# Presentation: 878782

## MET Performance Studieswith Full Simulation

**Shuichi Kunori**
**U. of Maryland**
**7-June-2000**

## Issues

**MET Resolution**
- MET(x,y) = -(Ex(i),Ey(i))
- (MET) = a/(Et(i))1/2,        ( I: readout channel)
**Sensitive to **
- pile-up
- noise / dead channels
- threshold in readout
- LSB (L1: ~1GeV,  offline 0.2 GeV) ?
**How to improve?**
**Trigger**
**How low threshold can we go?**
**Limited by resolution for QCD events with zero MET.**

## MET in tH+

**(R.Kinnunen)**

**Offline MET cut**
**>100GeV**

## tH+ : Selection & Signal

**Assumed Trigger: 3 jets (Et>20GeV) plus tau-jet (Et>100GeV) **

## Offline MET Response

**(H->bb)**

## Offline MET Resolution

**QCD Jets with no neutrino/muon**

**Any way to improve this?**

**Ex = ******** (Ex-tower)**
**Ey = ******** (Ey-tower)**

**e.g.**
**Ex’=Ex+******** ( ********(Ex-jet))**
**Ey’=Ey+******** ( ********(Ey-jet))**

**(no pile-up)**

**Does this work?**

## Minimum Bias Event Overlap(in-time only)

**Minimum Bias Event Overlap****(in-time only)**

**X-sec = 55mb   >>>   17.3 min-bias/crossing    at 10E34**

**Et Flow**

**Scalar Et ( eta<5 )**

**~17 GeV in  unit (eta x phi) !**

**( equiv.  cone radius 0.56 )**

**<Scalar Et> = 1080 GeV**

**Note: <Scalar Et> = 750 GeV for ttH**

**(particles)**

## MET with Pile-up(eta 5 vs 7)

**MET with Pile-up****(eta 5 vs 7)**

**(S.Abdullin)**

**MET (GeV)**
**           ****gen.      cmsjet**
**eta                res.      all(*)**
**5       15.49  19.36   21.53   **
**7         5.21  12.92   17.80**
**(all = res. & B-field & vtx smearing)****  **

**~ Equal contribution from**
**eta 5-7,  resolution and B-field**
**  ****(15GeV)           (12GeV)                    (9-12GeV)**

**(CMSJET simulation)**

## CMSIM Simulation

**HF2:**
** ****Z=1613-1628-1748-1778cm**
**em      had       tail**
** ****Rin= 2.5cm, Rout=130cm**
** ****Material: Cu(W) + fibers**
** ****Segmentation**
**eta=0.348, phi=20deg.**
** ****Size**
**6.1x7.2cm at eta 5**
**:**
**1.1x0.9cm at eta 7**

## Rates with Pile-up(ORCA3)

**Huge rate below MET < 100 GeV**
**due to min-bias at 10E34.**

**(P.Hidas)**

**In-time pile-up**

**No pile-up**

## MET Threshold for 95% efficiency

**(P.Hidas)**

**Different ways to **
**calculate MET**** **

**Note:**
**H->tau+tau is**
**relatively low **
**jet multiplicity events.**

## MET for Signal Events with Pile-up and Tower Threshold

**ttH(110) with 17.3 min-bias events**

**No min-bias**

**Tower = Ecal+Hcal**

**GeV**

**>> Not much pile-up effect with this resolution!**
**>> Resolution gets worse as threshold increase.**

## MET and LSB

**tth(110)**
**with 17.3mb**

**1 GeV**

**0 GeV**

**LSB**

## Summary

**We just started studies of MET performance at 10E34. We have checked effects due to:**
**eta coverage and (in-time) pile-up**
**tower Et threshold / LSB**
**   ****=> Need to check effects due to non-linearity**
**algorithm for MET scale correction**
**Is there better way to calculate MET than simply using raw readout channels?**
**We may need various algorithm depending on final states.       --- using Jets, tracks, etc.   ???**
** **
**Suggest us challenging bench mark physics processes for offline and trigger MET!**
**HELP!**