October 16, 2006Exploring New Phenomena workshop Exploring New Phenomena at CDF Jane Nachtman (Fermilab) for the CDF collaboration

October 16, 2006Exploring New Phenomena workshop Objective This workshop is about bringing theorists and experimentalists together to focus on maximizing the Tevatron’s discovery potential The experimental talks will briefly summarize searches for new physics at CDF and D0 –To help us think about what is possible and where we should go from here –Looking for theorists’ input! We split the signatures –CDF – photons, jets + MET, hi-pt dileptons –D0 – leptons+jets, multi-leptons, long-lived signatures

October 16, 2006Exploring New Phenomena workshop Overview of my talk Brief CDF and Tevatron intro CDF searches –Signature-based, then applied to models Photons –Applied to GMSB, Extra Dimensions Hi-pt dileptons –Z’, G MET+jet(s) –SUSY, LED –Global, signature-based search of all CDF hi-pt data (Vista+Sleuth)

October 16, 2006Exploring New Phenomena workshop CDF Detector

October 16, 2006Exploring New Phenomena workshop Tevatron Almost 2 fb -1 delivered, ~1.6 fb -1 recorded ( 0.95 – 1.2 fb -1 for analysis, depending on which subsystems are used) 4-8 fb -1 by 2009 The Tevatron’s performance is better than ever!!

October 16, 2006Exploring New Phenomena workshop Signature-based searches at CDF Philosophy – models come and go, but the data should stand on its own Design “simple” searches –No optimization for models  no sophisticated cuts –Attempt to provide general result for theoretical input –Basic result : N expected from SM, N observed –Study kinematic distributions –Publish acceptance functions – plug in your own model Drawback – may not provide maximal sensitivity to a particular model –But may point us in the right direction to look further

October 16, 2006Exploring New Phenomena workshop Signature-based searches for photon+X Inspired by Run I hints –“ee  MET” event –Excess in lepton+photon+MET (16 obs, 7.6 +/- 0.7 exp) Theoretical models suggest these signatures (eg GMSB) Mix-n-match: photons, leptons (e,  ), MET, jets,b-jets

October 16, 2006Exploring New Phenomena workshop Search for photon+lepton+X 2 channels –Photon + lepton(e,  ) + MET –Photon + lepton + lepton + X Look for high-pt leptons, photons, high MET (reduce fakes, SM backgrounds) In 930 pb-1 of data e  +MET  +METl  +MET SM 94  8 54  7148  13 Data ee  +X  +X ll  +X SM 39  5 26  3 65  8 Data SM is W/Z gamma, W+fake No events with extra photons, leptons observed SM is W/Z gamma, W+fake No events with extra photons, leptons,MET observed No e 

October 16, 2006Exploring New Phenomena workshop Check kinematics in l+gamma+MET

October 16, 2006Exploring New Phenomena workshop Diphoton + X searches X = e, , ,MET Backgrounds evaluated from data –Use sidebands – loose photons not passing signal photon selection Dataset = 1 – 1.2 fb -1 gg+X, X= SM Nobs e 3.8 +/  0.7 +/ MET 116 +/  2.2 +/

October 16, 2006Exploring New Phenomena workshop Kinematics in  +X channels Control region Signal region

October 16, 2006Exploring New Phenomena workshop High-mass diphotons high ET (>15) isolated diphoton resonance –Background : QCD diphotons (simulation), jets (from data)

October 16, 2006Exploring New Phenomena workshop Long-lived Exotic particles D0 talk will cover more in detail, just one photon- based search here Several models predict long-lived particles: charged or neutral, decaying inside or outside detector –Charged – look like slow muon (new CDF results soon) or delayed jet –Neutral decay inside detector – delayed photons  CDF analysis decay outside detector – photon + MET  planned analysis

October 16, 2006Exploring New Phenomena workshop Delayed Photon Analysis Relies on EM calorimeter timing detector Measure photon arrival time  backgroundsignal

October 16, 2006Exploring New Phenomena workshop signal region No new physics found here, so far Interpret in GMSB Search for Delayed Photons

October 16, 2006Exploring New Phenomena workshop Signature-based searches for dileptons + X at CDF Look for excess above SM prediction in dilepton +X (X = photon, lepton, b- jet, HT, Missing ET; dileptons can be same-sign or opposite-sign) –Set cuts on first 1/3 rd of dataset,apply to larger dataset –can be further applied to many models; e.g. heavy quarks as first example Dilepton (ee, , e  ) + high H T HT == scalar sum of electron and jet ET, muon pT, missing ET No excess, but one event at HT=900! Good agreement in HT<200 control region.

October 16, 2006Exploring New Phenomena workshop High mass dileptons High ET electrons, optimized to look for high-mass resonances ( GeV) Applied to spin-1 Z’ and spin-2 RS Graviton 19% pe’s have 2E-3

October 16, 2006Exploring New Phenomena workshop Combine limits with diphoton on coupling vs graviton mass in RS model Set limits on SM-like Z’

October 16, 2006Exploring New Phenomena workshop Search for Massive Resonances Decaying to ZZ  eeee Spectacular signature!! Model: RS Gravitons can decay to ZZ,  xBr=292fb (0.66 events expected in 2 fb -1 – not yet sensitive) Signal region M(eeee) GeV

October 16, 2006Exploring New Phenomena workshop Like-Sign dileptons Signature-based search Currently: chargino- neutralino production Basic selection: expect 34+/-4, see 44 Tight selection: expect 8 +/- 1, see 13

October 16, 2006Exploring New Phenomena workshop MET + Jets Signature: monojet events Model: LED (ADD) Graviton production leads to excess (not resonance) Set limits on MD vs N extra dimensions

October 16, 2006Exploring New Phenomena workshop MET + jets in SUSY Search for squarks/gluinos in MET + jets Add flavor tagging for stop/sbottom

October 16, 2006Exploring New Phenomena workshop Vista/Sleuth – the ultimate signature-based search Algorithm to look at Tevatron data globally –Because new physics will probably not show up where we are expecting it –Look in hundreds of final states simultaneously Vista – look at bulk distributions, find compatibility with SM (chi-square fit) Sleuth – look in hi-pt tails –Flag a final state as “interesting” –Show us where to look in more detail Further steps Quaero and Bard…to interpret new physics

October 16, 2006Exploring New Phenomena workshop summary Tevatron searches are going at full steam –Lots of analyses ongoing, new and interesting results coming out –No new physics yet, but we remain hopeful Need to focus our efforts for the full Tevatron dataset –What can we learn from what we’ve already done, to plan for the future? We’ve tried to cover as much as possible, but are we overlooking important signatures, models? Theoretical guidance for our program of Searches for New Physics

October 16, 2006Exploring New Phenomena workshop Backup Slides

October 16, 2006Exploring New Phenomena workshop SM and Other Backgrounds SM Collisions Beam Halo Cosmics Signal Monte Carlo How do I know how each background looks like? Can not use photons. Signal (Blinded) Region 4 sources, all estimated from data Collision photons from SM Right vertex Wrong vertex Non-collision “look-like photons” Beam Halo Cosmics

October 16, 2006Exploring New Phenomena workshop Highest Mass Diphoton Event (604 GeV/c2)

October 16, 2006Exploring New Phenomena workshop Highest Mass Diphoton Event

October 16, 2006Exploring New Phenomena workshop Top dilepton event at HT=900? Leptons: e 28 GeV,  159 GeV Jets : 216 GeV (b-tag) 199 GeV 156 GeV 15 GeV MET: 90 GeV