Perturbative and nonperturbative renormalization of anomalous quark triangles

Anomalous quark triangles with one axial and two vector currents are studied in special kinematics when one of the vector currents carries a soft momentum. According to the Adler-Bardeen theorem the anomalous longitudinal part of the triangle is not renormalized in the chiral limit. We derive a new nonrenormalization theorem for the transversal part of the triangle. This nonrenormalization, in difference with the longitudinal part, holds on only perturbatively. At the nonperturbative level we use the operator product expansion and the pion dominance in the longitudinal part to determine the magnetic susceptibility of the quark condensate, $\chi=-N_c/(4\pi^2 F_\pi^2)$.Comment: Revtex, 9 pages, 1 figure. A few references are added, discussion is extende

On the QCD corrections to Vainshtein's theorem for VVA correlator

We point out that, contrary to existing claims of the opposite, Vainshtein's theorem on the non-renormalization of the correlator of an axial and two vector currents, is only valid in the chiral limit. When quarks, that contribute to the correlator, are massive, the QCD corrections do not vanish and the transversal and longitudinal functions are renormalized differently. We compute those corrections and study their implications for QCD effects in electroweak corrections to the muon anomalous magnetic moment.Comment: 6 pages, 4 figure

Art and culture as the main focus European philanthropy model

The article deals with the analysis of modern experience of European philanthropic activities aimed at implementation of socio-cultural projects which provide for preservation and translation of unique ethnic and cultural heritage.В представленной статье анализируется современный опыт европейской благотворительной деятельности, направленной на реализацию социокультурных проектов, предусматривающих сохранение и трансляцию уникального этнокультурного наследия

Non-renormalization of the full <VVA> correlator at two-loop order

By explicit calculation of the two-loop QCD corrections we show that for singlet axial and vector currents the full off-shell correlation function in the limit of massless fermions is proportional to the one-loop result, when calculated in the MS-bar scheme. By the same finite renormalization which is needed to make the one-loop anomaly exact to all orders, we arrive at the conclusion that two-loop corrections are absent altogether, for the complete correlator not only its anomalous part. In accordance with the one-loop nature of the correlator, one possible amplitude, which seems to be missing by accident at the one-loop level, also does not show up at the two-loop level.Comment: 6 pages, 1 figur

Radiative corrections to the structure functions and sum rules in polarized DIS

The one-loop NLO radiative corrections to the observables in polarized DIS using assumption that a quark is an essential massive particle are considered. If compared with classical QCD formulae the obtained results are identical for the unpolarized and different for polarized sum rules, that can be explained as the influence of the finite quark mass effects on NLO QCD corrections. The explicit expression for one-loop NLO QCD contribution to the structure function g_2 is presented.Comment: 6 pages,1 figure. Talk given at the International Workshop "Symmetry And Spin" - PRAHA-SPIN'9

Explicit Results for the Anomalous Three Point Function and Non-Renormalization Theorems

Two-loop corrections for the correlator of the singlet axial and vector currents in QCD are calculated in the chiral limit for arbitrary momenta. Explicit calculations confirm the non-renormalization theorems derived recently by Vainshtein and Knecht et.al. We find that as in the one-loop case also at the two loops the correlator has only 3 independent form-factors instead of 4. From the explicit results we observe that the two-loop correction to the correlator is equal to the one-loop result times the constant factor C_2(R) alpha_s/pi in the MSbar scheme. This holds for the full correlator, for the anomalous longitudinal as well as for the non- anomalous thansversal amplitudes. The finite overall alpha_s dependent constant has to be normalized away by renormalizing the axial current according to Witten's algebraic/geometrical constraint on the anomalous Ward identity. Our observations, together with known facts, suggest that in perturbation theory the correlator is proportional to the one-loop term to all orders and that the non- renormalization theorem of the Adler-Bell-Jackiw anomaly carries over to the full correlator.Comment: 10 pages, 2 Postscript figures, uses axodraw.st

Radiative corrections to deep-inelastic ed−ed- scattering. Case of tensor polarized deuteron

The model-independent radiative corrections to deep-inelastic scattering of unpolarized electron beam off the tensor polarized deuteron target have been considered. The contribution to the radiative corrections due to the hard-photon emission from the elastic electron-deuteron scattering (the so-called elastic radiative tail) is also investigated. The calculation is based on the covariant parametrization of the deuteron quadrupole polarization tensor. The numerical estimates of the radiative corrections to the polarization observables have been done for the kinematical conditions of the current experiment at HERAComment: 21 pages, 5 figure

Radiative Correction to the Transferred Polarization in Elastic Electron-Proton Scattering

Model independent radiative correction to the recoil proton polarization for the elastic electron-proton scattering is calculated within method of electron structure functions. The explicit expressions for the recoil proton polarization are represented as a contraction of the electron structure and the hard part of the polarization dependent contribution into cross-section. The calculation of the hard part with first order radiative correction is performed. The obtained representation includes the leading radiative corrections in all orders of perturbation theory and the main part of the second order next-to-leading ones. Numerical calculations illustrate our analytical results.Comment: 14 pages, 4 figure

Tagged-photon events in polarized DIS process

Deep-inelastic events for the scattering of the longitudinally polarized electron by polarized proton with tagged collinear photon radiated from initial-state electron are considered. The corresponding cross-section is derived in the Born approximation. The model-independent radiative corrections to the Born cross-section are also calculated. Obtained result is applied to the case of elastic scattering.Comment: 14 pages, 2 figures, submitted to JET

Two--Loop Electroweak Corrections to the Muon g-2: a new class of Hadronic Contributions

We discuss, within the framework of the Standard Model, the calculation of the two-loop electroweak contributions to the anomalous magnetic moment of the muon involving triangle fermionic loops of leptons and quarks. Because of the large ratios of masses involved, these contributions are rather large. The result we obtain differs from a previous estimate reported in the literature. The discrepancy originates in the cancellation of anomalies in $SU(3)_c\times SU(2)_L\times U(1)_Y$, a cancellation that requires the consideration of both leptons {\it and} quarks within each generation and that had been previously overlooked.Comment: 9 pages, 5 figs., sign error corrected, numerical result changes slightly, note added referring to some recent related wor