\label{sec:datatheory}

In this section, we discuss the experimental data that
is used in modern global PDF analysis, as well as the status of the corresponding
theoretical calculations and fast interfaces for their
inclusion in the PDF fits.
%
For each process, we discuss first the PDF sensitivity, then
the available data and state-of-the-art theory calculations,
and finally illustrate its impact on PDFs.
%
We start with a general overview of the datasets that are available
for PDF studies and then we move to discuss each process
separately, starting from DIS and then moving to inclusive jet
and weak boson production, the $p_T$ of $Z$ bosons, direct
photon, top-quark pair production, and charm production, among others.
%
In the last part of this section we discuss the technical but highly important topic
of fast (N)NLO interfaces, allowing the efficient inclusion of higher-order calculations
in PDF fits.

While the list of processes described in this section focuses
on those that have demonstrated so far
to provide the most
important constraints for PDF determinations, is not certainly not
exhaustive.
%
Beyond these, some processes that have been advocated to pin down
PDFs but are not discussed here further, such
as $W$ and $Z$ boson production in association with jets
and their ratios~\cite{Malik:2013kba}, among others.

\subsection{Overview}\label{sec:datatheory.overview}
\input{3-datatheory/subsec-overview}

\subsection{Deep-inelastic scattering}\label{sec:datatheory.DIS}
\input{3-datatheory/subsec-dis}

\subsection{Inclusive jets}\label{sec:datatheory.jets}
\input{3-datatheory/subsec-jets}

\subsection{Inclusive gauge boson production}\label{sec:datatheory.gauge}
\input{3-datatheory/subsec-DY}

\subsection{The $p_T$ distribution of $Z$ bosons}\label{sec:datatheory.zpt}
\input{3-datatheory/subsec-ptz}

\subsection{Direct photon production}\label{sec:datatheory.photon}
\input{3-datatheory/subsec-photons}

\subsection{Top quark production}\label{sec:datatheory.top}
\input{3-datatheory/subsec-top}

\subsection{Charm production in $pp$ collisions}\label{sec:datatheory.charm}
\input{3-datatheory/subsec-charm}

\subsection{$W$ production in association with
charm quarks}\label{sec:datatheory.Wcharm}
\input{3-datatheory/subsec-wcharm}

\subsection{Central exclusive production}\label{sec:datatheory.CEP}
\input{3-datatheory/subsec-CEP}

\subsection{Fast interfaces to (N)NLO calculations}\label{sec:datatheory.fast}
\input{3-datatheory/subsec-fast}

