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Search for New Physics with Photons at CDF

Search for New Physics with Photons at CDF. Sasha Pronko for CDF Collaboration. In This Talk…. Search for Randall-Sundrum gravitons in  channel Signature-based Search in +X channel (X=MET,,e,) Signature-based Search in +l+X channel (l=e,; X=MET,,e,)

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Search for New Physics with Photons at CDF

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  1. Search for New Physics with Photons at CDF Sasha Pronko for CDF Collaboration Sasha Pronko (FNAL), PHENO-07, Madison, WI

  2. In This Talk… • Search for Randall-Sundrum gravitons in  channel • Signature-based Search in +X channel (X=MET,,e,) • Signature-based Search in +l+X channel (l=e,; X=MET,,e,) • Other recent “photon” searches not covered in this talk: • Search for exited muons: *+ • Search for delayed photons (see M. Goncharov’s talk) Sasha Pronko (FNAL), PHENO-07, Madison, WI

  3. Search for RS gravitons with  • Extra dimensions (ED) • Motivated by string theory • Way to solve hierarchy problem • Two primary models • Arkani-Hamed, Dimopolous and Dvali (ADD) • Randall-Sundrum (RS) • Curvature of ED  hierarchy between EWK & Planck scales • ED is “warped” with parameter k curvature & mass of graviton resonances • Signature: high mass peaks in e+e-, +-, … • Analysis • Two central-central (CC) or central-forward (CF) photons • ET>15 GeV; M>30 GeV • Sensitive to any narrow  peak Sasha Pronko (FNAL), PHENO-07, Madison, WI

  4. Search for M peaks • ~1.2 fb-1 of data • No significant MET at high masses • No signs of Cosmic Rays with brem in detector • Background • SM  production (~25%) • NLO DiPhox • Normlized by L • Jets faking photons (~75%) • Mostly hard 0’s • Shape from loose  candidates • Normalized to low mass (30-100) – DiPhox contribution • Highest mass • Central-central M=602 GeV/c2 • Central-forward M=454 GeV/c2 Sasha Pronko (FNAL), PHENO-07, Madison, WI

  5. Limits on RS Graviton Production • Limits • Fit M with DiPhox+expo’s; CC & CF separately; no normalization constraints; binned maximum likelihood • Results • Combined with e+e-: M(G)>875 GeV/c2 for k/Mpl=0.1 •  has larger BR; better acceptance due to spin effects Sasha Pronko (FNAL), PHENO-07, Madison, WI

  6. Why +X? • +X signatures • GMSB: +MET+X • SUGRA: +jets+X • b`b`bb • l*l*ll, q*q*qq • New dynamics • Haa • Rare +X events at Tevatron • Infamous CDF Run I “ee+MET” event • Dominant SM: WW  810-7 events • Total: ~10-6 events • D0 Run II “e+MET” event Sasha Pronko (FNAL), PHENO-07, Madison, WI

  7. Search in +X Channel • Signature-based approach • Generic cuts to reduce background • Trade off: “precision limit””broader scope” • keep in mind GMSB as benchmark • Report backgrounds and acceptances • Study kinematic distributions • X=MET, , , e • Coming soon: X=, b-tag •  signal sample • 2 central photons (strict ID cuts): ET>13 GeV • Purity: ~30% of real  •  control sample (to optimize cuts, study backgrounds) • 2 central photons (relaxed ID); 1 photon must fail strict ID • Purity: ~5% of real  • Same backgrounds as in signal sample Sasha Pronko (FNAL), PHENO-07, Madison, WI

  8. Search in +MET Channel • All backgrounds evaluated from data! • QCD+fake MET • MET resolution model • Jet resolution • Unclustered energy (U.E & M.I.) • e events with real MET (e.g., We) • Select e events • Apply e fake rate • Non-collision • Study out-of-time events MET >50 GeV Bckg: 1.60.3 Data: 4 Sasha Pronko (FNAL), PHENO-07, Madison, WI

