# Presentation: 647090

##        CDF	Searches Overview

- Tracey Pratt
- Liverpool University

-  Extra Dimensional Models and their Signatures
-  Introduction to the Tevatron and CDF
-  Search channels, Search Strategy
-  Comparison of Background Expectation to Data
-  Preliminary Results
-  Conclusion and Outlook

- Extra Dimension

- * searches presented by A. Anastassov

- I’ll breifly introduce the

## Extra Dimensional Solutions the Hierarchy Problem

- for n  2, Rc < 1 mm

- Vn = 2Rcn

-  requires Rc ~ 10(30/n –19) m

- Torus

- Curvature of the extra dimension

-  Gravity localised in the ED

- Scale of physical phenomena on the TeV-brane is specified by the exponential warp factor:
- 	= MPle-kRc
-      ~ TeV if kRc ~11-12.

- Planck	        TeV brane

- RS

- 1 highly curved extra dimension

**Extra Dimensional Solutions the Hierarchy Problem**
**   ****(M****EW**** << M****Pl****anck****?) **

- hep-ph 9905221

- hep-ph 9803315

- Potentially experimentally detectable at detectors ...

## Experimental Signatures for

- Two classes of experimental tests
- Graviton emission
- 		and a photon or a jet recoiling against it,
- 		Gravitons, do not interact with the detector, and radiate into the bulk appearing as missing energy:
- 	jet + ET		 + ET
- Cross section depends on the number of extra dimensions
- 2.   Graviton exchange
-    	 Deviations in the cross section from SM predictions

- _New Parameters  _(Hewett formalism)
- Ms ,(MD = MPl(4+n))
- , dimensionless parameter, 1

- Since gravitons can propagate in the bulk, energy and momentum are not conserved in the GKK emission from the point of view of our 3+1 space-time
- Since the spin 2 graviton in generally a has a bulk momentum component , its spin from the point of view of our brane can appear as 0, 1 or 2

- Gravitons, do not interact with the detector, and          radiate into the bulk, appearing as missing energy (MET):
-             jet + MET		         + MET
- Cross section depends on the number of ED

- the collider signatures include single photons/Z/jets with missing ET or fermion/vector boson pair production

- ADD

- probe Kaluza-Klein gravitons (GKK) by:

- Picture of cross-section for emission

- Run I

-    M (GeV)

**2)** **Graviton exchange****:** virtual contribution to the scattering processes
-       Deviations in cross sections and asymmetries of SM processes
-        	e.g.	qq-bar  l+l-,  
-       	Or new processes e.g. gg  l+l-,
-       Cross section independent of the number of ED
-       in Hewett formalism

- Gupta et. al. hep-ph/9904234

- s is the Planck scale in the extra dimensions
-  is a dimensionless parameter of order  1

- =+1

- _New Parameter_
- Fundamental mass scale MD   GN-1 = 8RnM2+nD ,
- where GN-1 Newton’s constant

- _New Parameter_
- Fundamental mass scale MD and R are related to Newton’s constant GN-1  and the number of extra dimensions by GN-1 = 8RnM2+nD

**1)** **Direct G****KK ****emission** in association with a vector-boson

## Experimental Signatures for            ED

- RS

- (Add BRs here?!)

- (Why not diphoton ?!!)

- K/MPl

- 6

- 700 GeV KK Graviton at the Tevatron
- k/MPl = 1,0.7,0.5,0.3,0.2,0.1 from
- top to bottom

-    Mll (GeV)

- RS model

- Dilepton channel

-               400  600  800 1000

- Mll (GeV)

- 10-2
- 10-4
- 10–6
- 10-8

- 10-2
- 10-4
- 10-6
- 10-8
- 10-10

- Tevatron 700 GeV KK graviton

- d/dM (pb/GeV)

- Massive eigenstates only suppressed by -1 ~ TeV-1
- RS modes can be excited individually on resonance

- Via Virtual exchange
-         but different expected cross sections/distributions from ADD model

**Via virtual exchange**

- Davoudiasl, Hewett, Rizzo hep-ph0006041

-      1000     3000     5000

- 1
- 0.5
- 0.1
- 0.05
- 0.01

- 1
- 0.7
- 0.5
- 0.3
- 0.2
- 0.1

- KK excitations can be excited individually on resonance

- The cleanest signature for graviton resonance production is an excess of events in the dilepton or dijet channel.

