Strange and non-strange distributions from the collider data

Understand

We check the stability of the ABMP16 fit with respect to modifications of quark PDFs suggested in the recent literature: the strange sea enhancement and a positive non-vanishing $d/u$ ratio at $x \to 1$.

• These possibilities are examined using test versions of the ABMP16 PDF fit which demonstrate no need of those changes.
• Furthermore, we localize peculiar features in other analyses which are responsible for a different behaviour of the PDFs obtained.
• The strange sea enhancement can be explained by a choice of the PDF shapes being not flexible enough and therefore leading to an over-suppressed $d$-quark distribution.