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 show that respecting the underlying Lorentz structure in the parton modelhas very strong consequences. Failure to insist on the correct Lorentzcovariance is responsible for the existence of contradictory results in theliterature for the polarized structure function g_2(x), whereas with thecorrect imposition we are able to derive the Wandzura-Wilczek relation forg_2(x) and the target-mass corrections for polarized deep inelastic scatteringwithout recourse to the operator product expansion. We comment briefly on theproblem of threshold behaviour in the presence of target-mass corrections.Careful attention to the Lorentz structure has also profound implications forthe structure of the transverse momentum dependent parton densities often usedin parton model treatments of hadron production, allowing the k_T dependence tobe derived explicitly. It also leads to stronger positivity and Soffer-typebounds than usually utilized for the collinear densities.

On the importance of Lorentz structure in the parton model: target mass corrections, transverse momentum dependence, positivity bounds