First estimation rejection for the Emcal electron trigger in pp Collisions.

In order to estimate the event rejection, a MC production on the GRID was used, LHC11b10a (pp MB 2.76 TeV). About 1.6 million events were analyzed on the GRID.

1 - Cluster Energy Rejection estimation

In order to evaluate the cluster energy rejection estimation, The cluster energy of the reconstructed clusters was used. The events which have at least one cluster with energy over the threshold imposed was considered as selected by the trigger.

The calculations here do not count the effects of fake trigger and the trigger efficiency factors, which can be important in the region close to the threshold.

2- Emcal Electron trigger

For the tracking matching, it was used the same method as we would like to implement on HLT, which is called RecoUtils::ExtrapolateTracktoCluster. It was considered as good matches dEta(track-cluster)<0.05 and dPhi(track-cluster) <0.05.

For the electron identification, it was used a E/P cut(0.8<E/P<1.2).

3 - Results

The figure 3.1 shows the event rejection for ClusterEnergy, ClusterEnergy+EMCal Electron and ClusterEnergy+EMCal Electron+SPDany(for reducing conversions).

Figure 3.1 - Event Rejection as a function of Cluster Energy threshold

If one assumes a collision rate= 100KHz, the input for HLT would be those shown in figure 3.2

Figure 3.2 - HLT Input for 100kHz Interaction Ratio

As a consequence, for the HLT output one obtains:

Figure 3.3 - HLT Output for 100kHz Interaction Ratio

-- MarcelFigueredo - 09-Aug-2011