datasets.tex

\section{Datasets}
\label{sec:datasets}

The measurement of the $\Upsilon$ production cross section is based on proton-
proton collision data collected with the LHCb detector at 7 and 8\tev
center-of-mass energies in 2011 and 2012, with corresponding integrated luminosities
of 1\invfb and 2\invfb.

\subsubsection{Signal MonteCarlo}

A full event and detector simulation is used for signal studies, and to
estimate the photon reconstruction efficiency. The event samples were
generated with the LHCb tune of Pythia\cite{LHCb-PROC-2010-056}, followed by a
full Geant\cite{Allison:2006ve} event simulation and LHCb reconstruction.

All \chib mesons are produced unpolarized. The effect of the initial unknown polarization 
will be taken into account by event reweighting and a systematic uncertainty will be assigned.  
During the event simulation the products of \chib decays are required
to have their momentum pointing into the angular acceptance of \lhcb. This
requirement is referred to as the generator cut. Only events that have passed this
requirement were saved and subsequently reconstructed.

The simulation was performed for both 7 and 8\tev operating conditions. In
total $6.2\times10^7$ events for all signal modes (\chib decaying to $\Upsilon
\gamma$) and magnet polarities were simulated and stored for subsequent
analysis. \Cref{tab:nmc} shows the number of simulated events for each decay
mode.


\input{tables/datasets/nmc}

The procedure to estimate the
reconstruction efficiency is described in detail in~\Cref{sec:mc:eff}.