In situ Et Miss scale determination from Z

In situ Et. Miss scale determination from Z lept-had channel Hadronic Calibration Workshop Munich - May 06 D. Cavalli 1

Z° lept-had channel study : Rome samples used Þ Signal Z° (DS 4807 and 4801) (~30 Kevts each corresp to~210+100 pb-1) decaying to everything - filter cuts: visibility of leptons and jets and ( ) cut (4807 has larger cut) Þ Backgrounds • From TDR: W+jets (dominant) and bb (~ 30 %) bb NOT PRODUCED for Rome No W+jets for Rome Þ Inclusive W e (DS=4203) (~50 Kevts corresp to 5 pb-1) Þ Inclusive W (DS=4204) (~100 Kevts corresp to 10 pb-1) ~ 20 % evts with at least 1 jet with p. Tjet > 15 Ge. V Þ top (DS=4100) (~50 Kevts corresp to 110 pb-1) NOT used the complete samples because of problems before and also after Rome in finding/transferring files (AOD and CBNT) all backgds should be produced in CSC Hadronic Calibration Workshop Munich - May 06 D. Cavalli 2

Z° lept-had channel : mass for Signal and Backgrounds with 10 fb-1 Applied cuts : pt(jet) > 25 Ge. V, | |<2. 5 pt(lep) > 25/20 Ge. V, | |<2. 5 is. EM & 0 x 7 FF) ==0 , <> ~ 90 ~ 14 lep isolation: Etcone 30<5 ge. V 1. < < 2. 7 or 3. 6< <5. 3 m. T(lept-p. Tmiss)<50 Ge. V -likelihood > 8 ( -eff ~ 30%) 66<rec m <116 Ge. V Expected in 10 fb-1 ~ 9000 evts with ~ 20% backgd Lowering pt thresholds: pt(jet) > 20 Ge. V, | |<2. 5 pt(lep) > 15 Ge. V, | |<2. 5 ~ 25000 evts with 30% backg Results still preliminar due to low bacgd statistics But more severe cuts necessary to reduce bb backgd? Need to have also a bb sample p. Tmiss>20 Ge. V Cuts tuning No pileup yet! Hadronic Calibration Workshop Munich - May 06 m. T(lept-p. Tmiss)<25 Ge. V D. Cavalli 3

Z° lept-had channel : Et. Miss Scale sensitivity of the measured Z° mass to the absolute Et. Miss scale preliminar plotted errors correspond to ~ 1000 evts A variation of +/- 10 % of the Et. Miss scale results in a shift of about 3% of the measured Z° mass Hadronic Calibration Workshop Munich - May 06 D. Cavalli 4

Backup slides Hadronic Calibration Workshop Munich - May 06 D. Cavalli 5

Commissioning: Z° lept-had channel study invariant mass reconstruction from decay products Generated 1 <> ~ 91. 1 ~2 2 <> ~ 90. 5 ~ 4. 3 3 Et. Miss and Rec Et. Miss Rec Eff ~ 86 % 4 Truth | |< 5 Truth <> ~ 90. 1 ~ 16. 2 5 p. T(lept) > 15 Ge. V, p. T( ) > 15 Ge. V, < 2. 7 , > 3. 6 <> ~ 91. 5 to kill back-to-back ~ 9. 5 evts causing large tails Et. Miss, and /e Rec G 3 -H 1 calib in 10. 0. 1 corr fact =1. 12 Eff ~ 90 % <> ~ 89. 4 ~ 16. 1 6 <> ~ 89. 9 ~ 16 Main contributions to the width : (2) Assumption on -decay prod dir , (3) Coverage effect , (4) Et. Miss Resol Hadronic Calibration Workshop Truth matching of reconstructed , , e D. Cavalli Munich - May 06 6

Event in mass bin strict cuts Event in mass bin after cuts Z° lept-had: Evts exp in 10 fb-1 after Analysis cuts Signal & Backg Þ Signal Z° lept-had (250 sim evts after cut 13) Þ Inclusive W e (40 ) , W (DS=4204) (6) Þ top (100) Due to the low statistics of backgrounds, the t-id (cut 7) on backgrounds is not applied (t-id factorized) (t-id factor NOT applied in the plot) Hadronic Calibration Workshop Munich - May 06 D. Cavalli 7

Event in mass bin strict cuts Event in mass bin after cuts Z° lept-had: Evts exp in 10 fb-1 after Analysis cuts Signal & Backg Þ Signal Z° lept-had (250 sim evts after cut 13) Þ Inclusive W e (40 ) , W (DS=4204) (6) Þ top (100) Due to the low statistics of backgrounds, the t-id (cut 7) on backgrounds is not applied (t-id factorized) (t-id factor NOT applied in the plot) Hadronic Calibration Workshop Munich - May 06 D. Cavalli 8