# Presentation: 353418

## SUGRA Searches at the Tevatron

** **Dan Claes
*University* *of* *Nebraska*
- representing the
**CDF **and** ****D0 Collaborations**

- The Conference on Higgs & Supersymmetry
- Laboratoire de l*'*Accélérateur Linéaire
- Orsay, France
- March 19-22, 1999

## Slide 2

## “Precise measurement of the positive muon anomalous magnetic moment”

**“****Precise measurement of the positive muon anomalous magnetic moment”**
**(submitted to PRL February 23, 2001)**

***“******Many people believe***
***that the discovery of***
***supersymmetry may ***
***be just around the***
***corner.  We may have***
***opened the first tiny***
***window to that world.”***

***“******We are now 99 ***
***percent sure that ***
***the present ***
***Standard Model***
***calculations ***
***cannot describe ***
***our data.”***

********** ****= (*****g*********2)/2**
-  (SM)=11 659 159.6(6.7)10-10(0.57 ppm)
-  (SM)**** (exp)= 43(16)10-10

## Though just 51⁄2 years ago...

***Though just 51⁄2 years ago...***

## Fig. 2 Rb and Rc data [2] and the

**Fig. 2 *****R******b***** and *****R******c***** data [2] and the**
**SM predictions [5].**

##                                                                  SUPERSYMMETRYNew symmetry unifying particles of different spin within multiplets                             -solves “fine-tuning” provided MSUSY < 1 TeV                             -allows unification of the gauge couplings		-includes quantum gravity

##      Particle Name	        Symbol	 Spartner Name           Symbol           gluon                        g                         gluino                        g     charged Higgs               Hchargino                    W1,2 charged weak boson          light Higgs                    h                     neutralino                   Z1,2,3,4        heavy Higgs                  Hpseudoscalar Higgs            Aneutral weak boson            Z          photon                                  quark                        q                        squark                       qR,L           lepton                       l                         slepton                      lR,L

**~**

**~**

**~**

**~**

**~**

## Minimal Supersymmetric SM

**Extension adding the fewest new particles**

**2 Higgs doublet      *****h******0******  H******0******  A******0******  H***_***+***_
** *********     *****and ********described by 4 parameters**

-  **M****1 ****     ****U(1) **
** ****M****2****    ****U(2) *****gaugino mass parameter at EW scale***
*******higgsino mass parameter***
***tan ************ratio of *****VEV *****of Higgs doublets***

-  **scalar sector described by *****MANY***** ****mass parameters**
** ****different SUSY breaking       different class of models **

## MSSM Assumptions:

***SUSY particles are pair produced***
***Lightest SUSY particle ******(LSP) ******is stable***

## SUSY   Symmetry BreakingSUGRA GeV)

***Lightest SUSY particle is***

***5 free parameters***

***m******o******   ******common scalar mass***
***m******1/2****** ******common squark mass***
***A******o      ******trilinear coupling***
***tan***************
***sign(*********

## Signal Cross Sections

**Production**** has less **
**dependence on ****SUSY**
**parameters than ****decays**
**Squarks/gluinos**** dominant if kinematically accessible**
**Cross sections for scalar**
**leptons are small**

- Daniel Claes, University of Nebraska-Lincoln			   Higgs SUSY Conference 2001, Orsay

***Signal Cross Sections***

## Daniel Claes, University of Nebraska-Lincoln			   Higgs SUSY Conference 2001, Orsay

*If light*, **squarks** *and* **gluinos** *should be *
*copiously produced at the* **Tevatron**

*** ******g***

*** ******g****** ***

****
***q****

****
***q***

****
***q***

*** ******g***

****
***q***

****
***q***

***q***

***q***

## Daniel Claes, University of Nebraska-Lincoln			   Higgs SUSY Conference 2001, Orsay

****
***q***

******* ***
***g***

******
********* *****0****1**

***q***

******
********* *****0****1**

***q***

***q***

**Assuming ****R-partity**** is conserved, ****squarks**** and ****gluinos ****can decay**
**directly**** into the ****LSP**** (**********0****1****).**

