# Presentation: 477199

**Exotic Searches at the Tevatron**
-  Amitabh Lath
- For the D0 and CDF Collaborations

**Recontres Des Moriond**

## CDF Detector

**Extended spatial e, ****μ**** coverage**
**New plug calorimeter improves also MET**** ****measurement**

**New displaced vertex trigger (SVT)**
**New silicon and gas tracker**
**Upgrade of muon system**

**CDF Detector**

## Squark-gluino Search

-  ET > 175 GeV,
-   jet ET > 250 GeV

-  ET > 75 GeV,
-   jet ET > 250 GeV

## Squark-gluino Search

-  ET > 100 GeV,
-   jet ET > 325 GeV

**~**

## Search for Gluino  Sbottom

- Search for Gluino  Sbottom

-  b1 can be *very light* for large tan
-  Expect large branching fraction
-    of gluinos to sbottoms.

-  Distinctive signature:
- 	4 b-jets and ET

**~**

**/**

- Exp: 2.6 +- 0.7
**Obs: 4**

## Diphotons+Missing Energy 

- Diphotons+Missing Energy

- Typical GMSB signature from   decay
- Gaugino pair production  lightest neutralino

- Signature:     2 energetic photons + ET

**/**

**263 pb****-1**

- 0
- 1

- ~

- ( = 80 TeV)

## /

- Current results:
-      CDF    m(±)  > 167 GeV
-      D0       m(±)  > 195 GeV

**D0: E****T ****(********) >20 GeV, E****T**** >40 GeV**
**Expect:** 3.6±0.6 events
**Obs:**       2

- ~

- ~

- 1

- 1

**/**

**CDF: E****T ****(********) >13 GeV, E****T**** >45 GeV**
**Expect:** 0.3±0.1 events
**Obs:**       0

**/**

**Phys. Rev. Letters 94, 041801 (2005). **

**Accepted by Phys Rev. D.**

**Notes:**
Say that is on the wedge of being combined
cdf/d0: pt>13 /20
             met>45/40

## SUSY tri- & di-lepton searches

**Trilepton signature is one of cleanest SUSY signatures**
- Chargino-Neutralino production
**Decay to WZ (or sleptons) + 2 LSP**
**Low SM background**
- But also : Small x-section
**Leptonic Br are enhanced if slepton masses are close to gaugino (i.e. **************** in mSUGRA) masses.**
**Classic tri-lepton SUSY signature:**
**2 *****like-sign***** leptons signatures available**
**Strategy: **
**   ****Combine eel, ********μl, ****e****μl, μ****+-****μ****+-****, ********l********l**

## SUSY Trileptons

**eel:****    **
**     ****p****T**** 1,2,3 >**** ****12, 8, 4 GeV**
**     ****E****T**** x p****T3  ****> 220    GeV****2**

**2)********l:****    **
**     ****p****T**** 1,2,3 >**** ****11, 5, 3  GeV**
**     ****E****T**** x p****T3  ****> 150    GeV****2**

**3****rd**** track pt**

**Expected BG:  0.21+- 0.12**
** ****Observed:        0**

**Expected BG:  1.75 +- 0.57**
** ****Observed:        2**

## SUSY Trileptons

**3)********e********l:****    **
**     ****p****T**** 1,2,3 >**** ****12, 8, 7  GeV**
**     **

**4)********like-sign********:****    **
**     ****p****T**** 1,2 >**** ****11, 5  GeV**
**     ****E****T**** x p****T2  ****> 300    GeV****2**

**Expected BG:  0.31 ****+0.15****–0.12**
** ****Observed:        0**

**Expected BG:  0.66 +- 0.37**
** ****Observed:        1**

## SUSY Trileptons, with 

**5a)********e********l****************hadronic decay**
**     ****p****T**** 1,2,3 >**** ****8, 8, 5  GeV**
**     ****E****T**** x p****T(track)  ****> 350  GeV****2**

