In a previous post, I defined the variable N(live) for track/pi0 clusters. I was initially using tracks that were owned by the cluster, i.e. tracks that passed the seed and shoulder pT thresholds. I wanted to see what effect these thresholds have on the N(live) distribution.
The plot below compares the N(live) distribution using owned tracks (in red) and all tracks within the dR threshold of the cluster, in this case dR=0.5, w.r.t. the seed track. This plot was made on the signal MC sample and required that a generator level tau must be present inside the cluster.
As expected, when counting all tracks the mean of the distribution increases. The increase is relatively small for these tau-tagged signal MC clusters; the mean goes from 2.52 to 2.89. We didn’t expect this to be a huge effect for clusters coming from taus, as they should have relatively few tracks. The effect is more dramatic when comparing to the W+jet background, as seen in the plot below.
We achieve much better separation in the N(live)=1,2,3 bins when using all tracks in the event to calculate it.
–Dan
