1. Napoli  0  selection Selection is applied on all CHORUS located events Estimation of efficiency using the Hybrid simulation chain Comparison with the previous MC (without empty volumes) G. De Lellis, L. Scotto Lavina

2. ModuleLocated events 00 Selected 1109551814 111951300 2109222157 211144635011 310100522111 31113083059 410143541227 411148642728 5101027710 51113831472 61010471304 61113741544 71010481749 71110301632 8109582576 811114927611 scanning load: 4.8% of 0  located events 364*4=1456 events to manual scan over ~ 30 K events ModuleLocated events 00 Selected 1207601484 1211135330 220122333711 221203652630 320139330515 321192044628 420139943532 421165951532 520767692 5211080802 620153421314 621212526912 7209381474 721133718211 82063815511 821120424221 total396727615364 Selection on all CHORUS located events

3. Efficiency Module 0  processed Selected 51011022 51116117 52015116 521104 55014112 55113415 56018617 57023114 57113821 58014017 5811188 61012121 61112327 62014828 62115745 Efficiency = 22% strongly dependent on modules Module 0  processed Selected 65016830 65113120 66020742 66114630 67021743 67114025 68042 68110931 71011614 71114230 72014229 72119659 75015236 75113436 76021598 1424 events selected from 6500 DIS   0  located using Hybrid Simulation Chain Module 0  processed Selected 76115743 77021166 77117137 81011731 81116830 82014724 82117461 85013933 85110436 86018968 86116452 87018549 87116243 88012434 total65001424

4. Efficiency versus Stack Stack 4Stack 3Stack 2Stack 1 22% Efficiency

5. from Mickey-mouse simulation to Hybrid Simulation Chain Mickey-mouse SimulationHybrid Simulation Chain 49 %22 % The average efficiency is reduced by a factor 49/22 = 2.2 Selection efficiencies using DIS   0 

6. Conclusions and overlook The selection is applied to all CHORUS modules. 1.4 k events to be manually scanned over 30k NC located. Events already scanned by Sato’s selection to be subtracted There is a large numerical discrepancy between the first evaluation of the efficiency and the one obtained by Hybrid Simulation Chain The selection efficiency is 22%. Sato 0  selection is 23% (these numbers cannot be directly compared: the ratio evaluated in a homogeneous way is ~1.4). Combine the selections to increase the experiment sensitivity. We can afford the scanning.