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 Tools annual

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 monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

We study the heavy-quark contributions to the proton structure functions$F_2^i(x,Q^2)$ and $F_L^i(x,Q^2)$, with $i=c,b$, for small values of Bjorken's$x$ variable and provide compact formulas for their ratios $R_i=F_L^i/F_2^i$that are useful to extract $F_2^i(x,Q^2)$ from measurements of the doublydifferential cross section of inclusive deep-inelastic scattering at DESY HERA.Our approach naturally explains why $R_i$ is approximately independent of $x$and the details of the parton distribution functions in the low-$x$ regime.

Heavy-quark contributions to the ratio FL/F2 at low values of the Bjorken variable x