Results from ATLAS Endcap Combined Testbeam Goal Study

Results from ATLAS Endcap Combined Testbeam Goal: Study response in particular difficult region with 3 calorimeters and additional support structures (‘dead material’) Set-up, data Electrons in EMEC and FCAL: response, calibration Electrons: vertical ( ) scans Pions in EMEC/HEC and FCAL: response on em scale Pions: vertical scans (em scale) Next steps Caveat: all data are very preliminary … analysis still in progress … Thanks to the ATLAS H 6 CTB collaboration, in particular to M. Bieri, P. Cavalleri, A. Minaenko, W. Shaw, P. Strizenec ! 1/19/2022 P. Schacht: Results from ATLAS Endcap Combined Testbeam 1

ATLAS Calorimeter: Endcap Region around η=3. 2 TILE HEC (Cu) EMEC (Pb) η=3. 2 FCAL (Cu, W) 1/19/2022 P. Schacht: Results from ATLAS Endcap Combined Testbeam 2

LAr Endcap Calorimeter ‘Inner EMEC Wheel’ EMEC wheel has 8 modules. . 1/19/2022 Each HEC (1 and 2) wheel has 32 modules. . P. Schacht: Results from ATLAS Endcap Combined Testbeam 3

LAr Forward Calorimeter FCAL 3 FCAL 2 FCAL 1 (em) ‘Cold cone’ 1/19/2022 P. Schacht: Results from ATLAS Endcap Combined Testbeam 4

Testbeam Set-up: Side View (CERN, H 6 Beam) HEC 1, 2 EMEC Beam FCAL ‘cold cone’ FCAL 1, 2 cryostat Goal: calibrate complicated region with various dead material zones and 3 different calorimeters 1/19/2022 P. Schacht: Results from ATLAS Endcap Combined Testbeam 5

Testbeam Set-up … in reality…during insertion Beam 1/19/2022 P. Schacht: Results from ATLAS Endcap Combined Testbeam 6

Testbeam Set-up: Front View, Data Electrons, Pions Energy 6200 Ge. V Vertical scans Horizontal scans Fixed points for energy scans 1/19/2022 P. Schacht: Results from ATLAS Endcap Combined Testbeam 7

Electron response in EMEC Gap variation HV variation in ! Try to compensate for response! -dependent correction: Ecorr=Ecell /(1+ ( cell- 0)) In consequence: and determined for each HV section from electron data! …very close to theoretically expected values…. 1/19/2022 P. Schacht: Results from ATLAS Endcap Combined Testbeam HV * =0. 55 for high and low * =1. 0 (high ) * =1. 04 (low ) 8

Electron response in EMEC Normalization done with electrons Rmax=0. 25 (5 5 cluster), almost no leakage outside cluster Check with electrons Rmax=0. 15 (3 3 cluster), few % out of cluster leakage …. . Checks done with y ( ) scans at different x ( ) positions and different energies …. . e 193 Ge. V e 119 Ge. V now constant, =0 1/19/2022 now constant, =0 P. Schacht: Results from ATLAS Endcap Combined Testbeam 9

Electron resolution of cluster in EMEC No dead material corrections; No correction, no out of cluster leakage correction yet; Noise subtracted! 3 3 cluster 5 5 cluster 1/19/2022 P. Schacht: Results from ATLAS Endcap Combined Testbeam 10

Electron resolution in EMEC (point B) Cluster (leakage) and correction; Noise subtracted! Sampling term: 15. 8 0. 1 % Constant term: 0. 5 0. 1 % Preliminary ! 1/19/2022 P. Schacht: Results from ATLAS Endcap Combined Testbeam 11

Electron linearity of cluster in EMEC No dead material corrections; No correction, no out of cluster leakage correction yet; 5 5 cluster 3 3 cluster 1/19/2022 P. Schacht: Results from ATLAS Endcap Combined Testbeam 12

Electron resolution of cluster in FCAL No dead material corrections; No out of cluster leakage correction yet; Noise subtracted! cone =0. 15 cone =0. 3 1/19/2022 P. Schacht: Results from ATLAS Endcap Combined Testbeam 13

Electron linearity of cluster in FCAL No dead material corrections; No out of cluster leakage correction yet; cone =0. 3 cone =0. 15 1/19/2022 P. Schacht: Results from ATLAS Endcap Combined Testbeam 14

Electrons (193 Ge. V): vertical scan at x=0 MC: Open squares; Data: solid points; sum FCAL 1 EME 2 MC: total energy! Data: 3 3 cluster! No correction! cold cone 1/19/2022 EME 3 P. Schacht: Results from ATLAS Endcap Combined Testbeam 15

Electrons: vertical scan at x=0; Geometry: crack in data wider by ~ 15 mm; ‘Double dip structure in crack‘: OK – EMEC-backsupport-ring+LAr and cold cone; Cold cone shifted by ~ 35 mm; Still in process of improving details of MC geometry and material structures; 1/19/2022 P. Schacht: Results from ATLAS Endcap Combined Testbeam 16

Pions in EMEC/HEC: em scale!!! Energy dependence of cluster; cone =0. 4 em scale! MC MC cone =0. 3 1/19/2022 P. Schacht: Results from ATLAS Endcap Combined Testbeam 17

Pions in FCAL: em scale!!! Energy dependence of cluster; MC cone =0. 4 em scale! cone =0. 3 1/19/2022 P. Schacht: Results from ATLAS Endcap Combined Testbeam 18

EMEC: Pions (200 Ge. V): vertical scan at x=-60; Data (200 Ge. V) solid points; MC (120 Ge. V) open squares; EMEC 2 em scale! EMEC 3 1/19/2022 P. Schacht: Results from ATLAS Endcap Combined Testbeam 19

HEC: Pions (200 Ge. V): vertical scan at x=-60; Data (200 Ge. V) solid points; MC (120 Ge. V) open squares; HEC 2 em scale! HEC 1 1/19/2022 P. Schacht: Results from ATLAS Endcap Combined Testbeam 20

FCAL: Pions (200 Ge. V): vertical scan at x=-60; Data (200 Ge. V) solid points; MC (120 Ge. V) open squares; FCAL 1 em scale! FCAL 2 cold cone 1/19/2022 P. Schacht: Results from ATLAS Endcap Combined Testbeam 21

Total: Pions (200 Ge. V): vertical scan at x=-60; Data (200 Ge. V) solid points; MC (120 Ge. V) open squares; em scale! 1/19/2022 P. Schacht: Results from ATLAS Endcap Combined Testbeam 22

Summary Ø em scale for all calorimeter subdetectors established; Ø electron results close to expectations! Ø MC geometry: from electron position scans small adjustment for next iteration required; Ø Pion response on em scale: close to MC Ø pion position scans: MC seems to give reasonable description of data (general trend), details yet to be clarified; Ø … many more things to do: go from em scale to scale; do e/ weighting using data and MC weights; compare energy tails in dead material with MC; do dead material corrections and compare with MC; and more to come ……. . 1/19/2022 P. Schacht: Results from ATLAS Endcap Combined Testbeam 23