Status of CEPC HCAL Optimization Study in Simulation LIU Bing On behalf the CEPC Calorimeter working group

Outline The introduction of the CEPC Calorimeter(SDHCAL, AHCAL, dual readout…) HCAL Optimization based on simulation(Mainly done by Jifeng) Software versions and samples Geometry structure Performance Particle identification optimization in SDHCAL BDT applied in Particle ID Conclusion

PFA and Imaging Calorimeter For future colliders, jet energy resolution will be a determinant factor of understanding high energy physics. magnet yoke and muon system Simulation of W, Z reconstructed masses in hadronic mode. 60%/E 30%/E To improve on the jet energy resolution PFA is a promising solution to reduce the confusion term  high granularity Calorimeters

Options: SDHCAL based RPC the first technological prototype among a family of prototypes of high-granularity calorimeters Total Size:1.0x1.0x1.4m3 Total Layers: 48 Total Channel(pads):440000 Power consumption:𝟏𝟎𝝁𝑾/𝒄𝒉𝒂𝒏𝒏𝒆𝒍 ASIC HARDROC(64 channel) three-threshold (Semi-digital) 110fC,5pC,15pC

SDHCAL based on RPC GRPC advantages: homogenous, cost-effective, negligible dead zone allow high longitudinal and transverse segmentation

HCAL optimization

Why HCAL optimization matters By Manqi Both physics goals and budgets require geometry optimization. ECAL and HCAL are two essential components for gamma/lepton/jets reconstruction and identification.

Software Version and Samples Software versions, Simulation: Mokka-08-03 revised Reconstruction: Arbor_KD_3.3 plus track-related processors Digitization : G2CDArbor Samples, 𝒆𝒆→𝒁𝑯→𝒍𝒍 𝒍𝒗𝒒𝒒@ 𝒔 =𝟐𝟓𝟎 𝑮𝒆𝑽 𝒆𝒆→𝒁𝑯→𝒃 𝒃 @ 𝒔 =𝟐𝟓𝟎 𝑮𝒆𝑽 𝒆𝒆→𝒁𝑯→𝒈𝒈@ 𝒔 =𝟐𝟓𝟎 𝑮𝒆𝑽

Geometry of HCAL Longitudinal profile Transverse profile Barrel Endcap R min (mm) R max (mm) Z min (mm) Z max (mm) Barrel 2058 3376 2350 Endcap 226 3280 2650 3948 By default, number of layers is 48, RPC based detector.

Jet Energy Deposition in HCAL 𝒆𝒆→𝒁𝑯→𝒃 𝒃 @ 𝒔 =𝟐𝟓𝟎 𝑮𝒆𝑽, 1E5 Events Detector class <=Ecal =HCAl <=HCAL Jet Energy Deposit ratio 60% 20% 92%

Jet Energy Deposition in HCAL Fraction of jet energy deposition Jet energy distribution The energy deposition fraction arrive at a plateau~23% for jet energy>80GeV

Jet Energy @Higgs measurement Higgs->gg 40 Layer for HCAL is reasonable

Jet Energy @Higgs decay branch ratio 𝒆𝒆→𝒁𝑯→𝒍𝒍 𝒍𝒗𝒒𝒒@ 𝒔 =𝟐𝟓𝟎 𝑮𝒆𝑽 40 Layer is a good choice

Particle identification in SDHCAL

Particle identification using BDT in SDHCAL BDT 6 var Input: First layer of the shower(Begin) Number of tracks in the shower (TrackMultiplicity) Ratio of shower layers over total fired layers(NInteractinglayer/Nlayers) Shower density(Density) Shower radius(Radius) Maximum shower position(Length) Density Radius Shower layers / fired layers Trackmultiplicty Shower Length Begin

Strong separation power in Training and Test MC samples training TMVA of root, Methods: BDT 6var Training and Test Signal: 160000 pion events with energy 10,20,30,40,50,60,70 and 80GeV Background:160000 electron events with energy 10,20,30,40,50,60,70 and 80GeV Background: 120000 muon events with energy 10,20,30,40,50,60,70 and 80GeV Mixed Background Ntraining : Ntest=1 : 1 Strong separation power in pi/e and pi/muon

Pion eff vs Bkg rejection rate MC samples training Good pi/e and pi/muon separation High pion efficiency exceeding 99% with electron and muon rejection of the same level (>99%)

Particle identification using BDT @Beam data validation SPS 2015 electron 10,20,30,40 and 50 GeV Pion 10,20,30,40,50,60,70,80GeV Muon 110 GeV The beam data also show the performance of pi-e and pi-mu separation are good .

Comparison with standard selection energy reconstruction

Particle identification using BDT in SDHCAL

Conclusion HCAL Optimization one option of CEPC Calorimeter:SDHCAL Several benchmark Higgs decay channels have been studied under different calorimeter configurations For Higgs->bb ,Higgs->gg, Higgs->WW analysis, JER and W mass are not sensitive to the number of HCAL layer after 40 Layers one option of CEPC Calorimeter:SDHCAL SDHCAL provide a powerful high granularity tool for the PFA leading to an excellent energy resolution. PID using BDT is reliable: Good pion efficiency with high electron and muon rejection rate

YES, the End, Thanks for your attention

Backup

Comparison with standard selection In the low energy, Using BDT save many events.