Slide 1Searching for New Particles at the Fermilab Tevatron Dave Toback Texas A&M University Department Colloquium September, 2004OverviewOutlineThe Known Particles*The Known ParticlesReviewFermilab TevatronInside the AcceleratorBig Toys: The CDF detectorSlide 11The storyColor coding the recurring themes in the story…The history beginsSlide 15Slide 16Signal Vs. BackgroundSearch for anomalous gg events at CDFThe interesting event on the tailPredicted by the Standard Model?Predicted by Supersymmetry?Supersymmetry?Set limits on the modelsWhat to do?Model Independent SearchesUnknown Interactions: ExampleExample “cousins” Searchgg + Jets Search at CDFRepeat many times for gg+”Something”Another Cousins SearchLepton+Photon Cousin Search ResultsHmmm…Another hint? mmggjjSleuthA New Model-Independent Search Method: SleuthSlide 35Testing SleuthSleuth cont….Look in lots of final statesWhat to do? Results since 2000Preliminary CDF Run II DataA new CDF Run IIa Event CandidateAnother Event…Last Couple Years → Next Couple Yearseg+Energy ImbalanceAnother upgrade: EMTimingHardware for EMTiming ProjectPreliminary System SensitivityCan we Search for Long-Lived Particles which decay to photons?Compare Supersymmetry vs SMSensitivity vs Timing ResolutionComparing the sensitivityThe plan for the next ~5 yearsThe next 10 or so years: LHC*ConclusionsSlide 55Run II LuminosityFermi National Accelerator LaboratorySlide 58Slide 59Strategy TodayModels with PhotonsSummarizing the Sleuth ResultsSo where are we?Improved ConfidenceAn upgrade to CDF: EMTimingSlide 66PicturesTiming distributionsFun check: Time of arrival of Beam-Halo vs. PositionSearch for Long-Lived Particles?Timing in the CalorimeterCompare GMSB vs. SM in gg+MetDavid Toback Sept 20041Searching for New Particles at the Fermilab Tevatron Abstract Since the discovery of the top quark there have been a number of experimental hints that may be indicative of new, unpredicted particles to be discovered at the Fermilab Tevatron. In this talk I will discuss some of these hints and my program to both follow up on them and systematically uncover other hints. The bulk of the talk will concentrate on the search methodology and the results in the preliminary data. However, I will also discuss the work in progress as well as some of the prospects for next few years when lots of new data comes in.David Toback Sept 20042Searching for New Particles at the Fermilab TevatronDave TobackTexas A&M UniversityDepartment ColloquiumSeptember, 2004David Toback Sept 20043Overview•Since the discovery of the 6th and final(?) quark at the Fermilab Tevatron, the field of particle physics continues to progress rapidly•During that data taking run, and since, there continue to be a number of exciting experimental hints from Fermilab that there may be other, undiscovered, fundamental particles just around the corner•This talk describes following up on some of these hints and how we are trying to turn up othersDavid Toback Sept 20044Outline•The Standard Model of Particle Physics, Fermilab and looking for new particles•The story so far… Some hints of new particles•Model Independent Search Methods•What we’ve learned so far…–Results of many searches–Some interesting new hints!•Setting up for the future…–The prospects for the next couple of years and beyond…•ConclusionsDavid Toback Sept 20045The Known Particles*•Why do we need so many different particles?•How do we know we aren’t missing any?•Lots of other unanswered questions…The Standard Model of particle physics has been enormously successful. But:*Not a review of particle physicsDavid Toback Sept 20046The Known ParticlesMany theories/models attempt to address these issues, but none have been experimentally verifiedMany credible reasons to believe there are new fundamental particles out there to be discoveredDavid Toback Sept 20047ReviewHow does one search for new particles at the Tevatron?•Bang a proton and an anti-proton together and look at what comes out (an event)•We know what Standard Model events look like•Look for events which are “Un-Standard Model Like”David Toback Sept 20048Fermilab TevatronThe worlds highest energy accelerator–Proton anti-proton collisions–Center of Mass energy of ~2 TeV–1 collision every 395 nsec –>(2.5 Million/sec)4 Miles AroundDavid Toback Sept 20049Inside the AcceleratorDavid Toback Sept 200410Big Toys: The CDF detectorSurround the collision point with a detector and look at what pops out…Requires about 600 friendsPeopleDetectorDavid Toback Sept 200411Big Toys: The CDF detectorSurround the collision point with a detector and look at what pops out…Requires about 600 friendsDavid Toback Sept 200412The story•Looking for new particles predicted by theory is, in general, well prescribed –not easy… but often straight-forward•Goal: Hope we guess the right theory and that we have sensitivity (this worked for the top quark)Side benefit: Sometimes searching in systematic ways uncovers something unexpected and starts a whole new directionDavid Toback Sept 200413Color coding the recurring themes in the story…Three recurring themes…1.Golden Events•Individual events which don’t look SM-like and thus could be “hints” of what the new particles might look like2.Null Results or Theory that doesn’t explain the data•Mother Nature is fond of teasing those who try to understand her•Theories of new particles haven’t helped as much as we would like 3.New ideas or new techniquesDavid Toback Sept 200414The history beginsThe story begins with a search for Supersymmetry•One of the most promising theories of new particles (for MANY reasons not discussed here) –Potential for helping with Grand Unified Theories–Cold Dark Matter candidate/Cosmology connections–Etc…•Well developed and motivated•Each Standard Model particle has a Supersymmetric partner to look forDavid Toback Sept 200415_PP~01~01G~G~q_PPSupersymmetry:Standard Model:+Supersymmetric Particles in Final State+No Supersymmetric Particles in Final StateExample Final States: Two photons and SupersymmetrySUSYDavid Toback Sept 200416q_PPStandard Model:_PP~01~01G~G~Supersymmetry:SUSYG~G~susySUSY Particles Leave the detector→Energy ImbalanceSM~01~01No Energy