**or cascade down to the LSP**

****

****
***q***

******* ***
***g***

***q***

- So that the dominant signature for  ***pp**********qq, qg, gg + X*** is jets+ET

****** ********  ******

***q***

***q***

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****
***q***

******
********0****2**

****
***q***

******
********* *****0****1**

****
***q***

******* ***
*** ******g***

****
***q***

***q***

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***q***

******
********* *********1**

***q***

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******
********* *****0****1**

****
***q***

## Daniel Claes, University of Nebraska-Lincoln			   Higgs SUSY Conference 2001, Orsay

***The 1992-1994 Tevatron Run***

**Cross sections for new physics is small**
**compared to Standard Model processes**

**But CDF and D0 both **
**recorded over 100 pb-1 of data**

## Daniel Claes, University of Nebraska-Lincoln			   Higgs SUSY Conference 2001, Orsay

***The 1992-1994 Tevatron Run***

**Precision tracking: vertexing,**
**b-tagging, lepton identification**

**Powerful calorimetry: *****e*****, ********, E****T**

## Daniel Claes, University of Nebraska-Lincoln			   Higgs SUSY Conference 2001, Orsay

***D0 MET and Jets Analysis***** **

*** ******pp  ***  ***q,g***  ******  jets + E****T**
- large branching ratio, but suffers from enormous backgrounds
***QCD*** multijet events w/faked ET
-  ***W/Z***+jets
* ****t t***

-  

**Used E****T**** trigger, basic selection criteria:**
**E****T****j1****>115, E****T****j3****>25 GeV**
**E****T****>75 GeV****	****	****	****	****  **
**jets and E****T**** not aligned                     **Reduce QCD
**H****T****(******** *****i *****>1****E*****i*****T****) > 100 GeV ****	****	**Reduce** **W/Z
**veto isolated ********** with P****T**** > 15 GeV     **Reduce W/Z

## Daniel Claes, University of Nebraska-Lincoln			   Higgs SUSY Conference 2001, Orsay

***Jet-E******T****** Correlations***** **

- Jet1

- Jet2

- Jet3

- ET

- 

- 3

- 1

**3.0**
**2.5**
**2.0**
**1.5**
**1.0**
**0.5**
**0.0**

**0              0.5              1.0              1.5              2.0               2.5              3.0**

- MET, Jet1 vs MET, Jet2

- Low Et JET MIN Trigger with offline Met > 10 GeV cut

## Daniel Claes, University of Nebraska-Lincoln			   Higgs SUSY Conference 2001, Orsay

***Jet-E******T****** Correlations***** **

## Daniel Claes, University of Nebraska-Lincoln			   Higgs SUSY Conference 2001, Orsay

***D0 MET and Jets Analysis***** **

**Final E****T****, H****T**** cuts tuned to optimize *****S***** / *********B***** **
**across (m0, m1/2) plane**
**79 pb-1 of data analyzed**
**Expected: ****8.3********3.5**** events     Observed: ****15**

**M*****q***** > 250 GeV (95% C.L.)**
**M*****g***** > 260 GeV (M*****g*****=M*****q*****)**
**M*****g***** ****> 300 GeV (small *****m*****o****)**

**~**

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**Phys.Rev.Lett. 83 4937 (1999); hep-ex/990213**

## Daniel Claes, University of Nebraska-Lincoln			   Higgs SUSY Conference 2001, Orsay

***D0 MET and Jets Analysis***** **

**Phys.Rev.Lett. 83 4937 (1999); hep-ex/990213**

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**M*****q***** > 250 GeV (95% C.L.)**
**M*****g***** > 260 GeV (M*****g*****=M*****q*****)**
**M*****g***** ****> 300 GeV (small *****m*****o****)**

## Daniel Claes, University of Nebraska-Lincoln			   Higgs SUSY Conference 2001, Orsay

***CDF MET and Jets Analysis***** **

*** ******starting with basic cuts similar to *****DO***** ***

**Missing E****T**** trigger**
**cleanup jets projected to calorimeter gaps**
**Blind Box method defines signal region by****:**
**E****T****>70 GeV****	****	****	****	****   **
**H****T****(******** *****i *****>1****E*****i*****T****) > 150 GeV ****	****          **
**N****trk****iso**** (isolated tracks)=0       **
- indirect lepton veto

