# Presentation: 789537

***The Search for Supersymmetry and Beyond the Standard Model Physics at the Fermilab Tevatron***
**David Toback**
**Texas A&M University**
**For the **
**CDF and DØ collaborations**

## Tevatron Searches:Looking Back and Looking Forward

**The LHC era has started but the Tevatron is still collecting data and leading the search for Supersymmetry and Beyond the Standard Model Physics**
**It’s been 10 years since the Fermilab SUSY-Higgs Workshop ******** take time to look back and remind ourselves what we focused on back then**
**Use this as a context for today’s searches to provide insight about what things might look like 10 years from now**

***“******Don't look back — something might be gaining on you."  ***
**-Satchel Paige**

**Most results today with between 1 and 3 fb****-1**** of data**

## The SUSY-Higgs workshop was held in 1998 to study the prospects for the Tevatron
5 main topics:
mSUGRA
GMSB
RPV
BSM (Extra Dimensions)
Higgs
Clearly envisioned much of the very broad and deep Tevatron search program
What’s different in our thinking? 
What’s the same?

**5 main topics:**
**mSUGRA**
**GMSB**
**RPV**
**BSM (Extra Dimensions)**
**Higgs**
**Clearly envisioned much of the very broad and deep Tevatron search program**
***What’s different in our thinking? ***
***What’s the same?***

**mSUGRA:**** Still at the forefront of our searches**** ******** benchmark model for SUSY**
**GMSB:**** Came into vogue after the Run I CDF ee********+Met candidate event. Still popular today**
**RPV:**** Harder to decide what versions are important**
**BSM:**** Many of these models have been searched for in great detail, (W’, Z’, leptoquarks, etc) **
**Notable exceptions: ****Extra Dimensions ****which has taken on prominence since 1998**
**Long-lived heavy particles**
**Higgs:**** Compelling as it ever was**
***Omissions? Not envisioned?***
**No model-independent search methods **
**Precision Cosmology data**

***“******There are some theories that are so compelling that it’s worth doing a comprehensive and systematically deep set of searches to see if they are realized in nature” – *****Anonymous**

**Run II SUSY-Higgs Workshop View**

## Cosmology and Particle Physics?

_**Cold Dark Matter**_
**Favored by most Cosmological models**
**Minimal Solution ******** A particle produced in the early Universe is stable and weakly interacting ******** still here today**
**Lots of Supersymmetry models have a lightest particle that fits this description**
**The minimal SUSY model that incorporates supergravity grand unification is known as mSUGRA ******** our baseline Cold Dark Matter search model**

_**Non-Minimal Solution/**_
_**Warm Dark Matter**_
**Warm Dark Matter consistent with Astronomical data and inflation models**
**Many non-Minimal solutions to the Dark Matter we observe today**

**Stable on the timescale of inflation**

**Stable on the timescale of the Universe**

_**Dark Matter is more complicated/Not directly specified**_
**Infinite variety of Models to check for**
**Search for the most compelling theories**
**CHAMPS**
**Extra Dimensions**
**Another possibility: *****We’re at the Frontier! just look for Hints (you idiot)!***

***Cosmology and Particle Physics?***

******SUSY DM**** ****≟**** ********CDM**** **

## Golden Channels

**Three main ways to look for minimal/Cold Dark Matter Models in mSUGRA type models**
**Direct production of Squarks and Gluinos**
**Heavy, but strong production cross sections**
**Direct production of the Gauginos**
**Lighter, but EWK production cross sections, also leptonic final states have smaller backgrounds**
**Indirect search via sparticles in loops**
**Affect branching ratios**