- 1500 GeV GKK                          and subsequent tower states

- K/MPl

-  LHC

-  BR(**G→******) =  2 * BR(**G→ee**)

## CDF @ Tevatron pp Collider 

**CDF @ Tevatron**** p****p**** ****Collider **

***Highest energy collider operating in the world!***

- and ability to set improved limits on new physics

- D0

**p**

**p**

- CDF

- Run II  (2001-2009)
- √s  1.96 TeV
- Physics Analyses use ~ 200/pb collected between 03/02 and 09/03
- diphoton search 300/pb

- Ldelivered ~400/pb

- Run I  (1992-1996)
- √s  1.8 TeV, 110/pb

**Delivered**
** ****To Tape**

- Run I  (1992-1996)
- √s  1.8 TeV, 110/pb
- Run II  (2001-2009)
- √s  1.96 TeV
- Physics Analyses use ~ 200/pb collected between 03/02 and 09/03
- diphoton search 300/pb

## CDF ED Search Channels

*Channel    Run I      Run II*
*Emission** *
-  + MET         	         
- jet+ MET            	         
*Virtual Graviton Exchange*
*ee**	**        *          
-           
- *ee **	**        *          

- ADD

- RS

*ee**	**	**        * 
-  
*ee* + 
- 
- jet-jet                          
- ZZ 		         

- (top pair,

*being updated*

- for completeness I’ll summarise the Run I results too: to show all CDF ED results – breifly and point out improvements being made for Run II – I’ll concentrate on Run II results

*Channel    Run I      Run II*
*Virtual Graviton Exchange*

* * Completed
-   On their way!

## Run I GKK emission: Et

- Run I GKK emission: Et

- CDF 5725

**Limits**
- n=4  MD > 0.55 TeV
- n=6  MD > 0.58 TeV
- n=8  MD > 0.60 TeV

- The fundamental mass scale MD and R are related to Newton’s constant GN-1  and the number of extra dimensions by GN-1 = 8RnM2+nD

- No signal is observed

- L3 has set limit MS >1 TeV for n=2 (hep-ph0003306)

**Search Selection **
-  - One  with ET > 55 GeV and ||<1
-  - Missing ET > 45 GeV
-  - No jets with ET > 15 GeV
-  - No tracks with pT > 5 GeV

**Main backgrounds**
- Cosmic rays where muon undergoes a Bremsstrahlung in the calorimeter
- Irreducible Z +
- We (), W (),  (),jet-jet, -jet (+MEt)

**Results**
- Expected background: 11.0  2.3
- Observed: 	        11

- irreducible

- 95 % C.L. ADD limits:
- GN-1 = 8RnM2+nD
- MD = 549, 581, 602 GeV
- 	n=4,6,8 extra dimensions

**but no track is found**

- Other backgrounds:
- W->e nu, where the e is misidentified as a photon
- W -> where the charged lepton in a leptonic W decay is lost
- Prompt photon-photon production where a photon is lost
- Dijet
- Photon+jet production

- CR cuts are timing cuts
- (No jets with ET > 15 GeV and No tracks with pT > 5 GeV) are to remove backgds from W and events in which mismeasurement of jet energy produces fake MEt

- Events surviving cuts
- 15,046
- 1,475
- 94
- 11

- PRD

| Cosmic ray muons | 6.3  2.0 |
| --- | --- |
| Z0+ | 3.2  1.0 |
| W e (““) | 0.9  0.1 |
| Prompt diphotons | 0.4  0.1 |
| W ()  | 0.3  0.1 |

**Main backgrounds**

- 87 pb-1

- Numbers don’t add due to rounding

- Limiting factor was high ET threshold –                   	   New in Run II.....