## Daniel Claes, University of Nebraska-Lincoln			   Higgs SUSY Conference 2001, Orsay

**E****T** predominantly from mis-measured **QCD** events

## Daniel Claes, University of Nebraska-Lincoln			   Higgs SUSY Conference 2001, Orsay

**QCD E****T**** comparison:data(JET20+JET50) & predictions(Herwig)**

## Daniel Claes, University of Nebraska-Lincoln			   Higgs SUSY Conference 2001, Orsay

***CDF MET and Jets Analysis***** **

- Main backgrounds
- QCD, *W/Z*+jets, *tt*

## Daniel Claes, University of Nebraska-Lincoln			   Higgs SUSY Conference 2001, Orsay

***CDF MET and Jets Analysis***** **

**Expected: 76.02±12.8 events           Observed ****74**

## Daniel Claes, University of Nebraska-Lincoln			   Higgs SUSY Conference 2001, Orsay

***CDF MET and Jets Analysis***** **

**Expected: 76.02±12.8 events           Observed ****74**

- For mq  mg      mg > **300 GeV/c****2**
- For mq << mg    mg > **570 GeV/c****2**
- For mq >> mg    mg > **195 GeV/c****2**

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## CDF Dilepton + Jets Search

**CDF Dilepton + Jets Search**

**Squark ****& ****gluino**** cascade decays can *****also***** lead to ****dilepton final states**

*** ******pp ********** q, g  ********* ************1********0****2****+*****jj***
**        ******** *********jj *****+ E****T**

****
****

**Selection cuts on CDF’s dilepton trigger**:
**    ****2 ****isolated leptons****, *****P*****T**** > 11, 5 GeV**
**    ****2 ****central jets**** *****E*****T**** > 15 GeV, |*********** | *****< 2.4**
***    ******E*****T**** > 15 GeV**

***q***
*** ***
***q***

**~**** ****~       ~   ~**

***~***
***q***
*** ***
***~***
***q***

******0****2**
**    ************1**
***   ******q***

**~**

**~**

******0****1**

**~**

******0****1**

**~**

***Z****
***W****

*** ******g***

## CDF Dilepton Backgrounds

**CDF Dilepton Backgrounds**

**Heavy quark and di-boson production**

**Require LS leptons.  Final M******** cut rejects Z-production.**

## CDF Dilepton + Jets Search

**CDF Dilepton + Jets Search**

**Expect:**
**0.55********0.25********0.08 **
**       ****events**
**Observe:** **0 events**

## Dilepton mSUGRA Search

**Dilepton mSUGRA Search**

**Squark ****and ****gluino**** search through ****dilepton ****final states**

*** ******pp ********** SUSY ********* *********jj *****+ E****T**

- Selection, optimized for different regions of mSUGRA parameter space,
-                           made by (52 different) combinations of
**E****T****jet 1,2**** > 20 GeV** or **45 GeV**  (optionally, also require **E****T****jet3**** > 20 GeV**)
*ee* signatures:    **E****T*****e*****1**** > 17 GeV**,   **E****T*****e*****2**** > 15 GeV**
*e**** *signatures:   **E****T*****e***** ****  ****> 17 GeV**,   **E****T******** ****  ****>   4 GeV,  7 GeV  ****or****  10 GeV**
** signatures:  **E****T********1**** > 20 GeV**,   **E****T********2**** > 10 GeV**
**E****T****  >  20,  30,  **or**  40 GeV**

****
****

***q***
*** ***
***q***

***~***
***q***
*** ***
***~***
***q***

******0****2**
**    ************1**
***   ******q***

**~**

**~**

******0****1**

**~**

******0****1**

**~**

***Z****
***W****

*** ******g***

## Dilepton mSUGRA Search

**Dilepton mSUGRA Search**

_**Background sources**_
-  **QCD Multijet****, *****W*****+jets**
** ****estimated from data**
*** ******t t , Z + *****jets**** **
**SPYTHIA****-based Monte Carlo **
**   ****(****FMC0****)**
**108 pb****-1**** of data analyzed**

