Current Status of EMC Reconstruction He Miao 2005/7/21

outline EMC reconstruction event model . Data flow. Energy correction. Position correction. EMC end-cap reconstruction algorithm. Beam-test data analysis with EMC reconstruction package and improvement.

EMC reconstruction event model EmcRecDigit EmcRecID, EmcRecADC, EmcRecTDC EmcRecHit EmcRecID, EmcRecEnergy, EmcRecTime EmcRecFraction : public EmcRecHit EmcRecFrac EmcRecCluster EmcRecID, EmcRecHitMap EmcRecShower EAll, ESeed, E3x3, E5x5, Position, NearestSeed

Data Flow Digit Hit Cluster Shower Input: Emc Digit TDS Output: Emc Rec Shower TDS Root Emc Mc Hit

Energy correction

Test of EMC reconstruction package theta position σtheta≈6mm

Test of EMC reconstruction package phi position σphi≈6mm

Position correction correction parameters σ=4.1mm

Digitization Non-uniformity of Light Output Photo statistics Background Electronics noise

EMC end-cap reconstruction algorithm Cluster finding Neighbor definition: 3×3 Red, green and blue are neighbors. Hitmap output j-1 i-1 i,j i+1 j+1

Cluster finding end-cap 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1

Cluster finding endcap Sector i+1 Sector i 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1

Cluster finding endcap Sector 3 Sector 4 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 20mm gap

Hitmap barrel theta phi

Hitmap endcap

Hitmap endcap 29 28 27 26 25 24 23 22 21 20 19 18 * 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 Hit between two sectors

Beam-test data analysis Beam-test result Test2 - 6×6 matrix – April Test3 - 3×3 matrix Test3 - 5×5 matrix Test4 - 6×6 matrix – with MDC Splitting algorithm Time information

Test3 - 5×5 matrix 3×3,σE/E=2.92% 5×5,σE/E=2.95% In boss, σE/E=3.65%

Split shower with distance to seed r13=sqrt(x13^2+y13^2) r23=sqrt(x23^2+y23^2) e3=e3*weight1/weight_total +e3*weight2/weight_total weight1=e1*f(r13) weight2=e2*f(r23) f2(r)=exp{-a*r/Mr} Mr: Moliere radius=3.8cm a: constant=2.5 e1 e3 e2 e3=e3*e1/(e1+e2) +e3*e2/(e1+e2)

Split shower absolutely A hit belongs to nearest seed. A hit whose distances to each seed are equal will be shared. Take seed’s energy as weight. e1 e2

Split shower with distance to seed Split shower absolutely σE/E=2.96%

Time information time 18 - 24 3.29% 14 - 30 3.10% 10 - 40 3.11% 0 - 60 resolution 18 - 24 3.29% 14 - 30 3.10% 10 - 40 3.11% 0 - 60 3.13%

Reconstructed showers No time information 154540 t:14-30 split in hit 119731 t:18-24 split in shower 109645 t:14-30 split in shower 118776

Conclusion of beam-test analysis The improvement of splitting algorithm give better result (σE/E=2.94%) than before (σE/E=3.65%) , but not good enough. Time information is important for background exclusion. More research should be done.

Thank you!