## Real GKK emission : jets+Et

- CDF 5151

- Dashed lines for  from Pythia
- Solid lines prediction from Giudice, Rattazi and Wells (hep-ph9811291)

-  falls as 1/MDn+2 for all subprocesses

- qq-bar  gG is larger for larger values of n, relative to the other sub-processes,
- since (gggG) and (qggG)
- depend on (m2/s)4
- Whereas (qq-bargG)  depends on (m2/s)3
- This results in larger splittings at high values of MD between values of n for qg and gggG compared to qq-bargG.

- For n=2 qq-bar is not the dominate process, but for n>2 then this is the dominate process

| Process
MD = 1 TeV | n(pb)
Total) | n(pb)
Total) | n(pb)
Total) |
| --- | --- | --- | --- |
| qq-bargGKK | 4.1 
(0.16) | 1.6
(0.53) | 0.70
(0.78) |
| qggGKK | 9.6
(0.38) | 0.68
(0.22) | 0.096
(0.11) |
| qggGKK | 11.4
(0.45) | 0.77
(0.25) | 0.11
(0.12) |
| Total | 25.2 | 3.05 | 0.90 |

- Tevatron s=2 TeV MD = 1.2 TeV

- n=4

- n=2

- pTmin (GeV)

## Run Ib GKK emission: jets+ET

- CDF 5151

- The fundamental mass scale MD and R are related to Newton’s constant GN-1  and the number of extra dimensions by GN-1 = 8RnM2+nD

- Compare to LEP and Delphi results?- in the paper (for that time)

**Search Selection**
-     Jet ET1st 80 GeV, || <1.1 and ET>80 GeV
-     a second jet is allowed if ET2nd > 30 GeV
-     no isolated tracks in event (pT10 GeV)
**Main background** Z()+jets, W()+jets.

- L3 gives limit Ms > 600 GeV hepph0003306

- pp  jet +MEt subprocesses:
- qggG, qq-bargG and gggG.
- Main bkgd from Z+jet +jet
- LHC: qggG gives largest contribution

|  | Run I : MD (TeV) > |  |  |
| --- | --- | --- | --- |
| n | CDF(K=1.0) | D0(K=1.0) | D0(K=1.34) |
| 4 | 0.77 | 0.66 | 0.73 |
| 6 | 0.71 | 0.63 | 0.65 |

***CDF Run I : Best limits from the Tevatron from searches for direct graviton emission***

- Run Ib GKK emission: jets+ET

**Results**
- Expected: 27416  Observed: 284 events.
- Relative uncertainty on the signal acceptance 25 %

**Limits**
- 95 % C.L. upper limit on number of signal events: 62

- 84  4 pb-1

- Used Poilim (poisson statistics) 

- Normalise bkgd predictions to Zee+jets data and use direct normalisation of W->enu+jets as a cross check

- Allowing a 2nd jet: improves the signal eff. (2nd jet from ISR or FSR) And allows us to estimate the QCD bkgd using data.
- No tracks; reduces bkgd from W+jets

***Run II CDF search underway!***

| 2 | 995 | 886 | 987 |
| --- | --- | --- | --- |

| Run II 85pb-1 |
| --- |
| D0(K=1.3) |
| 0.68 |
| 0.66 |

## Search for ED via Virtual Graviton Exhange

- l+

- l-

- q

- q

- /Z

**Search for ED ****via Virtual Graviton Exhange**

- Deviations in cross sections () and angular distributions                    from SM processes caused by graviton exchange
- Broad change in  in ADD model and resonance in RS model

- Clean experimental signature
**Also search for other physics models: spin-0;1;2: R****P********;Z****‘,Z****H****;G****,**

- Diphoton Channel

- gg initiated process

- Dilepton Channel

- Extra Dimensions

- q

- q

- gg initiated process

- Low backgrounds

- Standard Model

- l-

*Z*/

**~**

## ADD dielectron search

**ee**
- 2 two isolated e, ET > 25 GeV
- 2 central e (CC)
- or 1 central and 1 forward e (CP)

- Perform searches compare to bkdgs and apply to new physics models

- COT

-       Plug Calorimeter

- Time-of-Flight

-     Central Calorimeters

- Solenoid

- Silicon Tracker

- || < 1

- 1<||<3

| Mass 
(GeV/c2) | Nexp | Nobs |
| --- | --- | --- |
| 200 | 70.5 | 71 |
| 300 | 11.1 | 14 |
| 350 | 4.6 | 9 |
| 400 | 2.0 | 2 |
| 450 | 0.9 | 0 |