-  ***M******g***** = *****M******q*****  >  ****255**** GeV**
**95% C.L. for ****tan ********** = 2**

**~     **** ****     ~**

## Charginos and Neutralinos

***Charginos and Neutralinos***

**Production of  ************1  ********0****2**** will lead to *****trilepton****** *****final states**** ****with**** *****E*****T**
**perhaps the**** *****cleanest***** ****signature of ****supersymmetry****.**

*** ******pp ********** q, g  ********* ************1********0****2**
**        ******** ********* *****+ E****T**

****
****

**~**** ****~       ~   ~**

**********1**
**    **
******0****2**

**~**

**~**

******0****1**

**~**

******0****1**

**~**

***W****
***Z****

*** ******W* ***

***q***
***q************ ***

****
****

***q***
***q************ ***

**********1****    **
******0****2**

**~**

**~**

**********1**

**~**

******0****2**

**~**

********
****

**~**

******0****1**

**~**

********

*************
********

**~**

********

******0****1**

**~**

**~   ~**

***q****

**~**

## Trilepton + Jets Search

**Trilepton + Jets Search**

**Selection cuts **:
**    ******** ****3******** (*****e*****,**********) with *****P*****T**** > 5 ******** 22 GeV**
**    ****require Opposite Sign Leptons (CDF)**
***    ******E*****T**** > 10 - 15 GeV**
**    ******** ****mass and topological cuts**

***Both***** CDF and DO searched for *****trileptons *****(*****e,***********) in Run I**
**          ****PRL 80, 1591 (1998);       PRL 80, 5275 (1998)****   **

**Very low background**
**Drell-Yan**** + fakes**
**heavy flavor**** production**
***ZZ*****, *****WZ***

## Trilepton + Jets Search

**Trilepton + Jets Search**

_**CDF**_
**Expected**: **1.2********0.2**
**Observed**:** 0**

_**DO**_
**Expected**: **1.3********0.4**
**Observed**:** 0**

- 100<m0<2500 GeV/c2
- a) m1⁄2=50 GeV/c2
- b) m1⁄2=75 GeV/c2
- c) m1⁄2=100 GeV/c2
- d) m1⁄2=120 GeV/c2

## Daniel Claes, University of Nebraska-Lincoln			   Higgs SUSY Conference 2001, Orsay

**Run II Upgrades**** **

- Main injector

**Tevatron**

- DØ

- CDF

_**Accelerator upgrade**_
_**Run I**_**	****                         **_**Run II**_
***total integrated luminosity***
**120 pb****-1****	****	**** 2 fb****-1  ****/2 years**
**	****             ****         ****(20 fb****-1**** extended run)**
***instantaneous luminosity***
**4 - 20×10****30****/cm****2****sec      2×10****32****/cm****2****sec**
***bunch crossing intervals***
**3.8 ********sec****	****	**** 132 nsec**
***beam energy***
**1.8 TeV****	****	**** 2.0 TeV**
**complemented by major detector upgrades**

**Run II**** *****has begun****** with***
**Fermilab’s Main Injector**
**(commissioned June 1999)**
**New anti-proton storage ring**

## Daniel Claes, University of Nebraska-Lincoln			   Higgs SUSY Conference 2001, Orsay

**The DO Detector Upgrade**** **

- retain the uranium/liquid-argon calorimeter
- retain most of its full-coverage muon system
**     ****But** the entire tracking volume is being replaced
- shorter bunch spacing,
- higher radiation levels
- _	_
-          _**New Detector Elements**_
**inner silicon vertex detector**
**8 ****layers of**** scintillating fiber ****tracking**
**2 Tesla ****superconducting solenoid**
**scintillator-based preshower detecto         **

## Daniel Claes, University of Nebraska-Lincoln			   Higgs SUSY Conference 2001, Orsay

**DO Upgraded Triggering**** **

_**LEVEL 1**_  (trigger decisions within few sec)
- calorimeter trigger unchanged
- new fiber tracker trigger
- adds new preshower detector
_**LEVEL 2**_ (trigger decisions within 100 sec)
- global processors run algorithsm
- correlating info from different subdetectors
- e.g., calorimeter-preshower-track matches
- E/p and invariant mass cuts
- Event buffering between each trigger stage
- deadtime due to pileup decreased
- event transfer rates into **LEVEL 3** **1 kHz**
_**LEVEL 3**_** **
- rejection of 50
- average processing time < 100msec)

