# Presentation: 516275

## Status of the Higgs Sensitivity Study

**Status of the Higgs ****Sensitivity Study**

**Boaz Klima**
**Fermilab**
- For the** ****CDF and DØ**
**Higgs Sensitivity Group**
**Washington DC**
**June 19, 2003**

-  CDF’s set of flags (banner or individuals)

##  General comments
 The Strategy
 WH and ZH Analyses
 Combination of Channels
 Conclusions

** ****The Strategy**
** ****WH and ZH Analyses**
** ****Combination of Channels**
** ****Conclusions**

**Outline**

## The Run II Physics Program

** ****The Higgs search is very important**
** ****By no means this is the only thing we are (and plan on) doing**
** ****There is an extremely rich physics program - every time we double the integrated luminosity we open a new window (SUSY, LED, ...)**
** ****This is the frontier of HEP for the next decade or so**
** ****We should be taking advantage of this unique situation in every possible way – invest in accelerator/detectors**
** ****Fermilab and the two collaborations are committed to produce the most exciting physics on earth, if supported properly**

**Conclusion -  the Run II physics program at the frontier of HEP is very rich; let’s take full advantage of this unique opportunity**

## The Tevatron Experiments

** ****The experiments are up and running efficiently - we are collecting high-quality data at reasonable rates**
** ****All data are being processed by the reconstruction program “online”**
** ****Physics analyses are being performed in many areas**
** ****Re-establishing “old” measurements and limits**
** ****Testing the SM at a new/higher E****CM**
** ****New angles, new ideas,...**
** ****Looking for surprises – hints for physics beyond the SM**
** ****It’s very **
**  ****exciting!**

**Conclusion -  the experiments are running very well and producing world-class physics results (stay tuned for LP03,...)**

## Top Quark Search in Run I

** ****Prior to Run I (1992) theorists **
** ****and experimentalists estimated that:**
** ****Our sensitivity (mass reach) is**
**   ****going to be < 125 GeV**
** ****Our Tevatron mass resolution**
**   ****(uncertainty) will be ~13 GeV**
** ****The Top quark was discovered by**
**  ****CDF/****DØ in 1995**
** ****At a mass of 175 GeV !**
** ****Our current uncertainty on the **
**   ****top  mass is ~ 4 GeV !!**
** ****LEP had similar experience...**
** ****Other labs/experiments too...**

**Conclusion -  the sensitivity is always better than estimated prior to the Run**

## AnalysisStrategy

## We were asked by DOE about 6 months ago to provide a new estimate (plot?) for the Higgs sensitivity during Run II based on our current understanding of detectors and analysis components and their projected performance as luminosity becomes available
Timescale ~ June ’03 – very short!
What can we do?
No time for complete analysis!
Collaborations are extremely busy with Run IIa tasks
We’re all in this together...

- Timescale ~ June ’03 – very short!
- What can we do?
- No time for complete analysis!
- Collaborations are extremely busy with Run IIa tasks
- We’re all in this together...

**What? Why?**

## 
Form a CDF/DØ working group (minimal overlap with current mainstream efforts)
CDF Members: Kroll, Winer, (need all names here)+ Higgs group convenors + ...
DØ Members: Babukhadia, Fisher, Goussiou, Klima, Li, Narain, Partridge,  Rizatdinova, Tully, Turcot + Higgs group convenors + ...
Very few, very talented, very productive
Base on Run II Working Group study (hep-ph/0010338)
Split the work wherever possible, e.g. CDF - lbb, DØ - bb (the most sensitive modes), other decay channels?
Time permitted, add new channels, e.g W/Z (/H?) decaying to , H      WW, get smart in the analysis,...
Pleasant experience working together

- Form a CDF/DØ working group (minimal overlap with current mainstream efforts)
**CDF**** Members:** **Kroll, Winer, ****(need all names here)****+ ****Higgs group convenors + ...**
**DØ**** Members:** **Babukhadia, Fisher, Goussiou, Klima, Li, Narain, Partridge,  Rizatdinova, Tully, Turcot + Higgs group convenors + ...**
**Very few, very talented, very productive**
- Base on Run II Working Group study (hep-ph/0010338)
- Split the work wherever possible, e.g. CDF - ***l*******bb, DØ - ****bb (the most sensitive modes), other decay channels?
- Time permitted, add new channels, e.g W/Z (/H?) decaying to ******, **H      WW, get smart in the analysis,...
**Pleasant experience working together**