  9. Search in +MET Channel: MET>20 HT=ET(pho)+ET(jets)+MET+… Sasha Pronko (FNAL), PHENO-07, Madison, WI

  10. Search in +e, channel • Ele (central & forward): ET>20 GeV • Muon (central): ET>20 GeV • Backgrounds: • Fake lepton or photon (from data) • Z + W (from MC) • No surprises in ~1.1 fb-1 Sasha Pronko (FNAL), PHENO-07, Madison, WI

  11. Search in + Channel • 3rd: ET>13 GeV • QCD Background: • Real ++ (from MC) • +fake (from data) • Bckg: 2.20.6 • Data: 4 Sasha Pronko (FNAL), PHENO-07, Madison, WI

  12. Resonant smuon production? Run I Hint #2: l++X 16 observed vs.7.60.7 expected ~2.7 significance 11 observed vs.4.20.5 expected !!! 5 observed vs.3.40.3 expected Any excess in Run II with ~1 fb-1??? Sasha Pronko (FNAL), PHENO-07, Madison, WI

  13. Signature-based Search in l++X Channel • Search in two channels: • l++MET+X, l=e, ; X=l,  • l+l++X, l=e, ; X=l, , MET L=930 pb-1 Sasha Pronko (FNAL), PHENO-07, Madison, WI

  14. Search in l++MET Channel • Leading backgrounds • W (dominant) • Z • W+jet • No events with extra  or l are observed • No excess! Sasha Pronko (FNAL), PHENO-07, Madison, WI

  15. Search in ll++X Channel • Dominant background: • Z+ • No events with extra l, • No e events • Data consistent with background. Sasha Pronko (FNAL), PHENO-07, Madison, WI

  16. Search in ll++MET Channel • MET>25 GeV • Background: 0.60.1 • Data: 3 events observed Sasha Pronko (FNAL), PHENO-07, Madison, WI

  17. Summary • RS gravitons • M(G)>875 GeV for k/Mpl=0.1 • +X and l++X channels • Run I “hints” are not confirmed with ~1 fb-1 of Run II data (> x10 of data!) • Standard Model prevails • Tevatron is doing great • plenty of opportunities for new physics with 3-8 fb-1 still to come! • Many new results with 2 fb-1 are coming soon… stay tuned! • http://www-cdf.fnal.gov/physics/exotic/exotic.html Sasha Pronko (FNAL), PHENO-07, Madison, WI

  18. Backup slides Sasha Pronko (FNAL), PHENO-07, Madison, WI

  19. CDF detector Sasha Pronko (FNAL), PHENO-07, Madison, WI

  20. Search in +X Channel: photon ID Sasha Pronko (FNAL), PHENO-07, Madison, WI

  21. Search for RS Gravitons with  events Sasha Pronko (FNAL), PHENO-07, Madison, WI

  22. Search in +MET Channel (Control Region) Events with MET>20 HT=ET(pho)+ET(jets)+MET+… Sasha Pronko (FNAL), PHENO-07, Madison, WI

  23. Search in +MET Channel • Data (signal and control samples) agree with background predictions Control Sample Signal Sample Sasha Pronko (FNAL), PHENO-07, Madison, WI

  24. Run 199,148 Event 1,171,816 CDF Run II Preliminary Jet 1 MET 2 Search in +MET Channel • Highest MET event: • MET=165.1 GeV • Pho1 ET=304.6 GeV (largest pho ET) • Pho2 ET=20.3 GeV • Jet ET=143.6 GeV • HT=633.6 GeV (2nd largest HT) • Nvx=1, zvx=-25.6 cm • Event origin (likely): • +q++jet, 2nd  candidate is either 0/ or  from jet • MET is due to fluctuation (~5.5) in jet energy measurement R- view of CDF detector Sasha Pronko (FNAL), PHENO-07, Madison, WI

  25. Search in +e channel Sasha Pronko (FNAL), PHENO-07, Madison, WI

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