Relations Between NC and CC Neutrino Structure Functions for Nucleons and Nuclei
The relations between neutrino NC and CC structure functions and cross sections, which are driven by isospin symmetry, are discussed for nucleons and nuclei.
hep-ph↗
arXiv subjects
S. A. Kulagin
Publications and source records attributed to S. A. Kulagin.
On the Paschos-Wolfenstein Relationship for Nuclei
Nuclear effects and QCD perturbative corrections to the Paschos-Wolfenstein relationship are discussed. We argue that perturbative corrections largely cancel out in this relationship for total cross sections while the neutron excess correction in heavy nuclei is enhanced by Fermi motion and nuclear binding effects. These observations are discussed in the context of NuTeV measurement of the Weinberg mixing angle.
hep-ph↗
Isospin Dependence of Power Corrections in Deep Inelastic Scattering
We present results of a perturbative QCD analysis of deep inelastic measurements of both the deuteron and proton structure functions. We evaluate the theoretical uncertainty associated to nuclear effects in the deuteron, and we extract simultaneously the isospin depedendence of: i)the higher twists terms; ii) the ratio of the longitudinal to transverse cross sections; iii) the ratio of the neutron to proton structure functions. The extraction of the latter, in particular, has been at the center of an intense debate. Its accurate determination is crucial both theoretically and for the interpretation of the more precise neutrino experiments including the newly planned high intensity 50 GeV proton synchrotron.
hep-ph↗
Paschos-Wolfenstein Relationship for Nuclei and the NuTeV sin^2(theta_W) Measurement
We discuss nuclear effects in the Paschos-Wolfenstein relationship in the context of extraction of the weak mixing angle. We point out that the neutron excess correction to the Paschos-Wolfenstein relationship for a neutron-rich target is negative and large on the scale of experimental errors of a recent NuTeV measurement. We found a larger neutron excess correction to the Paschos-Wolfenstein relationship for total cross sections than that discussed by the NuTeV collaboration. Phenomenological applications of this observation are discussed in the context of the NuTeV deviation. Uncertainties in the neutron excess correction are estimated. Effects due to Fermi motion, nuclear binding, and nuclear shadowing are also discussed in the context of total cross sections.
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Higher Twists and Nuclear Effects
We discuss the impact of nuclear effects on the higher twist terms using a particular example of the structure function xF_3 as extracted from a QCD fit to neutrino deep inelastic data on a heavy nucleus target.
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Physics at the front-end of a neutrino factory: a quantitative appraisal
We present a quantitative appraisal of the physics potential for neutrino experiments at the front-end of a muon storage ring. We estimate the forseeable accuracy in the determination of several interesting observables, and explore the consequences of these measurements. We discuss the extraction of individual quark and antiquark densities from polarized and unpolarized deep-inelastic scattering. In particular we study the implications for the undertanding of the nucleon spin structure. We assess the determination of alpha_s from scaling violation of structure functions, and from sum rules, and the determination of sin^2(theta_W) from elastic nu-e and deep-inelastic nu-p scattering. We then consider the production of charmed hadrons, and the measurement of their absolute branching ratios. We study the polarization of Lambda baryons produced in the current and target fragmentation regions. Finally, we discuss the sensitivity to physics beyond the Standard Model.
hep-ph↗
Nuclear effects and higher twists in F3 structure function
We analyze the CCFR collaboration iron target data on the xF3 structure function making particular emphasis on the extraction of the higher twist contributions from data. Corrections for nuclear effects are applied in order to extract data on the structure function of the isoscalar nucleon. Our analysis confirms the observation made earlier, that the higher twist terms depend strongly on the level to which QCD perturbation theory analysis is applied. We discuss the impact of nuclear effects on the higher twist term as well as on the QCD scale parameter Lambda_{\bar{MS}} extracted from the fit to data.
hep-ph↗
Nuclear Shadowing in Neutrino Deep Inelastic Scattering
We discuss effect of nuclear shadowing in neutrino deep-inelastic scattering in terms of non perturbative parton model. We found that for small Bjorken $x$ and large $Q^2$ the structure function $F_3$ is shadowed in nuclei about two times as stronger as $F_2$. The underlying reason and phenomenological aspects of this observation are discussed.
hep-ph↗
Nuclear Effects in the F_3 Structure Function
We discuss nuclear effects in the structure function F_3 measured in neutrino deep-inelastic scattering on heavy nuclear targets.
