| 
		
			| Problems with new GEM Geometry [message #22477] | Tue, 17 April 2018 11:22  |  
			| 
				
				
					|  Tobias Stockmanns Messages: 489
 Registered: May 2007
 | first-grade participant | From: *ikp.kfa-juelich.de 
 |  |  
	| Dear PandaRooters and GEM experts, 
 in the analysis of the reaction: pbar p -> Xi Xibar pi pibar -> 3 pi 3 pibar p pbar we see a significant drop in the reconstruction efficiency depending on the GEM geometry we use. With the old geometry (gem_3Stations_Tube.root) we get 18.3% (15.2% MCTruth matched) of reconstructable events with all final state particles in the event, while with the new geometry (gem_3Stations_realistic_v2.root) this value drops to 6.4% (4.3% MCTruth matched).
 
 It is not clear if this is a real effect of the additional material introduced by the more realistic description of the GEMs or if there is still a bug in the geometry description which causes the drop of a factor 3.
 
 It would be great if an expert on the GEMs could have a look.
 
 Cheers,
 
 Tobias
 |  
	|  |  | 
	|  | 
	|  | 
	|  |