NNLO QCD contributions to the flavor non-singlet sector of F2(x,Q2){\bf {F_2(x,Q^2)}}

We present the results of our QCD analysis for nonsinglet unpolarized quark distributions and structure function $F_2(x,Q^2)$. New parameterizations are derived for the nonsinglet quark distributions for the kinematic wide range of $x$ and $Q^2$. The analysis is based on the Jacobi polynomials expansion of the structure function. The higher twist contributions of proton and deuteron structure function are obtained in the large $x$ region. Our calculations for nonsinglet unpolarized quark distribution functions based on the Jacobi polynomials method are in good agreement with the other theoretical models. The values of $\Lambda_{QCD}$ and $\alpha_s(M_z^2)$ are determined.Comment: 29 pages, 8 figure

Fixation of theoretical ambiguities in the improved fits to xF3xF_3 CCFR data at the next-to-next-to-leading order and beyond

Using the results for the NNLO QCD corrections to anomalous dimensions of odd $xF_3$ Mellin moments and N$^3$LO corrections to their coefficient functions we improve our previous analysis of the CCFR'97 data for $xF_3$. The possibility of extracting from the fits of $1/Q^2$-corrections is analysed using three independent models,including infrared renormalon one. Theoretical quetion of applicability of the renormalon-type inspired large-$\beta_0$ approximation for estimating corrections to the coefficient functions of odd $xF_3$ and even non-singlet $F_2$ moments are considered. The comparison with [1/1] Pad\'e estimates is given. The obtained NLO and NNLO values of $\alpha_s(M_Z)$ are supporting the results of our less definite previous analysis and are in agreement with the world average value $\alpha_s(M_Z)\approx 0.118$. We also present first N$^3$LO extraction of $\alpha_s(M_Z)$. The interplay between higher-order perturbative QCD corrections and $1/Q^2$-terms is demonstrated. The results of our studies are compared with those obtained recently using the NNLO model of the kernel of DGLAP equation and with the results of the NNLO fits to CCFR'97 $xF_3$ data, performed by the Bernstein polynomial technique.Comment: The errors in the coefficients $C_{F_3}^{(3)}(n)$ of ($\alpha_s/4\pi)^3 QCD corrections to the Mellin moments of xF_3 structure function were detected. The application of the corrected results in the fits resulted in decrease of N$^3$LO values of$\Lambda_{\bar{MS}}^{(4)}$ in Tables 6,11,12 by 3 MeV only (details are in the enclosed Erratum (in press)

Application of new multiloop QCD input to the analysis of xF3xF_3 data

The new theoretical input to the analysis of the experimental data of the CCFR collaboration for $F_3$ structure function of $\nu N$ deep inelastic scattering is considered. This input comes from the next-to-next-to-leading order corrections to the anomalous dimensions of the Mellin moments of the $F_3$ structure function. The QCD scale $\Lambda_{\overline{MS}}^{(4)}$ is extracted from higher-twist independent fits. The results obtained demonstrate the minimization of the influence of perturbative QCD contributions to the value of $\Lambda_{\overline{MS}}^{(4)}$Comment: 7 pages, Based on contributions to Proceedings of Quarks-2000 Int. Seminar, Pushkin, May 2000, Russia and ACAT'2000 Workshop, Fermilab, October 2000, USA; definite shortcomings are eliminated, resulys unchange

Next-to-next-to-leading order fits to CCFR'97 xF3xF_3 data and infrared renormalons

We briefly summarize the outcomes of our recent improved fits to the experimental data of CCFR collaboration for $xF_3$ structure function of $\nu N$ deep-inelastic scattering at the next-to-next-to-leading order. Special attention is paid to the extraction of $\alpha_s(M_Z)$ and the parameter of the infrared renormalon model for $1/Q^2$-correction at different orders of perturbation theory. The results can be of interest for planning similar studies using possible future data of Neutrino Factories.Comment: 3 pages, presented at WG3 of 4th NuFact'02 Workshop, London 1-6 July, 200

Electron Spin Dynamics of the Superconductor CaC6 probed by ESR

Conduction Electron Spin Resonance (CESR) was measured on a thick slab of CaC6 in the normal and superconducting state. A surprising increase of the CESR intensity below Tc can not be explained by the theoretically predicted change in spin susceptibility. It is interpreted as a vortex enhanced increase of the effective skin depth. Non-linear microwave absorption measurements in the superconducting state describe CaC6 as an anisotropic BCS superconductor. The study of the spin dynamics in the superconducting state and the discovery of the vortex enhanced increase of the skin depth poses a challenge to theory to provide a comprehensive description of the observed phenomena. CESR data in the normal state characterize CaC6 as a three-dimensional (3D) metal. The analysis suggests that the scattering of conduction electrons is dominated by impurities and supports the description of superconductivity in the dirty limit.Comment: 4 pages, 3 figure