**Start with low tan********, then move to searches with high tan******

## Squark and Gluino Searches in Multijet + Met

**Three main production diagrams**
**Final states are mass dependent**

**3 separate final states + Unified Analysis ******** best coverage**

**2 jets + MET**

**3 jets + MET**

**4 jets + MET**

## Comparable results from CDF public and nearing publication

**Unified Squark/Gluino Search**

**2 jets + MET**

**3 jets + MET**

**4 jets + MET**

**SUSY Interpreter**

**DØ, PLB 660, 449 (2008) **

## Gaugino Pair Production in Multilepton + Met

**Gaugino Pair Production in Multilepton + Met**

**Chargino-Neutralino gives three leptons in the final state**
**Dominates the production cross section**

**5 separate final states + Unified Analysis ******** best coverage**

**3 Tight Leptons **
**+ MET**

**2 Tight leptons**
**+1 Loose lepton**
** ****+ MET**

**1 Tight lepton**
**+ 2 Loose leptons**
** ****+ MET**

**2 Tight leptons**
**+ 1 track**
** ****+ MET**

**1 Tight lepton**
**+1 Loose lepton**
**+1 track**
** ****+ MET**

**Tight (= high purity) and Loose (=not as high purity, but better efficiency) leptons are e’s or ********’s**

**Tracks can be e’s or ********’s or **_****__**’s**_

**eee, ee********, e******** ******

**eee, ee********, e******
**ee********e******

## Unified Gaugino Pair Production Analysis

**Unified Gaugino Pair Production Analysis**

**SUSY Interpreter**

**Comparable results from DØ**

| Channel | Background | Obs |
| --- | --- | --- |
| 3 Tight | 0.49±0.04±0.08 | 1 |
| 2 Tight + 1 Loose | 0.25±0.03±0.03 | 0 |
| 1 Tight + 2 Loose | 0.14±0.02±0.02 | 0 |
| Total Trilepton | 0.88±0.05±0.13 | 1 |
|  |  |  |
| 2 Tight + 1 Track | 3.22±0.48±0.53 | 4 |
| 1 Tight + 1 Loose + 1 Track | 2.28±0.47±0.42 | 2 |
| Total Dilepton +Track | 5.5±0.7±0.9 | 6 |

**CDF, Submitted to PRL, **
**arXiv:0808.2446**

## High Tan

**Likelihood fits including Higgs mass limits, *****g-2*****, and other experimental data to the MSSM in the plane of m****1/2**** and tan******** **
**Prefers high Tan******
**Stop and Sbottom masses can be very different than the other squark masses**
**Gaugino branching fractions to ********’s can rise to 100% as the stau gets light... **

**Emphasis on tan******** just starting during SUSY-Higgs Workshop**
**Now we have a full suite of high tan********targeted searches**

**Allanach, PLB 635, 123 (2006)**

## Sbottom Searches

**Sbottom Searches**

**Two primary Sbottom searches in *****b*****+jets+Met **
**Sbottoms from gluinos **
**Direct sbottom pair production **

**DØ, PRL 97 171806 (2006)**

## Stop Searches

**Stop Searches**

**Charm+jet+MET**

**Dileptons+Jets+MET**

**Dileptons+Jets+MET**** **
**Fit for Stop Admixture**

**M****Stop****=**
**155 GeV**

**M****top****=**
**175 GeV**

**3 Analyses**

**Complementary search for Squarks:**
**    ****Jets + ********+ Met**

## The search for Bs   is perhaps the most sensitive to SUSY since sparticles show up in loops
Especially sensitive at high tantan

**The search for B****s**** ******** ******** is perhaps the most sensitive to SUSY since sparticles show up in loops**
**Especially sensitive at high tan********tan**************

**Preliminary Combined CDF/DØ**
**BR(*****B******s******→μμ *****)<4.5x10****-8**
**@95%**

**BR****SM****=3.5x10****-9**

**Indirect Search: ****B****s**** ******** ******

**CDF, PRL 100, 101802 (2008)**** **

## Long-Lived Charged Sparticles (Champs)

**Long-Lived Charged Sparticles (Champs)**

**New emphasis in the theory community about the role of long-lived sparticles in the ****Early Universe and today as Dark Matter **
**Use timing techniques  measure the “mass” of weakly interacting charged particles (muon-like)**

**Interpret as Staus or Charginos **

**DØ, **
**Submitted to PRL, **
**arXiv:0809.4472**

**CDF also interpret as Stops**

## More natural solution for FCNC problems than mSUGRA

**More natural solution for FCNC problems than mSUGRA**

**Gauge-Mediated SUSY Breaking Models**

**CDF Run I ee********+Met **
**candidate event**

**Nanosecond lifetimes**

## All Neutralino Lifetime Searches

**Preliminary studies indicate that the 0 ns lifetime results from DØ should hold up to a lifetime of about a ns **
**Fall off quickly after that**