- CC+CP

*Good agreement with SM prediction*

## ADD dielectron search

- 		 Set a limit on the effective Planck scale (Ms4)
- 		        using invariant mass spectrum (1D fit)

- Gupta et. al. hep-ph/9904234

- Parameterise the cross section in terms of =/ s4 (=±1)        **** =   ******SM** + ******INT **+ 2 ******KK**

- A 3 parameter (nSM, nBG, ) unbinned likelihood function is used to extract 

- Generate MC templates for each piece independent of the choice of  and s4.

- D0 1.28 GeV (GRW) 128 pb-1 ee/

- ee

- CDF Run I: 780 768

**987  959**

- systematics /efficiencies?

- Same as D0 dielectron limits – but their diEM better

## Angular Distributions

- can I say that these are ... - what deviations would we expect though?!

- Results consistent with the background

- cos* in Collins-Soper frame

**ee**

- 1-D fits performed, but also study angular distributions

***Good agreement with SM prediction***

## RS G Exchange Search Selection

***ee***** – use the same sample **
**        ****as for the ADD search**
- 2 two isolated e, ET > 25 GeV
- 2 central e (CC)
- or 1 central and 1 forward e (CP)

****
- 2 isolated  PT>20 GeV
- |1|<1, |2|<1.5
- Cosmic ray rejection cuts

****
- 2 isolated  ET>15 GeV
- 2 central   (CC)

- Perform searches compare to bkdgs and apply to new physics models

- Muon System

- COT

-       Plug Calorimeter

- Time-of-Flight

-     Central Calorimeters

- Solenoid

- Silicon Tracker

- || < 1

- 1<||<3

- || < 1.5

- || < 1

***jet+jet***
- 2 isolated  ET>15 GeV
- 2 central   (CC)

##  High Mass Dimuons

***High mass dilepton spectra is consistent with background prediction***

| Mass 
(GeV/c2) | Nexp | Nobs |
| --- | --- | --- |
| 150 | 55.25 ± 2.50 | 58 |
| 200 | 20.88 ± 0.97 | 18 |
| 250 | 9.44 ± 0.49 | 9 |
| 300 | 5.22 ± 0.32 | 6 |
| 350 | 3.23 ± 0.24 | 1 |
| 400 | 2.28 ± 0.19 | 1 |
| 450 | 1.79 ± 0.16 | 1 |
| 500 | 1.24 ± 0.13 | 1 |
| 550 | 1.03 ± 0.11 | 0 |

**Total of ~ 7500 dimuon candidates in 200 pb****-1**** data**

## High Mass Diphotons

**Search selection**
- 	2 isolated  ET>15 GeV, ||<1

**Backgrounds**
-    Standard Model diphoton production
-    Fakes: -jet and jet-jet,
-      where jet fragments into a hard 0

**405 GeV/c****2**

- Add table for expected high mass?

##  Highest Mass Event

## Spin-dependent Acceptance

- The following plots show the efficiency times acceptance of detecting a particle decaying into a electron-positron pair as function of the mass. Since the spin of the particle changes the angular distribution of the decay particles we consider the possible spin of any new particle separately: spin-0 , spin-1 and spin-2.

- Angular distribution and therefore acceptance of decay products         depends on the spin of the decaying particle.
- Determined using Monte-Carlo

## New Physics Limits

- 95 % C.L. upper limits on .BR(*X*→*ll*) for spin-0,1,2 and lower limits
- on string scale are placed using binned likelihood method

- ni : observed events
- i= Nisig + Nibkg (Resonant particles)
- i= Nisig() + Nibkg (LED spectrum)

- Likelihoods are integrated to give the final limits, taking into account the signal and background systematic uncertainties

- 1 and 2  error

- spin-1

- detector description,..)

