in leading order in $1/Q$, where $Q$ is the magnitude of the momentum transfer.

hep-ph↗

arXiv1996

Problems with Nonperturbative Effects in Deep Inelastic Scattering

We consider restrictions imposed on the (electromagnetic or weak) current operator by its commutation relations with the representation operators of the Poincare group and show that the nonperturbative part of the current operator contributes to deep inelastic scattering even in leading order in $1/Q$ where $Q$ is the magnitude of the momentum transfer. Some consequences of this result are discussed.

hep-ph↗

arXiv1996

Do Sum Rules in Deep Inelastic Scattering Follow From QCD?

We consider restrictions imposed on the electromagnetic and weak current operators by Poincare invariance and show that some assumptions used in deriving the sum rules in deep inelastic scattering (DIS) have no physical ground. In particular there is no ground to neglect the contribution of nonperturbative effects to these operators, even in the Bjorken limit. Therefore the conclusion that the sum rules in DIS unambiguously follow from QCD is not substantiated.

hep-ph↗

arXiv1995

Current Operators in Quantum Field Theory and Sum Rules in Deep Inelastic Scattering

It is shown that in the general case the canonical construction of the current operators in quantum field theory does not render a bona fide vector field since Lorentz invariance is violated by Schwinger terms. We argue that the nonexistence of the canonical current operators for spinor fields follows from a very simple algebraic consideration. As a result, the well-known sum rules in deep inelastic scattering are not substantiated.

hep-th↗

arXiv1995

Some Aspects of Nuclear Deep Inelastic Scattering

Nuclear deep inelastic scattering is considered in the framework of a model in which the current operator explicitly satisfies Poincare invariance and current conservation. The results considerably differ from the standard ones at small values of the Bjorken variable $x$. In particular, it is impossible to extract the neutron structure functions from the deuteron data at x<0.01 and we predict that the behavior of the deuteron structure functions at low x and large momentum transfer considerably differs from the behavior of the nucleon structure functions at such conditions. We also argue that for heavier nuclei the effect of the final state interaction is important even in the Bjorken limit.

hep-ph↗

arXiv1995

The Problem of Constructing the Current Operators in Quantum Field Theory

Lorentz invariance of the current operators implies that they satisfy the well-known commutation relations with the representation operators of the Lorentz group. It is shown that if the standard construction of the current operators in quantum field theory is used then the commutation relations are broken by the Schwinger terms.

hep-th↗

arXiv1995

Forms of Relativistic Dynamics, Current Operators and Deep Inelastic Lepton-Nucleon Scattering

The three well-known forms of relativistic dynamics are unitarily equivalent and the problem of constructing the current operators can be solved in any form. However the notion of the impulse approximation is reasonable only in the point form. In particular, the parton model which is the consequence of the impulse approximation in the front form is incompatible with Lorentz invariance, P invariance and T invariance. The results for deep inelastic scattering based on the impulse approximation in the point form give natural qualitative explanation of the fact that the values given by the parton model sum rules exceed the corresponding experimental quantities.

hep-ph↗

arXiv1995

Qualitative Consideration Of The Effect Of Binding In Deep Inelastic Scattering

In our recent paper (hep-ph/9501348) we argued that the Bjorken variable $x$ in deep inelastic scattering cannot be interpreted as the light cone momentum fraction $ξ$ even in the Bjorken limit and in zero order of the perturbation theory. The purpose of the present paper is to qualitatively explain this fact using only a few simplest kinematical relations.

hep-ph↗

arXiv1994

Exact Construction of the Electromagnetic Current Operator for Relativistic Composite Systems

The electromagnetic current operator of a composite system must be a relativistic vector operator satisfying current conservation, cluster separability and the condition that interactions between the constituents do not renormalize the total electric charge. Assuming that these interactions are described in the framework of relativistic quantum mechanics of systems with a fixed number of particles we explicitly construct the current operators satisfying the above properties in cases of two and three particles and prove that solutions exist for any number of particles. The consideration is essentially based on the method of packing operators in the point form of relativistic dynamics developed by Sokolov. Using the method developed by Sokolov and Shatny we also construct the current operators in the instant and front forms and prove that the corresponding results are physically equivalent. The paper is self-contained what makes it possible for the reader to learn both, relativistic quantum mechanics of systems with a fixed number of particles and the problem of constructing the electromagnetic current operator for such systems.

hep-ph↗