**Expected BG:  0.582 ****+0.112**** ****-0.105**
** ****Observed:        0**

**Expected BG:  0.36 +- 0.12**
** ****Observed:        1**

**5a) ********l****************hadronic decay******
******p****T**** 1,2,3 >**** ****14, 7, 4  GeV**
**     ****E****T**** x p****T(track)  ****> 250  GeV****2**

## SUSY Trileptons, Combined Result

**Huge improvement on Run 1 ****(~1.5 pb limit)**

**W. Beenakker et al., **
**Phys. Rev. Lett. 83, **
**3780 (1999****)**

****** ****helps!**

## Charged Massive Particles

**L=390 pb****-1**

**Gaugino-like chargino > 174 GeV/c****2**
**Higgsino-like chargino> 140 GeV/c****2**

**CHAMPS look like muons.**
** ****- inv mass, speed inconsistent**
**    ****with beam-production.**
** ****- speed significance = ****1-speed**
**                           ********(speed)**
** ****- significance > 0 **
**    ****for both muons**** **

**CDF Champs search:  (85 pb****-1****)**
**          ****M_stop > 108 GeV/c2 **

**O****  ****data**
** ****60 GeV **
**    ****stau**

## No large ET

- pp t t  b b

- ~

- ~

- No large ET
- requirement
- possible!

- control

**Z************ **
**visible**

**Biggest background:**
** ****Real ******** from Z**********

**Signal**

## SuperSymmetry (RPV)

**Expect: 4.8 ******** 0.7 events               **
**Obs:  5**
- m(t1)> 129 GeV/c2

**~**

**3****rd**** Gen. LQ also ruled out **
**at m>129 GeV/c****2**

## Large Extra Dimension (LED)

**Dilepton and diphoton channels:**
** ****Monojet channel where a jet recoils**
**     ****against the graviton which leaves **
**     ****the usual 3D dimension.**

- G

- g,q

- g,q

- jet

-  ηG = F/MS4
-  F is a *model dependent* dimensionless parameter ~ 1:
-  **GRW**:       F = 1
-  **HLZ**:
-     F = log(Ms2/M2),   n =2
-         F = 2/(n-2),          n > 2
**Hewett**:
-      F = 2 **λ**/π,           **λ** = ±1
-          Ms is UV cutoff =
-                         MPL(3+n dim)

- G. Giudice, R. Rattazzi, and J. Wells, Nucl. Phys. **B544**, 3 (1999)

- T. Han, J. Lykken, and R. Zhang, Phys. Rev. D **59**, 105006 (1999)

- J. Hewett, Phys. Rev. Lett. **82**, 4765 (1999).

## LED with ee & 

| GRW | HLZ for n =  | Hewett |
| --- | --- | --- |
|  |   2      3      4      5      6      7  | λ = +1/-1 |
| 1.36 | 1.56  1.61  1.36 1.23  1.14  1.08  | 1.22/1.10 |
| 1.43 | 1.67  1.70  1.43 1.29  1.20 1.14  | 1.28/NA |

- DØ RunII

- DØ RunI + Run II

- LED with ee & 

- QCD

- SM
- prediction

- Signal
- prediction

**Limits on Fundamental Planck Scale,  in TeV**

## ED with di-photons

- pp G 

- L. Randall and R. Sundrum,
- Phys. Rev. Lett. **83**, 3370 (1999).

## W’: additional charged heavy vector boson
appears in theories based on the extension of the gauge group 
e.g. Left-right symmetric models: SU(2)R    WR
assume: the neutrino from W’ decay is light and stable.
signature: 

**appears in theories based on the extension of the gauge group **
**e.g. Left-right symmetric models: SU(2)****R****    W****R**
**assume: the neutrino from W’ decay is light and stable.**
**signature: **

- W’ search in e channel

- MC only

- high pT electron + high ET

## W’ search (cont.)

- No events above SM expectation,  set limits on W’ production rate
- use binned likelihood fitting method
- two types of systematics are examined as a function of MT :
- affect **event rate**
-          (dominant: PDF, ~14%)
- affect **the shape**
-       (dominant: electron energy scale, ~16%)
- *B(W’    e) limit:  ~ 50 – 100 fb for M(W’) > 500 GeV/c2 at 95% CL.