## Run II machine goals:

- 1)  Run IIa to achieve a luminosity of 5x1031 cm-2s-1
-      and an integrated luminosity of 2 fb-1
- 2)  Run IIb to achieve a luminosity of 2x1032 cm-2s-1
-      and an integrated luminosity of ~20 fb-1

- The number of anti-protons in the ring has
- been one of the major limiting factors in
- Tevatron luminosity. The anti-proton
- stacking rate will be increased to
- 2x1011/hr from 7x1010/hr
- The machine will operate with 36x36
- bunches (396 ns spacing) initially
- and (132 ns) eventually.

##  a new massive silicon vertex detector

-  **a new massive silicon vertex detector**
**  ****– ****7 ****layers extending to ****28**** cm in radius**
**  – ****deadtime-less ****SVX3**** readout electronics**
** ****a new central outer tracker (****COT****)**
** ****hermetic scintillator tile plug & forward calorimeter**
** ****large trigger bandwidth**

- Time-of-
- flight added

- End Plug
- extended
- to larger ******

- COT replaces CTC

- SVX replaced,
- Si layer added
- to beampipe,
- Intermed. Si
- Layers added

- Shower max edded

- Forward
- calorimeter
- eliminated

- + New Trigger, DAQ

##  entirely new tracking 

** ****entirely new tracking **
** ****improved muon spectrometer**
** ****new trigger and DAQ system**

**– ****2T super conducting solenoid**
**– ****disk/barrel silicon detector**
**– ****8 layers of scintillating fiber tracker**
**– ****preshower detectors**

- Forward Mini-
- drift chambers

- Shielding

- New Solenoid & Tracking:
- Silicon, SciFi, Preshowers

- + New Electronics, Trigger, DAQ

- Forward Scintillator

- Central Scintillator

## RunII Squark and Gluino Prospects 

***RunII Squark and Gluino Prospects***** **

- Multijets with **E****T** remains the dominant signature of ***q***’s &*** ******g***’s
-   **Critical **
- Understanding the tail of the ET distribution in multijet events
-  Methods to accurately estimate multijet backgrounds
- Large **tan*********** *****:**enhanced ***g*** /*************i*** /******** 0*****i****** ***decays to **3rd** generation particles
**Critical **
******-lepton and ***b***-quark trigger and
-  identification capabilities.

**~ ****   **** ****   ****  **** ****~**

**~ ****      ****~****   ****  ****   ****~**

## RunII Squark and Gluino Prospects 

- m1/2 up to ~150 GeV
- corresponding to
- Mgluino  400 GeV
- (for m0<200 GeV)

- Run II improvements:
- improved ET resolution
- 	– more hermetic calorimeter (**CDF**)
- 	– better vertexing (**DØ**)
- Advanced analysis methods, improved tools

- Daniel Claes, University of Nebraska-Lincoln			   Higgs SUSY Conference 2001, Orsay

***RunII Squark and Gluino Prospects***** **

## Chargino and Neutralino Prospects 

***Chargino and Neutralino Prospects***** **

- Trilepton signatures with
***        ******large****** ************ ******content***
- _Major backgrounds_:
- W+jets, Z+jets, WZ,...
_**Critical**_: large acceptances
- and high efficiencies for
- high & low pT leptons
- including ******

## Mchargino reach >150 GeV

***Chargino and Neutralino Prospects***

-                         Run II improvements:
-    1) extended coverage improves lepton acceptances
-    2) lepton charge and better ******  momentum
-         measurements reducing backgrounds (**DØ**)
-    3) new preshower detectors
-    4) major effort on ******  identification built upon
-        Run I experiences

**M****chargino**** reach >150 GeV**
***for most of parameter space***
- Mchargino reach ~200 GeV
***for small to medium values of*** **tan********