# Presentation: 191822

## Fermiophobic Higgs

- Drew Baden
- University of Maryland
- Dzero Collaboration
- EPS 2003

## Fermilab Tevatron

**Run ****I**** 1992-96**
**about 100 pb****-1**** recorded**
**1.8TeV cm energy**
**3.6********s bunch crossing**
**MainRing**
**Synchrotron injector for Tevatron**
**In same tunnel ******
**Run ****II**** 2001-...**
**1.96TeV cm energy**
**396ns bunch crossing**
**MainRing pulled, Main Injector built**
**$230M project**

## D Detector

**Upgrades:**
**2T Solenoid**
**>100k scint. fibers**
**>700k silicon strips**
**Muon detector improvements**
**Preshower added**
**CAL, Muon, trigger electronics**
**NO MAIN RING!!!**

**Silicon tracking out to ********~2**

**Yields**

## Run 2 Data Taking

- Delivered

- for Physics

## Higgs – Current Understanding

- Discovery motivation is obvious
- Higgs is a central part of the Standard Model
- But after discovery, the Higgs mass must be determined
- MHIGGS determines decay , and production for coupling to all particles
- Constraints on MHIGGS

- LEP direct search
- M>114GeV @ 95% CL

- ElectroWeakWorkingGroup
- Favors light higgs, 91GeV central value
- M<211 GeV 1-sided 95%CL

## What is Fermiophobic Higgs?

- Fermiophobic...means you turn off couplings to fermions
- Can occur in Type-1 2-doublet Higgs models
- Type-1 – one doublet couples to fermions, the other to bosons
- CP even neutral Higgs bosons, light h and heavy H
- scalar field mixing angle 
- coupling to fermions via
- mass, as usual, and
- sin() for H and cos() for h
- h is therefore “fermiophobic” in the limit →/2
- Of course we could have a “fermiophobic” H (→0)...but h is lighter so we look there...

## Fermiophobic Higgs Production

- Effect on Higgs production:
- Eliminates gluon fusion
- Biggest contribution to SM Higgs production... 
- Leaving:
- “Associated Production”
- Virtual W*/Z* → onshell W/Z+h
- WW fusion
- Quark lines radiate W’s, fuse to h
- ZZ fusion too small by usual EWK factor

## Fermiophobic Higgs Decay

**Fermiophobic Higgs Decay**

- Final states:
- No bb in the final state (fermiophobic!)
-  
- Through W triangle loop
- Dominates at low Mh
- Also WWvertex
- Suppressed by ~1/137
- Associated Production:
- Z/W+h where h → WW/ZZ
- But h →ZZ suppressed
- Dominant final states are
- ZWW,  WWW
- Physics background from ZWW, standard EWK tri-linear coupling
- h → WW dominates at high Mh
- LEP Combined Fermiophobic limit
- Mh < 108.2 GeV @ 95% CL using h →  mode

**M****H****< 114.4**
**EWWG**

**LEP  Higgs Working Group benchmark model**

**SM Branching Fractions**

**M****h****< 108.2 **
**LHWG Note 2001-8**
**Hep-ex (0107035) 2001**

## Experimental Limits

- LEP Combined Fermiophobic limit
- Mh < 108.2 GeV @ 95% CL using h →  mode
- LHWG Note 2001-8 and Hep-ex (0107035) 2001
- D/CDF Run1 limit 78.5 / 82.0 GeV at 95% CL
*B.Abbott et al. Phys. Rev. Lett. ****82****, 2244 (1999 )*
*F.Abe et al. Phys. Rev. ****D59****, 092002 (1999) LEP*** **

## This Talk....

- So, for this talk, present status on:
- W*/Z* → W/Z h, h → WW
- Look for the h → WW
- Focus on final states with 2 W’s
- 2 Z’s will be relatively suppressed (see previous slide)
- Search for inclusive ee, ,  and e± lepton pairs + MET
- The “prompt” W/Z in final state...
- No requirement on any leptonic decay
- W/Z*h → W/Z
- Look for states with 2s
- large MET and/or jets
- Let the theorists foot the bill as to interpretation
- Which particular “Type” etc.

## H → WW → ll

- Data:
- Dielectron sample:  44pb-1
- e sample:  34p-1
- Backgrounds
- ee Dominated by Z → ee
- Reduced via MET cut
- Some ’s remain
- All dilepton channels have
- WW/Wg/ZZ/WZ
- top
- W+jet and QCD misidentification

## Electron ID

- Electron ID requirements
- Triggered
- Isolation+EMF+Shower Shape
-   = 85% (93%) efficiency for central (endcap)
- Track match via 2(E/p and ) and DCA
-   =73% obtained using sample of Z → ee
- Leading electron PT>20 GeV, 2nd electron PT>10 GeV
- Reduces multijet background

## Muon ID, Jets, and MET

- Muons:
- Isolated from jets
- Calorimeter energy:  E(R<0.4) - E(R<0.1)<2.5GeV
-  PT (in cone R<0.5) tracks < 2.5 GeV
- Reject cosmics via timing requirement
- PT > 10 GeV
- Central track match
- Jets:
- Cut to eliminate hot towers, other pathologies
- EMF cut
- ||<2.5
- Energy corrections, cone 0.5
- MET
- Use calorimeter cells
- Correct for jet energy corrections
- Use 0.7cone jets for this

## Event Cuts

- Electrons
- 2 with PT> 20 GeV
- at leats 1 with track match
- M(ee) < 78 GeV to reject Z’s
- MET
- MET > 25 GeV and (jets,MET) > 0.5
- Dominant background is W+jets
- Spin Correlations
- W and W  have opposite spin projections
- Tendency for charged leptons to be emitted along same direction
- Require (leptons)<2.0

