Speaker
Description
We present a new global determination of the helicity-dependent parton distribution functions (PDFs) of the proton,
based on inclusive deep-inelastic scattering (DIS) and semi-inclusive DIS (SIDIS) data within a consistent
next-to-leading order (NLO) QCD framework.
In addition to existing measurements, we incorporate simulated pseudodata for the future Electron-Ion Collider (EIC),
considering two beam-energy configurations, $E_e \times E_p = 5 \times 41~\mathrm{GeV}$\textcolor{blue}{(or GeV$^2$?)} and $18 \times 275~\mathrm{GeV}$,
corresponding to an extended kinematic reach down to $x \sim 10^{-5}$.
We focus on longitudinal double-spin asymmetries $A_1^h$ for charge-separated pion and kaon production in SIDIS
off a longitudinally polarised proton target.
These projected measurements significantly improve the flavour separation of sea-quark helicity PDFs
($\Delta \bar{u}$, $\Delta \bar{d}$, $\Delta s$) and reduce the uncertainties on
both quark and gluon helicity distributions, with the largest impact at small $x$.
Polarised PDFs are extracted using a neural-network parametrisation and a Monte Carlo replica methodology to propagate
experimental uncertainties, while theoretical constraints such as positivity are imposed during the fit.
We demonstrate that the inclusion of EIC pseudodata leads to a substantially more precise determination of helicity PDFs,
with the largest impact in the small-$x$ region.
The resulting helicity-PDF sets are provided in the {\tt LHAPDF} format.
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