# Presentation: 242698

## Why do we need Jet-id ?
      Because there are noise/fake jets
What are the Noise/Fake jets ?
Noise jets   (partly cured by on-line/off-line Data quality corrections)
Fake jets are overcalibrated “jets” (either by picking up noise, or in difficult regions like ICR)
What are the handles we have ?
Precision readout  estimators like EMF, F90 
L1 information  allows confirmation (in p14)
Tracking   also better in p14
CPS   in p14.05
T42  (as a byproduct)  in d0correct

**      ****Because there are noise/fake jets**
**What are the Noise/Fake jets ?**
**Noise jets   (partly cured by on-line/off-line Data quality corrections)**
**Fake jets are overcalibrated “jets” (either by picking up noise, or in difficult regions like ICR)**
**What are the handles we have ?**
**Precision readout ******** estimators like EMF, F90 **
**L1 information ******** allows confirmation (in p14)**
**Tracking  ******** also better in p14**
**CPS  ******** in p14.05**
**T42  (as a byproduct) ******** in d0correct**

**Jet-id / Fake Jets / T42**

**G. Bernardi for CALGO (thanks to the Top group)**

## Jet-ID Definitions

_**JID:**_** electron removal, 0.05<EMF<0.95, HOTF<10, CHF<0.4, N90>1**
_**JID-f90:**_**    JID  and  ( if f90 < 0.5  or  CHF  < 0.15 )**
_**L1:**_**       JID and**
**	****	****  ****	****((CC or EC) and L1SET/pT >0.2**
**	****	****             ****or ICD     and L1SET/pT >0.1)**
_**Track:**_**  JID and Sum tracks**** ****in 0.5-cone pT / jet pT > 0.05**
_**L1/Track:**_**   L1 in CC and EC, Track in ICD**
_**L1+Track:**_**   L1/Track  + Track in CC**
_**Perfect jets: **_**   L1+Track                                     ( 1)**
_**Bad jets :**_**         no L1 , no Track, JID                  (-1)**
_**Ugly jets:**_**         no L1, no Track,  JID                  (-2)**
_**Rest:**_**    which includes “good” jets (JID-f90)   ( 0)**

## Number of bad/good  Jets in 50k dijet sample

**all     erem  hotf emf> emf<  n90   JID    f90   L1    L1&T  L1/T   or     L1t   Track   coml comt**
**8118 8108 8105 7951 7938 7937 7738 5310 5089 3851 4557 4967 4849 4337 4810 4570**
**6544 6535 6533 6488 6480 6479 6347 4438 4224 3290 3839 4166 4034 3674 4052 3862**
**2797 2790 2789 2753 2731 2730 2725 2552 1896 1516 1789 1882 1830 1659 1860 1794**
** ****231   230   229   219   217   217   184   117   125     93   113    124   121   109   121   117**
** **
**188   187   186   177   175   175   151     97    103     79     94      99    100     90     98     95**
** **
**   ****95     93     93     89     83     83     82     78      54     39     49      53     52      46     53     51**
** **
**1499 1463 1462 1453 1431 1431 1401 1311 1394 1249 1338 1374 1388 1255 1374 1368**
**1138 1111 1110 1102 1085 1085 1063 1007 1058   953 1019 1043 1055   958 1043 1040**
**1296 1239 1239 1233 1222 1222 1212 1184 1203 1086 1166 1198 1202 1093 1197 1196**

**dijet: **
**dijet_GRL: **
** **
**djT42GRL: **

** ****dijet: **
** **
**dijet_GRL: **
**diT42GRL: **

**dijet:**
**dijet_GRL:  **
**djT42GRL: **

**black: bad jets from high jet multiplicity**
**green: bad third jet in dijet event**

**blue: good dijet events**
**GRL = good run list applied**

***Bad Jets***

***Bad Jets***

***Good Jets***

## Efficiencies for bad/good  Jets in 50k dijet sample

** **
** ****100  99.9  99.8  97.9  97.8  97.8  95.3  65.4  62.7  47.4  56.1  61.2  59.7  53.4  59.3  56.3**
** **
** ****100  99.9  99.8  99.1     99     99     97  67.8  64.5  50.3  58.7  63.7  61.6  56.1  61.9     59**
** **
** ****100  99.7  99.7  98.4  97.6  97.6  97.4  91.2  67.8  54.2     64  67.3  65.4  59.3  66.5  64.1**
** ****100  99.6  99.1  94.8  93.9  93.9  79.7  50.6  54.1  40.3  48.9  53.7  52.4  47.2  52.4  50.6**
**  **
** ****100  99.5  98.9  94.1  93.1  93.1  80.3  51.6  54.8     42     50  52.7  53.2  47.9  52.1  50.5**
** **
** ****100  97.9  97.9  93.7  87.4  87.4  86.3  82.1  56.8  41.1  51.6  55.8  54.7  48.4  55.8  53.7**
** ****100  97.6  97.5  96.9  95.5  95.5  93.5  87.5     93  83.3  89.3  91.7  92.6  83.7  91.7  91.3**
**  **
** ****100  97.6  97.5  96.8  95.3  95.3  93.4  88.5     93  83.7  89.5  91.7  92.7  84.2  91.7  91.4**
** ****100  95.6  95.6  95.1  94.3  94.3  93.5  91.4  92.8   83.8     90  92.4  92.7 84.3  92.4  92.3**
**  **