- _Sources of systematic uncertainties:_
- Luminosity (6%)
- Acceptance (PDF, MC statistics..)
- Energy/Momentum scale resolution
- Selection Efficiencies
- Background statistics and normalisation

- 1 and 2  error on the expected limit

- 1sigma error and
- 2 sigma error on the expected limit

- spin-1

-  Observed limit consistent with expectation
-  Applicable to any new possible future theory

- Repeat the pseduoexperiment 1000 times. The value of each bin is chosen randomly from Poisson distribution which has the mean value of the expected background.

- 95 % CL upper limits on sigma*BR for spin-0,1,2 used to set limits (all except LED – limit set using binned likelhood method)

- 95 % C.L. upper limits on .BR(G→) are placed using ± 3 search windows around MG

- Bayesian method with flat prior probability

- 1) Scan through , and at each point, reminimise L w.r.t nSM and nBG.
- 2) Plot L
- 3) 95 % C.L. result is the value of  such that 95 % of area under the likelihood function lies between it and 0.

- N95%=95%Nsig

## Run II dijet search at CDF

**Run II dijet search at CDF**

- Inclusive Jet samples
- 2 highest ET jets selected

*RS model dijet limits to be determined.*

**Highest mass event ****1364 GeV/c****2**

- ET=666 GeV (corr)
-  583 GeV (raw)
- =0.31 (detector)
- =0.43 (correct z)

-  ET=633 GeV (corr)
- 546 GeV (raw)
- =-0.30 (detector)
- =-0.19 (correct z)

- z vertex = - 25 cm

- J1 ET = 666 GeV (corr)
-  583 GeV (raw)
- J1  = 0.31 (detector)
- = 0.43 (correct z)

- J2 ET = 633 GeV (corr)
- 546 GeV (raw)
- J2  = -0.30 (detector)
- = -0.19 (correct z)

- z

- 

- CDF6248

- MET/ET<6 and E<2.2 TeV

- include color octet technirhos, W' and Z'.
- Randall-Sundrum Gravitons were approved.
- log scale plot comparing run 1 and run 2 data with 139 pb^-1
- The run 2 dijet mass spectrum (_[ ](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMass.eps)__[eps](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMass.eps)_,_[ ](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMass.ps)__[ps](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMass.ps)_,_[ gif](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMass.gif)_) begins at 180 GeV and falls steeply.
- The highest mass event (_[ ](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/r152507_e1222318.pdf)__[pdf](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/r152507_e1222318.pdf)_,_[ ](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/r152507_e1222318.ppt)__[ppt](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/r152507_e1222318.ppt)_) has a dijet mass of 1364 GeV.
- Comparing the spectrum in run 1 and run 2 on a log scale (_[ ](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMassComp.eps)__[eps](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMassComp.eps)_,_[ ](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMassComp.ps)__[ps](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMassComp.ps)_,_[ gif](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMassComp.gif)_) we see that the run 2 cross section at sqrt(s)=1.96 TeV is everywhere above the run 1 spectrum at sqrt(s)=1.80 TeV. The log scale comparison is also available for 139 pb^-1 of run 2 data (_[ ](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMassComp139.eps)__[eps](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMassComp139.eps)_,_[ps](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMassComp139.ps)_,_[ gif](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMassComp139.gif)_); this is the only result currently available for more than 75 p^-1 of run 2 data. The ratio of the cross section in run 2 to that in run 1 (_[ ](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMassRatio2.eps)__[eps](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMassRatio2.eps)_,_[ ](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMassRatio2.ps)__[ps](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMassRatio2.ps)_,_[ gif](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMassRatio2.gif)_) compares favorably with a lowest order parton level calculation. From the same plot with an expanded scale (_[ ](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMassRatio.eps)__[eps](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMassRatio.eps)_,_[ ](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMassRatio.ps)__[ps](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMassRatio.ps)_,_[ gif](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMassRatio.gif)_) we see the cross section for the highest mass dijet events is up to 10 times higher in run 2 than in run 1.

## Dijet Limits 75pb-1

- The fit on a log scale (_[ ](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMassFit.eps)__[eps](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMassFit.eps)_,_[ ](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMassFit.ps)__[ps](http://www-cdf.fnal.gov/physics/exotic/run2/highmass-jets-2003/DijetMassFit.ps)_, gif), the fractional difference between the data and the fit ( eps, ps, gif), and the statistical residuals between the data and the fit ( eps, ps, gif), show there is no significant evidence for a new particle signal.