**Strategy ****(****CDF/****DØ**** ****)**

## IIa_LowL - used full GEANT simulation of the DØ detector for Run IIa (2E31), which reproduces most aspects of the current data (yes, we’re still fixing problems...)
IIa_HighL – same in high luminosity environment (2E32)
IIb_HighL – same using full GEANT simulation of the DØ detector (mainly new SMT for b tagging) for Run IIb in high luminosity environment (2E32)

Predicting future performance based on today’s best understanding of hardware and software
No time to fully optimise analyses or use relatively new analysis techniques – it will only get better

- IIa_HighL – same in high luminosity environment (2E32)
- IIb_HighL – same using full GEANT simulation of the DØ detector (mainly new SMT for b tagging) for Run IIb in high luminosity environment (2E32)
- Predicting future performance based on today’s best understanding of hardware and software
- No time to fully optimise analyses or use relatively new analysis techniques – it will only get better

**Tactics**

## Detailed studies on:
Triggers
B tagging
Di-jet mass
QCD background
WH and ZH analyses
Endgame
    are nicely documented – notes and presentations
See in
http://www-d0.fnal.gov/Run2Physics/higgs_sensitivity_study.html
    (Linked from our Physics main web page – in “News”)

**Triggers**
**B tagging**
**Di-jet mass**
**QCD background**
**WH and ZH analyses**
**Endgame**
-     are nicely documented – notes and presentations
- See in
- _[http://www-d0.](http://www-d0.fnal.gov/Run2Physics/higgs_sensitivity_study.html)__[fnal](http://www-d0.fnal.gov/Run2Physics/higgs_sensitivity_study.html)__[.](http://www-d0.fnal.gov/Run2Physics/higgs_sensitivity_study.html)__[gov](http://www-d0.fnal.gov/Run2Physics/higgs_sensitivity_study.html)__[/Run2Physics/](http://www-d0.fnal.gov/Run2Physics/higgs_sensitivity_study.html)__[higgs](http://www-d0.fnal.gov/Run2Physics/higgs_sensitivity_study.html)__[_sensitivity_study.html](http://www-d0.fnal.gov/Run2Physics/higgs_sensitivity_study.html)_
-     (Linked from our Physics main web page – in “News”)

**Documentation**

## Resultsfor WHlbb 

## Higgs Sensitivity Estimatein WHlbb 

-  Assume 100% QCD
-    contribution (a la SHWG)
-  NO trigger applied
-  35% b-tagging eff
- 1 tight + 1 loose tag
- 32% for 2 tight tags
-  Number of events
-    estimated in 1 fb-1

- ~50% less luminosity is needed compared to the 1999 study

- Direct comparison with the 1999 study

## WHlbb AnalysisUpdated Cross Sections

## Higgs Sensitivity Estimatefor WHlbb 

-  Trigger efficiencies
-  applied for this analysis
-  QCD as calculated in
-    current study
-  35% b-tagging eff
- 1 tight + 1 loose tag
- 32% for 2 tight tags
-  Number of events
-    estimated in 1 fb-1

- ~28% less luminosity is needed compared to the 1999 study

- Today’s results compared with 1999 study

## Higgs Sensitivity Estimate 

- Expected sensitivity in 1 fb-1

- ~20% less luminosity is needed compared to the 1999 study

- Today’s results compared with 1999 study

## Bad news
Our double b-tagging efficiency for Run IIa is currently estimated to be at X% compared to Y% using our IIb SMT – if we do not upgrade we’ll need more luminosity
Whatever bad happens to the detector, which is not currently being simulated...
Good news
Smart combination of results a la LEP (CLS vs straight counting) will buy us ~20% in luminosity
We have more new analysis techniques available today
Our analysis has not been optimised!

Looks promising...

**Our double b-tagging efficiency for Run IIa is currently estimated to be at X% compared to Y% using our IIb SMT – ****if we do not upgrade we’ll need more luminosity**
**Whatever bad happens to the detector, which is not currently being simulated...**
- Good news
**Smart combination of results a la LEP (CLS vs straight counting) will buy us ~20% in luminosity**
**We have more new analysis techniques available today**
**Our analysis has not been optimised!**
- Looks promising...

