On the ξ\xi-Distribution of Inclusively Produced Particles in e+e−e^+e^- Annihilation

We discuss the momentum distributions of inclusively produced particles in $e^+e^-$ annihilation. We show that the dependence of the position of the maxima of the $\xi=\ln(1/z)$ spectra on the mass of the produced particles follows naturally from the general definition of fragmentation functions when energy-momentum conservation is correctly incorporated

Possible Explanations for the NuTeV Weinberg Angle Measurement

The NuTeV collaboration has made an independent determination of the Weinberg angle by measuring charged and neutral-current cross sections from neutrino and antineutrino DIS on iron. Their value differs by 3 standard deviations from that obtained from measurements at the Z pole. We review this experiment and assess various possible explanations for this result, both within the Standard Model ("old physics") and outside the Standard Model ("new physics").Comment: QCD Down Under Workshop, CSSM, Adelaide, Australia, Mar 10-19, 2004; 6 pages, 3 figs; updated references on QCD effect

QCD evolution of the spin structure functions of the neutron and proton

Models of the long-distance behavior of QCD can be used to make predictions for the twist-two piece of the current correlation function appearing in deep-inelastic scattering. The connection between the model predictions, valid at a four-momentum transfer squared Q2 of the order of 1 (GeV/c)2, and the data, collected at much higher Q2, is provided by perturbative QCD. We present here the details of a method, previously used for spin-averaged lepton scattering, applied to the spin-dependent case. We then use the method to make predictions for the spin structure functions gprotonl and gneutronl.A. W. Schreiber, A. W. Thomas, and J. T. Londerga

Validity of Flavor Symmetry and Charge Symmetry for Parton Distributions

Recent experimental measurements of the Gottfried Sum Rule, and pp and pD Drell-Yan processes, suggest significant violation of flavor symmetry in the proton sea. This interpretation rests on the assumption of parton charge symmetry. Our model calculations suggest charge symmetry violation [CSV] for parton valence distributions of a few percent. Precision measurements of structure functions in muon and neutrino experiments allow us to set rather stringent experimental limits on CSV in certain kinematic regions. In another region, these experiments suggest substantial CSV effects. We suggest experiments which could test parton CSV.Comment: 8 pages, 4 figures, talk at Workshop on Future Directions in Quark-Nuclear Physics, Center for the Subatomic Structure of Matter, Adelaide, Australia, Mar 9-20, 1998, to appear in conference proceeding

Charge Symmetry Violation Corrections to Determination of the Weinberg Angle in Neutrino Reactions

We show that the correction to the Paschos-Wolfenstein relation associated with charge symmetry violation in the valence quark distributions is essentially model independent. It is proportional to a ratio of quark momenta that is independent of Q^2. This result provides a natural explanation of the surprisingly good agreement found between our earlier estimates within several different models. When applied to the recent NuTeV measurement, this effect significantly reduces the discrepancy with other determinations of the Weinberg angle.Comment: 7 pages, no figures; expanded discussion of N.ne.Z correction

Kaon-Nucleus Drell-Yan Processes and Kaon Structure Functions

We investigate the information which could be obtained from Drell-Yan processes with sufficiently intense beams of charged kaons on isoscalar targets. It is found that combinations of $K^+$ and $K^-$ Drell-Yan measurements on isoscalar nuclear targets would allow one to extract the kaon sea quark distributions. These cross sections are also sensitive to the strange valence quark distribution in the kaon, although one would need a significant increase over the presently available kaon fluxes in order to extract this quantity with sufficient accuracy.Comment: 9 pages plus 4 figures, on eps

A New Analysis of Charge Symmetry Violation in Parton Distributions

To date, the strongest indication of charge symmetry violation in parton distributions has been obtained by comparing the $F_2$ structure functions from CCFR neutrino data and NMC muon data. We show that in order to make precise tests of charge symmetry with the neutrino data, two conditions must be satisfied. First, the nuclear shadowing calculations must be made explicitly for neutrinos, not simply taken from muon data on nuclei. Second, the contribution of strange and charm quarks should be calculated explicitly using next-to-leading order [NLO] QCD, and the ``slow rescaling'' charm threshold correction should not be applied to the neutrino data. When these criteria are satisfied, the comparison is consistent with charge symmetry within the experimental errors and the present uncertainty in the strange quark distribution of the nucleon.Comment: 18 pages, 4 figure

Charge Symmetry Violating Contributions to Neutrino Reactions

The NuTeV group has measured charged and neutral current reactions for neutrinos on iron targets. Ratios of these cross sections provide an independent measurement of the Weinberg angle. The NuTeV value for sin^2 theta_W is three standard deviations larger than the value measured in other electroweak processes. By reviewing theoretical estimates of parton charge symmetry violation (CSV), we study CSV contributions to the NuTeV measurement. We conclude that charge symmetry violating effects should remove roughly 30% of the discrepancy between the NuTeV result and other determinations of sin^2 theta_W.Comment: 15 pages, 2 figures; Fig 2 replaced [CSV distribution calculated at low Q^2, evolved to 20 GeV^2]; table II change

The Asymptotic D- to S-State Ratio for 3-He

This work was supported by the National Science Foundation Grant NSF PHY 81-14339 and by Indiana Universit