**Measure the time of arrival of photons in **
******+Met+Jet events**
**Not envisioned in SUSY-Higgs Workshop**

**Just starting to enter the Cosmology **
**Favored Region**** **

**CDF, PRL 99, 121801 (2007)**

**CDF, PRD 78, 0321015 (2008)**

**DØ, PLB 659, 856 (2008) **

## Other stuff

**A number of things in the SHW that were never really addressed again for example track with “Kinks”**
**Lots of things searched for but no hints found... (no time for them here...)**
**R-Parity Violating SUSY Scenarios**
**Technicolor**
**Excited/composite quarks & leptons**
**Leptoquarks**
**Extra generations (b’ & t’)**
**Extra gauge groups (W’ & Z’)**
**Others**

**Move on to Extra Dimensions**
**Then to model-independent searches**

## Extra Dimensions

**Extra Dimensions**

**Lots of different types of models**
**Two primary production types**

**Real graviton emission**

**Virtual graviton exchange**

**Single Jet **
**+Met**

**Single Photon + Met**

**1) Mass resonances in ee and/or ******
**2) Production enhancement**

## Unified Graviton Emission Analysis

**Unified Graviton Emission Analysis**

**LED Interpreter**

**Combine both analyses to improve the sensitivity to the Plank Scale M****D**

**Single Jet + Met**

**Single Photon + Met**

**CDF, Submitted to PRL, **
**arXiv:0807.3132**
**Comparable results from DØ nearing publication**

## Unified Graviton Exchange Analysis 

**Unified Graviton Exchange Analysis **

**LED Interpreter**

**Combine both distributions to improve the sensitivity to M****S**

**Invariant Mass**

**cos ********* Distribution**

**Combine ee and ******** Final States in the same analysis**

**DØ, Submitted to **
**arXiv:0809.2813**

## Unified Randall-Sundrum Graviton Analysis

**Comparable results from CDF in the ******** final state**

**LED Interpreter**

**Search the combined data set to improve the sensitivity to M****S**

**Look for Invariant Mass**
**bumps**

**Combine ee and ******** Final States in the same analysis**

**DØ, PRL 100 091802 (2008)**

## Model-Independent Search Strategies

**We’re sitting at the high energy frontier... we know what the SM should look like ******** Just do some hint finding**
**Look for any distribution that doesn’t look SM-like**
**Sleuth first published in 2000 ******** Not envisioned in the SUSY-Higgs workshop**

**Categorize each event by it’s final state and systematically look at **
**distributions**

**Especially useful in case our targeted searches are looking in the wrong places **
**Remember that the CDF ee********+Met Candidate was unexpected...**

## Look for Systematically “unlikely” Distributions

**Enormous numbers of distributions and dataset considered **
**Variation is largely as expected in 2 fb****-1**
**Some appear anomalous but none are suggestive of “new physics”, rather over or underestimation of systematic errors**

_**Sleuth**_
**Emphasis on high P****T**** tails**

_**Bump Hunter**_
**New resonant production**

_**Vista**_
**Gross features of the data**

**CDF, Submitted to PRD RC, **
**arXiv:0809.3781**
**1fb****-1**** in PRD 012002 (2008)**

## Conclusions

**The search program for Supersymmetry and Beyond the Standard Model Physics at the Fermilab Tevatron is both deep and broad**
**Unfortunately, despite almost 3 fb****-1**** of data analyzed there is no sign of new physics**** **
**Observations from the perspective on the grand plans of the SUSY-Higgs Workshop**
**Lots of talk about how easy it will be to combine final states and CDF/DØ results**
**	********8 years in: **
**Finally publishing first unified analyses**
**Only two examples of combined CDF and DØ SUSY search results**
**Experiments have focused on doing more and better searches rather than combining**
**Clear vision of searches to be done******
**The searches in 10 years will likely look different from what we predict now**
**Some of the questions will be answered, some exciting new things will die away, things we never envisioned may come to dominate our every day thinking**

**Perhaps things will LOOK different at the LHC**
**Maybe we’ll discover Split-SUSY quickly and spend the next 10 years measuring it**