Updates of the MMHT2014 PDFs

TL;DR

This paper updates the MMHT14 parton distribution functions by incorporating recent LHC data, resulting in reduced uncertainties in certain quark distributions and minor changes in central values, with a preliminary new fit called MMHT16.

Contribution

The paper introduces a preliminary updated PDF set, MMHT16, incorporating recent LHC data and analyzing its impact on parton distributions.

Findings

Reduced uncertainties in strange and valence quark PDFs.

Minimal changes in central PDF values with new data.

Extended - parametrization has minor effects.

Abstract

We briefly discuss some of the developments since the publication of the MMHT14 parton distributions. In particular we explore the impact of recent LHC data for $W^\pm,Z$ and $t\bar{t}$ production, and perform a preliminary new analysis including these data. In this re-fit (which we tentatively call `MMHT16') there are few changes of significance in the central values of the PDFs, but some data reduce the uncertainties, mainly in the strange and valence quark distributions. We find that an extended $\bar{d}-\bar{u}$ parametrization only leads to minor changes, with the difference going to zero as $x \to 0$. We comment on the determination of the photon PDF.