BNL Experiment STAR PMD - Track and Cluster


	Track and It's Clusters

Track and It's Clusters

	How are track position and it's corresponding cluster position related ? Ideally the cluster should have the same eta and phi or X and Y position as it's track. If you take the difference between track eta and it's cluster eta or track phi and it's cluster phi, it should be Zero. But practically it may not be so. This may be due to the following reasons : (i) Upstream materials in front of PMD (ii) Limiations of the clustering algorithm Since one of the main measurent in PMD is the spatial distribution of photons, it is crucial to see if we have most of photon clusters at the same position as it's track. CLICK ON THE FIGURES This plot shows the difference between track eta and corresponding cluster eta (both split and original) as well as the difference between track phi and corresponding cluster phi (both split and original) If you want to have a look at the best case possible - then look at these plots for PMD only case (that is there are no other detectors ON in simulation) CLICK ON THE FIGURES The above plot in log scale may be misleading, so please have a look at this plot. These plots show the percentage of tracks within certain delta eta and delta phi. We find that within delta eta < 0.2 there are 90 % of the tracks, and within delta phi 3 degree we have 80% of the tracks. For a condition combining the two we have the following, delta eta < 0.1 and delta phi < 2 deg ==> 71% of the tracks, delta eta < 0.2 and delta phi < 4 deg ==> 81% of the tracks, delta eta < 0.3 and delta phi < 6 deg ==> 85% of the tracks. If you want to have a look at the best case possible - then look at these plots for PMD only case (that is there are no other detectors ON in simulation)


Last modified Tuesday 15 February 2000 by Bedanga Mohanty [bmohanty@veccal.ernet.in]