The determination of track reconstruction efficiencies at LHCb using $J/\psi\rightarrow\mu^{+}\mu^{}$ decays is presented. Efficiencies above $95\%$ are found for the data taking periods in 2010, 2011, and 2012. The ratio of the track reconstruction efficiency of muons in data and simulation is compatible with unity and measured with an uncertainty of $0.8 \%$ for data taking in 2010, and at a precision of $0.4 \%$ for data taking in 2011 and 2012. For hadrons an additional $1.4 \%$ uncertainty due to material interactions is assumed. This result is crucial for accurate cross section and branching fraction measurements in LHCb.
Tracking detectors and track types reconstructed by the track finding algorithms at LHCb. 
lhcb.pdf [21 KiB] HiDef png [100 KiB] Thumbnail [52 KiB] 

Illustration of the three tagandprobe methods: (a) the VELO method, (b) the Tstation method, and (c) the long method. The VELO (black rectangle), the two TT layers (short bold lines), the magnet coil, the three T stations (long bold lines), and the five muon stations (thin lines) are shown in all three subfigures. The upper solid blue line indicates the tag track, the lower line indicates the probe with red dots where hits are required and dashes where a detector is probed. 
trackE[..].pdf [1 KiB] HiDef png [70 KiB] Thumbnail [33 KiB] 

trackE[..].pdf [2 KiB] HiDef png [66 KiB] Thumbnail [34 KiB] 

trackE[..].pdf [2 KiB] HiDef png [66 KiB] Thumbnail [34 KiB] 

Invariant mass distributions for reconstructed $ { J \mskip 3mu/\mskip 2mu\psi \mskip 2mu}$ candidates from the 2011 dataset. The solid line shows the fitted distribution for signal and background, the dotted line is the signal component. The subfigures are (a) the VELO method, (b) the Tstation method, (c) the long method. For comparison of resolution and signal purity (d) shows the invariant mass distribution of $ { J \mskip 3mu/\mskip 2mu\psi \mskip 2mu}$ candidates obtained with the standard reconstruction at LHCb. 
Velo_m[..].pdf [25 KiB] HiDef png [234 KiB] Thumbnail [194 KiB] 

Tstati[..].pdf [23 KiB] HiDef png [237 KiB] Thumbnail [196 KiB] 

Long_m[..].pdf [46 KiB] HiDef png [207 KiB] Thumbnail [170 KiB] 

Standa[..].pdf [36 KiB] HiDef png [232 KiB] Thumbnail [186 KiB] 

Track reconstruction efficiencies for the 2010 data and for weighted simulation. The lefthand column shows the results of the combined method while the righthand column shows the results of the long method. The efficiency is shown as a function of $p$ (first row), $\eta$ (second row), $N_{\rm track}$ (third row), and $N_{\rm PV}$ (fourth row). The error bars indicate the statistical uncertainties. 
combin[..].pdf [14 KiB] HiDef png [147 KiB] Thumbnail [150 KiB] 

Long_e[..].pdf [14 KiB] HiDef png [148 KiB] Thumbnail [148 KiB] 

combin[..].pdf [14 KiB] HiDef png [118 KiB] Thumbnail [124 KiB] 

Long_e[..].pdf [14 KiB] HiDef png [117 KiB] Thumbnail [122 KiB] 

combin[..].pdf [14 KiB] HiDef png [140 KiB] Thumbnail [141 KiB] 

Long_e[..].pdf [14 KiB] HiDef png [139 KiB] Thumbnail [138 KiB] 

combin[..].pdf [14 KiB] HiDef png [133 KiB] Thumbnail [135 KiB] 

Long_e[..].pdf [14 KiB] HiDef png [131 KiB] Thumbnail [132 KiB] 

Track reconstruction efficiencies for the 2011 data and for weighted simulation. The lefthand column shows the results of the combined method while the righthand column shows the results of the long method. The efficiency is shown as a function of $p$ (first row), $\eta$ (second row), $N_{\rm track}$ (third row), and $N_{\rm PV}$ (fourth row). The error bars indicate the statistical uncertainties. 
combin[..].pdf [14 KiB] HiDef png [142 KiB] Thumbnail [145 KiB] 

Long_e[..].pdf [14 KiB] HiDef png [145 KiB] Thumbnail [144 KiB] 

combin[..].pdf [13 KiB] HiDef png [115 KiB] Thumbnail [122 KiB] 

Long_e[..].pdf [14 KiB] HiDef png [116 KiB] Thumbnail [120 KiB] 

combin[..].pdf [14 KiB] HiDef png [134 KiB] Thumbnail [133 KiB] 

Long_e[..].pdf [14 KiB] HiDef png [132 KiB] Thumbnail [132 KiB] 

combin[..].pdf [14 KiB] HiDef png [125 KiB] Thumbnail [127 KiB] 

Long_e[..].pdf [14 KiB] HiDef png [123 KiB] Thumbnail [125 KiB] 

Track reconstruction efficiencies for the 2012 data and for weighted simulation. The lefthand column shows the results of the combined method while the righthand column shows the results of the long method. The efficiency is shown as a function of $p$ (first row), $\eta$ (second row), $N_{\rm track}$ (third row), and $N_{\rm PV}$ (fourth row). The error bars indicate the statistical uncertainties. 
combin[..].pdf [14 KiB] HiDef png [143 KiB] Thumbnail [146 KiB] 

Long_e[..].pdf [14 KiB] HiDef png [145 KiB] Thumbnail [146 KiB] 

combin[..].pdf [13 KiB] HiDef png [117 KiB] Thumbnail [123 KiB] 

Long_e[..].pdf [14 KiB] HiDef png [117 KiB] Thumbnail [121 KiB] 

combin[..].pdf [14 KiB] HiDef png [133 KiB] Thumbnail [135 KiB] 

Long_e[..].pdf [14 KiB] HiDef png [132 KiB] Thumbnail [133 KiB] 

combin[..].pdf [14 KiB] HiDef png [126 KiB] Thumbnail [129 KiB] 

Long_e[..].pdf [14 KiB] HiDef png [124 KiB] Thumbnail [127 KiB] 

Track reconstruction efficiency ratios as a function of $p$ between data and simulation for (left) 2010 data, (right) 2011 data, and (bottom) 2012 data. 
ratioP[..].pdf [14 KiB] HiDef png [116 KiB] Thumbnail [112 KiB] 

ratioP[..].pdf [14 KiB] HiDef png [106 KiB] Thumbnail [105 KiB] 

ratioP[..].pdf [14 KiB] HiDef png [108 KiB] Thumbnail [108 KiB] 

Animated gif made out of all figures. 
DP2013002.gif Thumbnail 
Settings of the software trigger selection as a function of data taking period. Only the tag muon is required to pass the selection. For more information see Refs. [26,27,28,9]. 
Table_1.pdf [37 KiB] HiDef png [67 KiB] Thumbnail [33 KiB] tex code 

Selection requirements on the tag and probe tracks and on the combination into a $ { J \mskip 3mu/\mskip 2mu\psi \mskip 2mu} $ candidate for the three different methods. 
Table_2.pdf [49 KiB] HiDef png [130 KiB] Thumbnail [64 KiB] tex code 

Track reconstruction efficiencies in % for the individual running periods using the long method for positive and negative muons and different magnetic field polarities (statistical uncertainties only). 
Table_3.pdf [49 KiB] HiDef png [71 KiB] Thumbnail [36 KiB] tex code 
Created on 14 September 2019.Citation count from INSPIRE on 14 September 2019.