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Nuclear Effects In The F_3 Structure Function For Finite And Asymptotic Q^2
We study nuclear effects in the structure function F_3 which describes the parity violating part of the charged-current neuitrino nucleon deep inelastic scattering. Starting from a covariant approach we derive a factorized expression for the nuclear structure function in terms of nuclear spectral function and off-shell nucleon structure functions valid for arbitrary momentum transfer Q and in the limit of weak nuclear binding, i.e. when a nucleus can be treated as a non-relativistic system. We develop a systematic expansion of nuclear structure functions in terms of Q^{-2} series caused by nuclear effects ("nuclear twist" series). Basing on this expansion we calculate nuclear corrections to the Gross-Llewellyn-Smith sum rule as well as to higher moments of F_3. We show that corrections to the GLS sum rule due to nuclear effects cancel out in the Bjorken limit and calculate the corresponding Q^{-2} correction. Special attention is payed to the discussion of the off-shell effects in the structure functions. A sizable impact of these effects both on Q^2- and x-dependence of nuclear structure functions is found.
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Nucleon Structure Functions at Moderate Q**2: Relativistic Constituent Quarks and Spectator Mass Spectrum
We present a model description of the nucleon valence structure function applicable over the entire region of the Bjorken variable x, and above moderate values of Q**2 (> 1 GeV**2). We stress the importance of describing the complete spectrum of intermediate states which are spectator to the deep-inelastic collision. At a scale of 1 GeV**2 the relevant degrees of freedom are constituent quarks and pions. The large-x region is then described in terms of scattering from constituent quarks in the nucleon, while the dressing of constituent quarks by pions plays an important role at intermediate x values. The correct small-x behavior, which is necessary for the proper normalization of the valence distributions, is guaranteed by modeling the asymptotic spectator mass spectrum according to Regge phenomenology.
nucl-th↗
SPIN-DEPENDENT NUCLEAR STRUCTURE FUNCTIONS: GENERAL APPROACH WITH APPLICATION TO THE DEUTERON
We study deep-inelastic scattering from polarized nuclei within a covariant framework. A clear connection is established between relativistic and non-relativistic limits, which enables a rigorous derivation of convolution formulae for the spin-dependent nuclear structure functions g_1^A and g_2^A in terms of off-mass-shell extrapolations of polarized nucleon structure functions, g_1^N and g_2^N. Approximate expressions for g_{1,2}^A are obtained by expanding the off-shell g_{1,2}^N about their on-shell limits. As an application of the formalism we consider nuclear effects in the deuteron, knowledge of which is necessary to obtain accurate information on the spin-dependent structure functions of the neutron.
hep-ph↗
Shadowing, Binding and Off-Shell Effects in Nuclear Deep Inelastic Scattering
We present a unified description of nuclear deep inelastic scattering (DIS) over the whole region $0<x<1$ of the Bjorken variable. Our approach is based on a relativistically covariant formalism which uses analytical properties of quark correlators. In the laboratory frame it naturally incorporates two mechanisms of DIS: (I) scattering from quarks and antiquarks in the target and (II) production of quark-antiquark pairs followed by interactions with the target. We first calculate structure functions of the free nucleon and develop a model for the quark spectral functions. We show that mechanism (II) is responsible for the sea quark content of the nucleon while mechanism (I) governs the valence part of the nucleon structure functions. We find that the coherent interaction of $\bar qq$ pairs with nucleons in the nucleus leads to shadowing at small $x$ and discuss this effect in detail. In the large $x$ region DIS takes place mainly on a single nucleon. There we focus on the derivation of the convolution model. We point out that the off-shell properties of the bound nucleon structure function give rise to sizable nuclear effects.
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