English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We analyze effects due to transverse degrees of freedom in QCD calculationsof the fundamental hard exclusive amplitude of $\gamma^*\gamma \to \pi^0$transition. A detailed discussion is given of the relation between the modifiedfactorization approach (MFA) of Sterman et al. and standard factorization(SFA). Working in Feynman gauge, we construct basic building blocks of MFA fromthe one-loop coefficient function of the SFA, demonstrating that Sudakoveffects are distinctly different from higher-twist corrections. We show alsothat the handbag-type diagram, contrary to naive expectations, does not containan infinite chain of $(M^2/Q^2)^n$ corrections: they come only from diagramswith transverse gluons emitted from the hard propagator. A simpler pictureemerges within the QCD sum rule approach: the sum over soft $\bar q G ... G q$Fock components is dual to $\bar qq$ states generated by the local axialcurrent. We combine the results based on QCD sum rules with pQCD radiativecorrections and observe that the gap between our curves for the asymptotic andCZ distribution amplitudes is sufficiently large for an experimentaldiscrimination between them.Comment: LaTeX, 34 pages, 4 figures; minor change

physical review. d. particles, fields, gravitation, and cosmology/physical review. d. particles and fields

Transverse momentum and Sudakov effects in exclusive QCD processes:<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi>γ</mml:mi></mml:mrow><mml:mrow><mml:mi>*</mml:mi></mml:mrow></mml:msup></mml:mrow><mml:mi>γ</mml:mi><mml:mrow><mml:msup><mml:mrow><mml:mi>π</mml:mi></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math>form factor

Transverse momentum and Sudakov effects in exclusive QCD processes:γ*γπ0form factor