Irshad Muzaffar Supervisors Prof Huang Guangshun Dr Zhou

Irshad Muzaffar 勤奋 Supervisors: Prof. Huang Guangshun 黄光顺 , Dr. Zhou Xiaorong 周小蓉 Department of Modern Physics University of Science and Technology of China

Outline ØMotivation ØData Analysis üEvent Selection üBackground Study (Next Plan) üComparison between Data and MC ØSystematic Uncertainty ØFit results ØSummary

Motivation •

Data Sets and MC Samples •

Event Selection •

Purpose of KMFit 1 And KMFit 2 •

Chi-Square Distributions After KM Fit 1 After KM Fit 2 Chisq 1: Chisq 2

Matching Angle of Neutral Tracks with MC Truth Neighboring showers from nbar If nbar_shower<40 And excluded all the selected anti-neutron, Then it can be remove easily.

Matching Angle of Neutral Tracks with MC Truth Gam_match 1<10 36% mis-matched (undetected & miscombine) Gam_match 2<10 21% un-detected Note: If nbar_shower<40 and Excluded all the Anti-Neutron showers, then it can be remove easily Anti-Neutron neighboring Shower.

Matching Angle of Neutral Tracks with MC Truth Gam_match 1>10&&neu_match 1<10 17% are from neutron (treated as photon) Gam_match 2>10&&neu_match 2<10 10% uncorrected matched (Minimum Angle)

KM 1: Matching Angle of selected Gamma with Anti Neutron

Matching Angle of Selected Anti-Neutron with MC Truth Nbar_macth<20 93% matched correctely

Energy Distributions of Gamma after KM Fit 1 &KM Fit 2

Methode 1: Rate of Cut Flow No. of Obs. Selection Criteria Survived Events Percentage Efficiency Total Efficiency 01. 02. 03. 04. 05. 06. 07. Total Number Charge Track cut EMC Shower cut Nbar Shower cut Pass PID Pass KM Fit 1 Pass KM Fit 2 330000 209221 167177 164422 158140 95638 93345 100 63. 40 80 98. 4 75. 9 58 55 100% 63. 40% 50. 7% 49. 8% 47. 9% 30% 28%

Purpose of KMFit 3 •

Chi-Square Distributions

Matching Angle of Neutral Tracks with MC Truth For Gamma: Gam_macth<10 68% matched correctly For Neutron: Gam_match 2<10&&neu_match>10 12% neutron treated as photon

Matching Angle of Neutral Tracks with MC Truth For Neutron: Gam_match 2>10&&neu_match<10 77 % matched correctly

Matching Angle of Selected Anti-Neutron with MC Truth Nbar_match<20 97% matched Correctly

Energy Distributions of Gamma

Methode 2: Rate of Cut Flow No. of Obs. Selection Criteria Survived Events Percentage Efficiency Total Efficiency 01. 02. 03. 04. 05. 06. Total Number Charge Track cut EMC Shower cut Nbar Shower cut Pass PID Pass KM Fit 1 330000 209221 104630 103747 99581 36712 100 63. 40 50 99 48 35 100% 63. 40% 31. 7% 31. 4% 30% 11. 1%