- (**l********l******)

**Higgs**

**WW**

**Top**

**QCD**

**Z****→****ee**

**Z****→******

**W+jets**

**W+******

## ee Final State

- Dominant background from Z → ee
- Invariant mass cut M(e+e-)<MH/2 for limit calculation
- 96% effecienty for MH=160GeV
- Further MET cuts to reduce jet-induced MET
- Transverse mass cut MT<MH+20 GeV
- Both electrons have PT>20 GeV

**M(e********e********) before cuts**

**M(****e********e********) after electron selection and PT cut**

## ee Result

- Data after all cuts...
- Monte Carlo
- Pythia 6.202 + full sim/reconst.
- 0.5min bias overlay
- Multijet backgrounds from data
- Require poor electron, study...
- Higgs signal
- Efficiency vs. MH
- Backgrounds vs. Data
- largest uncertainty is in W+jets and Z(ee)

| MH(GeV) | 120 | 140 | 160 | 180 |
| --- | --- | --- | --- | --- |
| ID, pt>20 | 2753 | 2753 | 2753 | 2753 |
| M(e+e-)<MH/2 | 262 | 378 | 598 | 1617 |
| MET > 20 | 11 | 27 | 37 | 52 |
| More MET cuts | 1 | 16 | 25 | 38 |
| Df(ee)<2.0 | 0 | 2 | 2 | 4 |

******(ee) MC/Data Comparison**

| 120 | 140 | 160 | 180 |
| --- | --- | --- | --- |
| 8.1 ± 0.4% | 10.6 ± 0.4% | 16.2 ± 0.5% | 14.4 ± 0.5% |

|  | TOP | WW | W+ | W+jet | Z() | Z(ee) | QCD | SUM | Data |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 120 | 0.10 | 0.13 | 0 | 0 ± 1.1 | 0 | 0 ± 0.9 | 0.7 | 0.7±1.4 | 0 |
| 140 | 0.08 | 0.21 | 0 | 0 ± 1.1 | 0 | 0 ± 0.9 | 0.7 | 1.0±1.4 | 2 |
| 160 | 0.07 | 0.27 | 0.01 | 0 ± 1.1 | 0 | 0 ± 0.9 | 0.7 | 1.3±1.4 | 2 |
| 180 | 0.08 | 0.27 | 0.02 | 0 ± 1.1 | 0 | 0 ± 0.9 | 1.4 | 2.6±1.4 | 4 |

**Selection optimized for MH=160**

## e± Final State and Results

**e************±**** Final State and Results**

- Comparison with e+e- analysis
- No Z decay background
- No transverse mass cut applied
- MET cut constant:  MET > 20 GeV
- Less QCD multi-jet background
- MET and PT() not aligned
- All other cuts are the same
- Efficiencies:
- Backgrounds mostly W+jets
- Results combing ee and e±
- Upper limit of 2-3pb @ 95%CL
- Limited data...x4 being analyzed now
- Need ~10fb-1 to be sensitive up to Mhiggs=160 GeV

| M Higgs | 120 | 140 | 160 | 180 |
| --- | --- | --- | --- | --- |
| Efficiency | 4.5 ± 0.3% | 8.6 ± 0.4% | 11.7 ± 0.5% | 10.9 ± 0.5% |

|  | TOP | WW | W+ | W+jet | Z() | QCD | SUM | Data |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 160 | 0.13 | 0.18 | 0.06 | 0 ± 1.5 | 0 | 0.4 | 0.9± 1.5 | 1 |

******Br(H ****→****WW → e****+****e****-****/ e************±**** )**

##  Final State

- 48pb-1 analyzed
- 2 High PT isolated muons (||<2)
- Same cuts as previous
- M(), PT(), MET, (MET,jet),MT, ()
- MC samples from Pythia 6.202, full sim/reconst
- Same as for previous study
- QCD and W+jets backgrounds from data
- using muon isolation
- Normalized to Z→ 
- Overall signal efficiency for Mh=160 GeV is 14.6 ± 0.6%

##  Result

- 1 Event remains
- 48pb-1 data
- 14.4% overall efficiency for 160 GeV Higgs
- 0.32 ± 0.01 expected from backgrounds
- No official upper limit on Br yet...
- Will be reporting combined H → WW →  ee, ,  and e± on 120pb-1 very soon

|  | TOP | Z() | WW | W+jet | Z() | QCD | SUM | Data |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Events | 0.11 | 0 | 0.20± 0.01 | 0  | 0 | 0 | 0.32±0.01 | 1 |

## H → + X

- 52pb-1 analyzed
- Topcolor model also considered
- Fermiophobic except for top
- Photon id:
- EMfraction>0.9 , Shower shape 2, isolation, PT>25 GeV, charged track veto
- “Fake” photons due to
- high PT 0→   (small opening angle)
- Drell-Yan + tracking inefficiency
- jet fluctuations mimic photon (high EMfraction)
- non-prompt QCD photons QCD

## H → + X Result

- Interesting to also consider TOPCOLOR
- Technicolor extension, fermiophobic except for top quark loops
- Assume Br(h → ) = 1
- Starts to get interesting at 120 GeV!

## Tevatron Higgs Working Group 

- Discovery at 3-5 can be made
- Combine all channels, data from
-      both D0 and CDF
- Improve understanding of signal
-     and background processes
- b-tagging, resolution of Mbb
- Advanced analysis techniques are vital
- Largest luminosity required to discover Higgs
- Results of simulations consistent with SHWG expectations

**Tevatron Higgs Working Group **