- Fit the mass spectrum with a simple background parameterization and
- Search for bumps comparable with our mass resolution.

***No significant evidence for a new particle***

## CDF RS Graviton Limits

- Scale of physical phenomena on the TeV-brane is specified by the exponential warp factor:
-            = Mple-kRc
-      ~ TeV if kRc ~11-12.

- Randall-Sundrum gravitons are excluded by these data in the plane of coupling (k/MPl) versus effective graviton mass. E.g. for k/M_Pl=0.05 masses less than 500 GeV are ruled out at 95% C.L..

- for k/M_Pl=0.05 masses less than 500 GeV
- are ruled out at 95% C.L..

- Scale of physical phenomena on the TeV-brane is specified by the exponential warp factor:
-            = Mple-kRc

-  ~ TeV if kRc ~11-12.

- 470 **GeV/c****2**

- Clean experimental signature. Low backgrounds

- gg initiated process

- Dilepton Channel

*ee*

****

- 620 **GeV/c****2**

- K/Mpl 0.1	620
- 	0.05	470
- 	0.02	310
- 	0.01	200

- Add Run I limits?!

-  **ee** has largest acceptance at low mass
**  ******** **has largest acceptance at high mass
-  BR(**G****→******) =  2 * BR(**G→ee**)

****

| Channel | Luminosity
(pb-1) | MG(GeV/c2)
K/MPl=0.01 | MG(GeV/c2)
K/MPl=0.1 |
| --- | --- | --- | --- |
| ee | 200 | 200 | 640 |
|  | 200 | 170 | 610 |
| ee+ | 200 | 200 | 700 |
|  | 345 | 220 | 690 |

-  BR(**G→******) =  2 * BR(**G→ee**)

*jetjet   *75pb-1 exclude 220-840 GeV: k/MPl=0.3

## Angular Distributions

**Angular Distributions**

****

- can I say that these are ... - what deviations would we expect though?!

- Results consistent with the background

- cos* in Collins-Soper frame

- Not used in limits – but still studied

****

## Conclusions and Outlook

-  Searches for ED have been performed in many channels at CDF
-  No evidence of deviations from Standard Model expectation observed
-  Best limits obtained
- ADD   jets+ET, ee +   ~ 1 TeV
- RS     (345pb-1)m1 ~ 220 to 690 GeV for k/MPl 0.01 to 0.1
-           *ee* +    (200pb-1) m1 ~ 200 to 700 GeV for k/MPl 0.01 to 0.1
-  Many new results and publications on their way....
-       *ee* PP search
-       *ZZ* channel
-  Tevatron Run IIa (2 fb-1) has a promising observation potential  	             and should be in a position to discover ED, if they exist,
-              ADD: up to about MS = 2 TeV
-              RS: m1 from 0.5 to1 TeV for k/MPl 0.01 to 0.1

- The highest limits obtained are from the ** channel.

-  Many interesting channels to look in.
-  Run II results already coming in
-  To be updated in the future...

- ADD ee +     939 (853)  GeV for =-1 (+1), KLED = 1.3
- 	 ADD jets+ET    995 for n=2, 768 for n=4
-         RS   ee            205 to 535 GeV for k/MPl 0.025 to 0.1

- Tevatron Run II has a promising observation potential  	              	and should be in a position to discover ED, if they exist,
- ADD: up to about MS = 2 to 3 TeV (Runs IIa, 2 fb-1; IIb, 20 fb-1)
-       RS: m1 from 0.5 to 1 TeV for k/MPl 0.01 to 0.1 (Run IIa, 2 fb-1)

**Look out for CDF results!**

## High Mass Dielectrons 

**High Mass Dielectrons**

- CDF6343

- We find good agreement with the Standard Model expectation
- and thus set an upper limit on the production cross section (times branching ratio)
- for the production of particles leading to this signature.
- We do this separately for spin-0, spin-1 and spin-2 particles
- since the experimental acceptance depends on the spin. We then interpret this cross section limit
- in terms of physics beyond the Standard Model:
- Z', RS Gravitons, sneutrino, technicolor, Little Higgs.