- Limit: M(W’SM )> 842 GeV/c2

- Run I results (with the same assumptions):
- M(W’SM )>  754 GeV/c2

- W’SM

- Limit

**Notes:**
W’ limits from runI:  CDF enu: 754 GeV (run I, 110 pb-1), munu:646 GeV (run Ib, 89pb-1)
Do:720 GeV (79 pb-1)  from enu GeV, also limits for the case N is heavy, decay to eqq, 650 – 720 GeV

## Searches in high mass dileptons (cont.)

**ee**

**ee**
- both-forward

****

****

- both-central or
- central-forward

## *BR Limits  (X ee or )

- spin-0  	        spin-1  	                  spin-2

- spin-0                            spin-1                              spin-2

*****Br limit: ~ 25 fb for all spins for the high mass region (Mll > 600 GeV)
- These limit curves can be compared with many models
- Individual channel limits are still very important - lepton universality ?

## Spin-1, Z’ limits

**SM Couplings****    ee      ********    ee+********    ******
**      ****CDF :              ****750    735    815       394**
**      ****DØ:                 ****780    680**
**        ****E****6****  ****           Z****I****     Zχ      Zψ    Zη **
**      ****CDF:           ****610  670   690  715   ****(ee+********)**
**      ****DØ:             ****575  640   650  680****   (ee)**

- z’ mass limits (in GeV/c2)

- ∫Ldt = 200 pb-1

- ∫Ldt = 250 pb-1

**D0:  ee**

**CDF:  ******

**D0:  ******

## Leptoquarks (direct searches)

- Carry both lepton (L) and baryon (B) numbers
- Couple to quark and lepton **of the same generation**

- At the TeVatron they are
- pair produced

- Their decay is controlled
- by ****** = BR (LQ********lq )**

- Experimental signature:
**high P****T**** isolated lepton(s)  (********=1)**
***or***** E****T ****+ 2 jets (********=0)**

- 3 generations

## 1st,  2nd  and 3rd  Generation LQ

- channels: eejj, ejj, (jj)

- for =1,
- D0: Run I + II, MLQ > 256 GeV/c2
- CDF: Run II, MLQ > 235 GeV/c2

- channels: jj, jj, jj

- for =1,
- D0: Run I, MLQ > 200 GeV/c2
- CDF: Run II, MLQ > 224 GeV/c2

**1****st**** Gen**

**2****nd**** Gen**

**3****rd**** Gen.**** LQ ruled out by CDF**
**at ****m>129 GeV/c****2**** ****   ****(********=1)**** **
***See the RPV stop search***

**Notes:**
nnjj channel, combined (CDF), 85pb-1 data analysed by D0 for nnjj.  Not combined for this plot.

## Bs 

- Bs 

- Complementary to other SUSY searches, *indirect *
- BR could be enhanced from new physics:
-     	loop decays (MSSM, mSugra) or direct (RP)
-  Challenging:    SM prediction is 3.4 x 10-9 ...

- Sidebands and
- same-sign data used to optimize cuts and check background estimates

**SM signal**
**x 10 ****5**

**Use lifetime information to reduce backgrounds**

## Bs 

- Combined:
- BR(Bs) < 2.7 x 10-7
- BR(Bd ) < 1.5 x 10-7 (CDF)

- 90% CL

- hep-ph/0411216

- _CDF (171pb__-1__) _
-   Expect:  1.05 ± 0.30
-   **Obs :      1**
- _D0(240pb__-1__)_
-    Expect:  3.7 ± 1.1
-    **Obs:       4**