**Comments on ****WH*********l*********bb **

## Resultsfor ZHbb 

## Higgs Sensitivity Estimate for ZHbb  (Run IIb, L~2E32, mHiggs=115GeV)

-  Assume 100% QCD
-    contribution (a la SHWG)
-  NO trigger applied
-  35% b-tagging eff
- 1 tight + 1 loose tag
- 32% for 2 tight tags
-  Number of events
-    estimated in 1 fb-1

- ~50% less luminosity is needed compared to the 1999 study

- Direct comparison with the 1999 study

## ZHbb AnalysisUpdated Cross Sections

## Higgs Sensitivity Estimate for ZHbb(new x-secs, trigger eff., QCD)

-  Trigger efficiencies
-  applied for this analysis
-  QCD as calculated in
-    current study
-  35% b-tagging eff
- 1 tight + 1 loose tag
- 32% for 2 tight tags
-  Number of events
-    estimated in 1 fb-1

- ~28% less luminosity is needed compared to the 1999 study

- Today’s results compared with 1999 study

## Higgs Sensitivity Estimate  (Run IIb, function of mHiggs ) 

- Expected sensitivity in 1 fb-1

- ~20% less luminosity is needed compared to the 1999 study

- Today’s results compared with 1999 study

## Bad news
Our double b-tagging efficiency for Run IIa is currently estimated to be at 19% compared to 32% using our IIb SMT – if we do not upgrade we’ll need more luminosity
Whatever bad happens to the detector, which is not currently being simulated...
Good news
Smart combination of results a la LEP (CLS vs straight counting) will buy us ~20% in luminosity
We have more new analysis techniques available today, e.g. mtop
Our analysis is by no means fully optimised!

Looks good...

**Our double b-tagging efficiency for Run IIa is currently estimated to be at 19% compared to 32% using our IIb SMT – ****if we do not upgrade we’ll need more luminosity**
**Whatever bad happens to the detector, which is not currently being simulated...**
- Good news
**Smart combination of results a la LEP (CLS vs straight counting) will buy us ~20% in luminosity**
**We have more new analysis techniques available today, e.g. m****top**
**Our analysis is by no means fully optimised!**
- Looks good...

**Comments ****on  ZH********bb **

## Combined Resultsfor bb, llbb, and lbb

##            Higgs Sensitivity 

-   **Relative Contributions (a la LEP...)**

**ZH**

**WH**

## Higgs Sensitivity (bb + llbb + lbb ; CLS comb)

**Higgs Sensitivity ****(********bb + *****ll*****bb + *****l*********bb**** ****; CLS comb)**

-   **Combined ****DØ****/CDF**** Result**** **

- 5 discovery
- 3 evidence
- 95% CL exclusion

## Bad news?
We still have to work hard to get to the assumed/expected sensitivity (we will!)
We may be statistically unlucky...
Good news
We may be statistically lucky...
We know it will get better (tools, optimisation,...)
We expect it to get much better (remember Top in Run I!)

Great Start...

- We still have to work hard to get to the assumed/expected sensitivity (we will!)
- We may be statistically unlucky...
- Good news
- We may be statistically lucky...
- We know it will get better (tools, optimisation,...)
- We expect it to get much better (remember Top in Run I!)
**Great Start...**

**More Comments**

## We are excited to work at HEP’s frontier program
Both collaborations are committed to producing exciting physics until the end of the decade
The experiments are running very well and producing world-class physics results
This study proved that the Higgs reach at the Tevatron is at least as good as projected 4 years ago
The Higgs sensitivity will improve over time as we get more data, better understand our detectors, use smart analysis techniques, and develop new ideas
We are looking forward to a long and exciting Physics program at the world’s frontier energy

**Both collaborations are committed to producing exciting physics until the end of the decade**
**The experiments are running very well and producing world-class physics results**
**This study proved that the Higgs reach at the Tevatron is at least as good as projected 4 years ago**
**The Higgs sensitivity will improve over time as we get more data, better understand our detectors, use smart analysis techniques, and develop new ideas**
**We are looking forward to a long and exciting Physics program at the world’s frontier energy**

**Conclusions**