- The main source of background is Drell-Yan. Jets being misidentified as electrons (labelled "QCD") are another important source of background.

- 371 GeV

- PP

- Typical  CC event

- PP

| Mass 
(GeV/c2) | Nexp | Nobs |
| --- | --- | --- |
| 200 | 10.2 +/- 2.2 | 14 |
| 300 | 2.5 +/- 0.7 | 8 |
| 350 | 1.4 +/- 0.33 | 3 |
| 400 | 0.71 +/- 0.17 | 2 |
| 550 | 0.1+/-0.03 | 0 |

*Good agreement with SM prediction*

- COT

-       Plug Calorimeter

- Time-of-Flight

-     Central Calorimeters

- Solenoid

- Silicon Tracker

- || < 1

- 1<||<3

- Using Plug-Plug electrons too

***ED limits presently being set!***

## Conclusions and Outlook

-  Searches for ED have been performed in many channels at CDF
-  No evidence of deviations from Standard Model expectation observed
-  Best limits obtained
- ADD   jets+ET, ee +   ~ 1 TeV
- RS     (345pb-1)m1 ~ 220 to 690 GeV for k/MPl 0.01 to 0.1
-           *ee* +    (200pb-1) m1 ~ 200 to 700 GeV for k/MPl 0.01 to 0.1
-  Many new results and publications on their way....
-       *ee* PP search
-       *ZZ* channel
-  Tevatron Run IIa (2 fb-1) has a promising observation potential  	             and should be in a position to discover ED, if they exist,
-              ADD: up to about MS = 2 TeV
-              RS: m1 from 0.5 to1 TeV for k/MPl 0.01 to 0.1

- The highest limits obtained are from the ** channel.

-  Many interesting channels to look in.
-  Run II results already coming in
-  To be updated in the future...

- ADD ee +     939 (853)  GeV for =-1 (+1), KLED = 1.3
- 	 ADD jets+ET    995 for n=2, 768 for n=4
-         RS   ee            205 to 535 GeV for k/MPl 0.025 to 0.1

- Tevatron Run II has a promising observation potential  	              	and should be in a position to discover ED, if they exist,
- ADD: up to about MS = 2 to 3 TeV (Runs IIa, 2 fb-1; IIb, 20 fb-1)
-       RS: m1 from 0.5 to 1 TeV for k/MPl 0.01 to 0.1 (Run IIa, 2 fb-1)

**Look out for CDF results!**

## ADD Exchange Results

## Run II improvements EM calorimeter timing

- EM    Calorimeters

- Hadronic

- just completed Nov 04!

- Reducing the kinematic requirement would increase the signal by a factor of 2.8
- And decrease cosmic ray background

- 2/3 TDC’s installed in Summer 2003

##          constraints 

- Davoudiasl, Hewett, Rizzo  hep-ph 0006041

-          constraints

- RS

- m1 (GeV)

- 0.20
- 0.10
- 0.07
- 0.05
- 0.03
- 0.02
- 0.01

- 1000   2000   3000   4000   5000

- Allowed Region

- Sridhar hep-ph 0103055

- m1 :
- 700-1150 GeV

## Diphoton          constraints

- hep-ph 0103055

- Diphoton production at Tevatron Run II
- sensitive to mass of first KK graviton resonance
-  (m1) : 700-1150 GeV

- ADD K factor for both and ref and add bin sizes
- And know method – xhi Squ !?

- LHC:  can probe first graviton excitation up to ~ 3.5-5.5 TeV

- For K/MPl 0.01 to 0.1 95 % C.L. m0 Tevatron: 180-290 GeV

- implies mass of first KK graviton resonance must lie above 700 GeV

- 200 220 240 260 280

- m0 (GeV)

- K/MPl

- 0.1
- 0.08
- 0.06
- 0.04
- 0.02

- s = 2 TeV
-  L = 2fb-1

- 95 % C.L.

- 95 % C.L.

- m1 : 700-1150 GeV

- m1 : 3.5-5.5 TeV

**Tevatron**

**LHC**

- RS