**SM expectation**

- Now

- 8fb-1

- Bs 

**Notes:**
Not yet probing SM but can exclude areas of SUSY parameter space

## Summary and Conclusions

**Presented: some of the more recent preliminary results****  **
**Surpassed the sensitivity and results of Run I**
**Limits shown either exceed any published results of direct searches or are the first limits ever!**
**Limits shown with 200 – 300 pb****-1**** of data**
- We have about **600 pb****-1** of data on tape (per detector)
- We will eventually get **2 to 4 fb****-1**
**Interesting regions of parameter space **
**   ****(for many models) are now in reach.**

- Many new exciting results from Tevatron experiments  and more coming soon!

- .BR upper and mass lower limits on various new physics models @ 95 % using 200 pb-1 of CDF II high mass *ee*+****+**** data

## Backup

## Run II Tevatron Performance

**Operating extremely well with recycler.**
**highest Lum: ****1.052 e32 cm****-2****sec****-1****,Jan,2005**
**single store high ****:5.05 pb****-1****,  Jan,2005**
**Analyses presented here are using  up to**
**       ****~ 345 pb****-1**** ****of data **

- FY2002

- FY2002

- FY2003

- FY2003

- FY2004

- FY2004

**FY2005**

**FY2005**

***Highest  Energy Collider in Operation!***

**place to search for new physics**

**CDF**

**D0**

**P**

**P**

**√****s ******** 1.96 ****TeV**

**Int. Lum.**

**Peak Lum.**

## Supersymmetry at the Tevatron

- Supersymmetry at the Tevatron

- Looking for supersymmetric partners of SM particles

- Frameworks used:
- Minimal Supersymmetric   extention of the SM (MSSM)
- minimal Supergravity (mSugra)
-  Gauge mediated Supersymmetry Breaking (GMSB)

- Expected cross
- sections: SMALL!

- New quantum number:

- Excesses in SM-like channels and SUSY-only signatures

**Notes:**
Popular (among experimentalists because of clean signatures

## Lepton Signatures

-  Standard Trileptons (D0)
-  RPV Stops (CDF)
-  RPV Smuons (D0)
-  Bs   (both)

- Also plentiful in SUSY both RP and RP
-     - cascade decays from charginos, neutralinos, sleptons
- Most models predict low pT, non-central leptons
- High tan SUSY models predict -signatures

- /

-     l , 	 l l,    ll 

- ~

- ~

- ~

- ~

- ~

- ~

- ±
- 1

- 0
- 2

- 0
- 1

- 0
- 1

## Extra Dimensions (ED)

- Alternatives to SUSY for solving the hierarchy problem (MEW << MPlank ?)
- Focus on:
- Models with n extra spatial dimensions
- _Large ED (ADD):_
- n>0 (n>2) compactified
- M2PL~RnMsn+2, Ms: string scale
- _TeV-1 ED (DDG):_
- n>=1 (n=1)
- Mc: compactification scale
- _Warped ED (RS):_
- n=1, highly curved
- k/MPl, k: curvature scale

- Arkani-Hamed, Dimopoulos, Dvali
- Phys Lett B429 (98)

- Dienes, Dudas, Gherghetta
- Nucl Phys B537 (99)

- Randall, Sundrum
- Phys Rev Lett 83 (99)

- ee
****
****

- jet(s)+ET
-  + ET

- G

- G

- g,q

- g,q

- g,q

- g,q

- f

- f

- jet

- exchange

- emission

## LED with 

- pT > 15 GeV for both muon objects
- Isolated tracks
- M(mumu) > 50 GeV
- Cosmics removed
- Weighted average PT correction

- Observed  events ~ 17,000 events

- No deviation from SM in data

| GRW | HLZ for n =  | Hewett |
| --- | --- | --- |
|  |   2       3       4      5       6       7  | λ = +1/-1 |
| 1.09 | 1.00  1.29  1.09 0.98  0.91  0.86 | 0.97/0.95 |

- DØ ∫Ldt = 250 pb-1

**LED with ******

- Lower limits on the fundamental Plank scale, MS in TeV

## Randall-Sundrum Graviton (ee + + )

- 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.

