Unbiased analysis of CLEO data at NLO and pion distribution amplitude

We discuss different QCD approaches to calculate the form factor F^{\gamma^*\gamma\pi}(Q^2) of the \gamma^*\gamma\to\pi^{0} transition giving preference to the light-cone QCD sum rules (LCSR) approach as being the most adequate. In this context we revise the previous analysis of the CLEO experimental data on F^{\gamma^*\gamma\pi}(Q^{2}) by Schmedding and Yakovlev. Special attention is paid to the sensitivity of the results to the (strong radiative) \alpha_s-corrections and to the value of the twist-four coupling \delta^2. We present a full analysis of the CLEO data at the NLO level of LCSRs, focusing particular attention to the extraction of the relevant parameters to determine the pion distribution amplitude, i.e., the Gegenbauer coefficients a_2 and a_4. Our analysis confirms our previous results and also the main findings of Schmedding and Yakovlev: both the asymptotic, as well as the Chernyak--Zhitnitsky pion distribution amplitudes are completely excluded by the CLEO data. A novelty of our approach is to use the CLEO data as a means of determining the value of the QCD vacuum non-locality parameter \lambda^2_q = / =0.4 GeV^2, which specifies the average virtuality of the vacuum quarks.Comment: 25 pages, 5 figures, 4 tables; format and margins corrected to fit page size; small changes in the text and correction of misprint

Mathematical Methods and Algorithms of Mobile Parallel Computing on the Base of Multi-core Processors

This article deals with mathematical models and algorithms, providing mobility of sequential programs parallel representation on the high-level language, presents formal model of operation environment processes management, based on the proposed model of programs parallel representation, presenting computation process on the base of multi-core processors