# Presentation: 671590

## G4 Hadron Shower and TB2004/2006HF and EB+HB

**S.Kunori**
**S.Piperov / T.Yetkin**
**03-Apr-2007**

**All slides are discussion purpose- all plots are preliminary.**

## Cerenkov detector- Sensitive to pi0’s

**Cerenkov detector- Sensitive to pi0’s**

## TB2004 HF

- 30GeV pi-

- 100GeV e-

- Reslolution – electron

- Long

- 100GeV   pi-

- Data vs G4

- Electron: Good agreement
- Cerenkov light production & collection and PMT simulation implemented correctly.
- Pion: LHEP agrees.
-  Others: too much pi0’s.

- (Taylan)

- 150GeV pi-

## HF (Long Fiber) Simulation  (G4  8.1 p02)

- HF: Quartz fiber calorimeter
-        Sensitive to pi0’s in hadronic shower
- LHEP still agree better with data.

**HF (Long Fiber) Simulation  (G4  8.1 p02)**

- 100GeV e- in HF (L)   p.e.    (rms)

- 100GeV pi-

-  HF response calibrated with 100GeV e-

- 100GeV e-

## ECAL +HCAL

**TB2004**

**ECAL: (PbWO4 Crystals) -   small 14x14cm         (TB2004),    **
**                                               ****a real super module (TB2006)**
**HCAL: brass (5cm) + scintillator (3.7mm) sampling**

## TB2004 HB

- Data vs G4

- LHEP - good agreement with data, except for p<10GeV.
- QGSP – shorter shower profile.

**2.8GeV**

**3.5GeV**

**1.8GeV**

**2.3GeV**

**ECAL**

**HCAL**

**HCAL**

## CMS TB2006

**CMS TB2006**

- This analysis used-
- ECAL: one barrel super module
-             PbWO4 Crystals
- HCAL: one barrel module
-             Brass-Scitillator sampling cal
- 1 – 350 GeV in H2 beam line
- Better P-ID and beam clean-up.

- ( ECAL, HCAL calibrated with 50GeV electrons )

## 5GeV pi-

**G4 Edep in ECAL**
**for 5GeV pi-**
**e+/e-          54%**
**pi+/pi-/..     13**
**p/pbar        17%**
**Ions           14%**

**Suppression of **
**Proton/pbar/ions**
**gives better agreement.**

## Multiplicity of Secondary Particles 

**n**

**p**

**ion**

**pi- / pi0**

**pi+**

**p**

**ion**

**QGSP-BERT**

**pi- / pi0**

**pi+**

**QGSP**

**Multiplicity of Secondary Particles **
**at First Interaction Point**

**Too much neutrons / protons / ions  ?**

**QGSP-BERT**

**ion**

## HCAL Alone

**TB2006 Data**

**G4 (****6.2****, ****7.1****) for TB2004 setup**

**Seen in sampling calorimeter !**
**Energy spectrum also too hard?**

**Ignore this line**

**e-**

**pi-/+**

**p**

- (HO included)

- (no HO)

## Suppression of protons/ions

**ECAL+HCAL**

**QGSP-BERT > QGSP**
**Ions and protons are ignored in Edep calculation to suppress those effectively. **
**Can we tune hadrons shower simulation in this way?**

## Conclusion

**Comparison with HF TB04**
**LEHP still shows the best agreement with data.**
**p.e. increased by 25% in LHEP 4-1.**
**Comparison with ECAL+HCAL (TB04/TB06)**
**No update on longitudinal shower profile (yet)**
**Seeing excess energy in G4 below 10GeV**
**Small difference can be explained by Birks’ law and cerenkov lights in crystals. But observed difference is too large.**
**Waving shape below 10 GeV is unphysical.**
**Too much slow protons/ions?**
**Tuning – two ways**
**Ignore slow protons and ions in calorimeter simulation**
**Get smooth curve in 1-300GeV**
**Fix G4 physics model(s).**
**Problem already reported to the G4 hadron physics group.**
**Discussion started (yesterday).**