Deviation pattern approach for optimizing perturbative terms of QCD renormalization group invariant observables

We first consider the idea of renormalization group-induced estimates, in the context of optimization procedures, for the Brodsky-Lepage-Mackenzie approach to generate higher-order contributions to QCD perturbative series. Secondly, we develop the deviation pattern approach (DPA) in which through a series of comparisons between lower-order RG-induced estimates and the corresponding analytical calculations, one could modify higher-order RG-induced estimates. Finally, using the normal estimation procedure and DPA, we get estimates of $\alpha_s^4$ corrections for the Bjorken sum rule of polarized deep-inelastic scattering and for the non-singlet contribution to the Adler function.Comment: 5 pages, proceedings for the XXIII International Baldin Seminar on High Energy Physics Problems "Relativistic Nuclear Physics and Quantum Chromodynamics

Nucleon structure functions in noncommutative space-time

In the context of noncommutative space-time, we investigate the nucleon structure functions which plays an important role to identify the internal structure of nucleons. We use the corrected vertices and employ new vertices that appear in two approaches of noncommutativity and calculate the proton structure functions in terms of noncommutative tensor \theta_{\mu\nu}. To check our result, we plot the nucleon structure function (NSF), F_2(x), and compare it with experimental data and the result coming out from the GRV, GJR and CT10 parametrization models. We show that new vertex which is arising the noncommutativity correction will lead us to better consistency between theoretical result and experimental data for NSF. This consistency would be better at small values of x-Bjorken variable. To indicate and confirm the validity of our calculations, we also act conversely and obtain an lower bound for the numerical values of \Lambda_{NC} scale which are corresponding to the recent reports.Comment: 28 pages, 5 figure