- Clean experimental signature. Low backgrounds

- gg initiated process

- Dilepton Channel

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

- Add Run I limits?!

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

****

## mSUGRA

** ****Squarks and gluinos generally not expected to be lighter than others **
**    **
** ****However, large parameter space can accommodate various mass spectra**

-  **Many results below are interpreted in mSUGRA framework**
** ****Simplest SUSY model – good benchmark**
** **
** ****Requires only 5 parameters **
** ****(Very) restricted by LEP**

**mSUGRA**

**Typical mass spectrum in mSUGRA**

**Masses and mixing angles can be determined solving RGE with SM constraints**

**Highest MET event**

## Leptoquarks

** ****Predicted in many Grand Unification extensions of SM**
** ****Carry both lepton and color quantum numbers**
** ****Family diagonal coupling to avoid FCNC beyond CKM mixing*****  ***

**Leptoquarks**

**Searched first generation LQ in channels : eejj and e********jj**

## First generation LQ : eejj channel 

- First generation LQ : eejj channel

-  Background:

-  Drell-Yan/Z + jets,
-  QCD (with 2 fakes EM)
-  tt̅

- L  175 pb-1

- ee invariant mass

-  **Selections **
**Electrons : Et > 25 GeV**
**Jets : Et > 20 GeV, |eta|<2.4**
**Z veto**
**S****T**** > 450 GeV **
**Signal Eff = 12 – 33 % **

## eejj candidate event

**Invariant mass 475 GeV/c****2****, cos ****θ* = 0.01**

## Jet Energy Scale Corrections

-  Correct the measured energy:

- Offset: electronic noise, uranium noise, underlying event
- zero bias and minimum bias events (data)

- out of cone Showering:
- energy density in ring around the jet axis (data)

- Response: Emeas/Edeposit  1
- imbalance energy in  +jet events (data)

## Jet Resolution

-  Jet PT resolution:

-  using energy asymmetry in dijet events

- parametrized as:

- N = 0.0  2.2, S = 0.902  0.045, C = 0.052  0.008

## Resonant Smuon Production

-         produced via RP
-          decay
- Result: 2 muons, 2 jets, and _*no *__E__T_
-     i.e. possible to reconstruct
-    mass chain

- Assume prompt   decay
- Soft leptons and jets:
-  pT (2)  10 GeV
-  pT (leading jet)  25 GeV

- ~

- ~

- ~

- ~

**/**

**/**

- Can reconstruct   and  masses
- Use this to suppress backgrounds

- 0
- 1

- Mass:
- 102 GeV

- ~

- 0
- 1

- 0
- 1

-  ́211

- u

- -

- d

- -

- ~

- -

- d

- -

-  ́211

- u

- -

- +

- ~

- 

- 0
- 1

- ~

## In 154 pb-1 :

- In 154 pb-1 :
-    See 2 events
-    Expect 1.2 ± 0.3 from backgrounds

- Limit on  ́211 coupling

- Limit on cross section

-  More data is on the way, almost 500 pb-1  for 2005
- 	 Lots of room to make discoveries before LHC

## Diphoton + Smuon backup

## Run II Bs  

- CDF: (171 pb-1)    c > 200 m    (Bs ,vertex) < 0.1 rad    mass window: 3

- D0: (240 pb-1)
-     Lxy/Lxy > 18.47
-     (Bs ,vertex) < 0.2 rad
-     mass window: 2

- 				  Bs
-          CDF  <  5.8 ·10-7        1.5 ·10-7  (90% CL)
-          D0     (240 pb-1)     <  3.8 ·10-7
-         _Combined:__              < 2.7 __·__10__-7__ @ 90% CL_

## Stop to tau b backup