1 / 25

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,)

remedy
Download Presentation

Search for New Physics with Photons at CDF

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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

More Related