**black: bad jets from high jet multiplicity**
**green: bad third jet in dijet event**

**blue: good dijet events**

**dijet: **
**dijet_GRL: **
** **
**djT42GRL: **

** ****dijet: **
** **
**dijet_GRL: **
**diT42GRL: **

**dijet:**
**dijet_GRL:  **
**djT42GRL: **

***Bad Jets***

***Bad Jets***

***good Jets***

**Efficiencies for bad/good  Jets in 50k dijet sample**

## Conclusions on jet-id / fake&noise jets

_**Some properties of the noise jets:**_
**low pT, sit mainly in the ICD and CH**
**fake high met, large HT and high jet Multiplicity**
**-> the noise is found where we look for interesting physics**
**In p13 LP03 sample **_**only 45 highest ET towers:**_
**-> much lower efficiency to find L1 confirmed jets!**
_**T42:**_
**50% reduction of bad jets**** **
****
**Use T42 and  Use L1 confirmation for Jet-id. **
**Use Tracks to monitor jet-id efficiencies**
**	****	****	****But....**

##            “tmb-fixed” W sample

**           “****tmb-fixed” W sample**

**P13**

**P13 with TMB fix and T42**

**  ****Em-id:**
** ****Em Fraction > 0.90**
** ****Isolation < 0.15**
** ****Em HM8 < 20**
** ****|********| < 1.1, In Fiducial vol.**
** ****p****T****e**** > 20 GeV**
**ME****T ****> 25 GeV**

**Standard Jets Criteria:**
** ****Em Fraction < 0.95**
** ****HOTF < 10**
** ****f90 < 0.5 or CHf<0.15****    **
**|********| < 2.5**
** ****P****T**** > 15 GeV**

** ****(left: loose elec.sel.**
**right: tight elec. sel.)**

## Missing ET , W Transverse Mass

**Missing E****T**** , W Transverse Mass**

**P13**

**P13 with TMB fix and T42**

## Eta of Leading Jet

**P13**
** ****(left: loose elec.sel.**
**right: tight elec. sel.)**

## Reducing influence of Noise: T42T42:   reject ALL isolated  cells below 4 sigmas (and ALL negative energy cells)  

**Select high signal cells (4 sigma)**
**Keep their significant neighbours (2 sigma ********Thresholds 2******** is 2.5******** at the moment  ******** T42.5**

**Full description is available in D****Ø****Notes 4124, 4146**

**Available in D0Reco in shadow mode**
**Not running yet: **
**We wants to have first a tmbfix           w/o T42**

## T42 on  high energy electrons

**T42 on  high energy electrons**

**Estimators for EM candidates in data, when pT>13 GeV**

**OK !**

## T42 on Missing and Scalar ET

**WZ skim , p13.06 , W******** e nu selection (E****T ****> 20 GeV, MET > 25 GeV)**
**Compared to Pythia MC**

**No T42**

**After T42**

##   Run Selection with T42

**Define the average shift:**** **
**     ****MET-xy = sqrt [ (<MET-x>)****2**** +(<MET-y>)****2****]                          RMS-xy = sqrt [ ( RMS-x )****2****   +  ( RMS-y )****2  ****]**** **
**To declare a  RUN  ****“GOOD”:**
**1) Require ****            ****MET-xy <   6  GeV in all files of a run,                                 ****	****	****  ****and MET-xy <   4 GeV in average**** **
**2) Require             ****RMS-xy < 18  GeV in all files of a run****	****	****	****            ****and  RMS-xy < 16  GeV in average**
**3) Require             ****scalar E****T****  > 70 GeV in all files of a run****  ****                                         ****	****           and  scalar E****T **** > 80 GeV**
**    ****Compare Run selection with and without T42       ****	****	****	****   on 55 pb****-1 **** of p14.03 data**

## T42 is “cleaner”

**Met-xy Shift**
**P14.03.02**
**Met-xy Shift**
**With T42**
**Scalar E****T**
**P14.03.02**
**Scalar E****T**
**With T42**

**T42 is “cleaner”**

## xy-shift in Missing ET,  xy-rms

**P14.03**
**Jul-Aug 2003 **
**one entry / good “file”**
**(about 20 lumi blocks)**
** **
**Same p14.03 files **
**but processed with**
**	****T42**

**xy-shift in Missing E****T****,  xy-rms**

## Scalar and Missing ET (setb,metb) 

**Jul-Aug 2003 **
**one entry / good “file”**
**(about 20 lumi blocks)**
** **
**Same p14.03 files **
**but processed with**
**T42**

**Scalar and Missing E****T**** (setb,metb)**** **

## Summary

**We are progressing !**
**The potential of  p14 is large after all the fixes.**
**Finalize the jet-id ******** JES can start**
**Watch ICD behavior**
**Use T42(.5)   (prepare T42 for restart)**