1 / 19

Physics Beyond the Standard Model with Photonic Final States at CDF

This presentation discusses the search for new physics beyond the standard model using photonic final states at CDF, including searches for LED, anomalous photon+lepton production, and photon+heavy flavor production.

caleba
Télécharger la présentation

Physics Beyond the Standard Model with Photonic Final States 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. Physics Beyond the Standard Model with Photonic Final States at CDF Beate Heinemann University of Liverpool For the CDF collaboration EPS 2003, Aachen, 17.-23.7.2003

  2. / / / ET ET ET Exotics Searches with Photons in CDF Run II The CDF event: eegg 10-6 events expected! The CDF event: eegg • CDF at Run 2 • Search for LEDinDi-Photon Production • Search for AnomalousPhoton+Lepton Production • Search for GMSBwith Di-Photon+ • Search for Photon + Heavy FlavourProduction • Search for LED with Photon+ • Anomalous Couplings: W/Z+Photon EPS 2003, Beate Heinemann, University of Liverpool

  3. New for Run 2 Tracking System Silicon Vertex detector (SVX II) Intermediate silicon layers (ISL) Central Outer tracker (COT) Scintillating tile forward calorimeter Intermediate muon detectors Time-Of-Flight system Front-end electronics (132 ns) Trigger System (pipelined) DAQ system The CDF 2 Detector Retained from Run 1 • Solenoidal magnet (1.4 Tesla) • Central Calorimeters • Central Muon Detectors EPS 2003, Beate Heinemann, University of Liverpool

  4. CDF Run 2 Luminosity ~ commissioning physics Integrated Luminosity pb-1 ~280 pb-1 delivered ~220 pb-1 recorded Run 1b (1994-1996) 08/2001 07/2003 Physics Analyses use about 80 pb-1 recorded up to Jan 2003 (about twice as much good quality data on tape since) Data taking efficiency about 90% now EPS 2003, Beate Heinemann, University of Liverpool 90% efficiency Data Recording Efficiency

  5. Identification of Photon Signals in CDF Photon candidates: Isolated electromagnetic showers in the calorimeter, with no charged tracks pointing at the calorimeter cluster Central EM Calorimeter • Signals • Backgrounds • Two techniques for • determination of photon signals; • 1. EM Shower width (shape): • using Shower Max. Detector • 2. Probability of Conversion: • using pre-radiator hits • Statistical background subtraction   0  Pre-shower Detector Shower Maximum Detector e.g. for diphoton candidates, S/B result using CPR method is.. EPS 2003, Beate Heinemann, University of Liverpool

  6. Di-Photon Mass Spectrum • Search Selection: • 2 photons with Et>13 GeV, cosmic and beam-halo rejection cuts • Main backgrounds: • fakes from photon-jet and jet-jet: determined from data! • Results:1365(95)events for Et>13(25) GeV Mgg=168GeV For M > 150 GeV Expected background: 3.3 Observed: 2.0 Run I Results (LED Search) observed: 287(192) CC(CP) events 95% C.L. Limits on eff. string scale: using a maximum likelihood fit method NO excess observed @ High invariant mass, good agreement b/w Run II Data and expectation For M > 150 GeV Expected background: 4.5  0.6 Observed: 5 95 % C.L. MS > 899 / 815 GeV KLED = 1.0 ( = -1/+1, Hewett) EPS 2003, Beate Heinemann, University of Liverpool

  7. gg+Jets and gg+Leptons Search • Search for gg + X; X=jet(s) • To search for anomalous production of quarks and gluons, look in anomalous Njet production in gg data Result consistent with SM • Search for gg + X; X=lepton(s) • Search Selection:Diphoton+extra lepton(s) • Main backgrounds: • W/Z+, fake , Z,e()+jet No event found Good agreement of Run II data with expectation.. EPS 2003, Beate Heinemann, University of Liverpool

  8. / ET Search GMSB for gg+ • Gravitino is the LSP • NLSP: Neutralino c1 G • Experimental Signature: +ET Missing Et Spectrum pp → c1c1 + X → ggGG + X SUSY would show up as an excess of events with large Missing Energy Run 1: eeggEt • Search Selection: • 2 central photons w/ Et>13(25) • Cosmic/beam halo clean-up • Main backgrounds:(see plot) • QCD diphoton, • jet mis-ID, W+photon (lost track) • Results: • 1392(97)events for Et>13(25) For Missing Et>25GeV Expected background: 22 Observed: 2 Set cross section limit EPS 2003, Beate Heinemann, University of Liverpool

  9. / ET Search GMSB for gg+ (II) Acceptance Events Expected Set the lower mass limit on the lightest chargino in GMSB: Mc>113 GeV @ 95% C.L. EPS 2003, Beate Heinemann, University of Liverpool

  10. B+g: Motivation • Topological search sensitive to “new physics” • Require photon and b-jet • Can look form, e, t, jets in addition • Search originally motivated by Run 1 eeggMEt event • E.g in MSSM: chargino + neutralinoc+ic02 c02->gc01, c+1->c01tb 2b-jets, photon, lepton, missing Et Mass at sec. Vertex: separate b-, c- and light quarks EPS 2003, Beate Heinemann, University of Liverpool

  11. Photon + b-jet: A first look • Cross Sections: • b-g: 40.6±19.4(stat.) ± 7.6(syst.) pb, LO: 68.6 pb • c-g: 486 ± 153(stat.) ± 88 (syst.) pb, LO: 368.4 pb • Data agree with LO QCD predictions • More excl. Searches and Limits on New Physics soon Mass @ sec. vertex Missing Et /GeV B-jet-γ-Mass/GeV EPS 2003, Beate Heinemann, University of Liverpool

  12. qqGKK / ET Search for New Physics ing+ Extra Dimensions Search Selection: - one  with ET > 47 GeV and ||<1 - Missing ET > 42 GeV - No jets with ET > 10 GeV - No tracks with pT > 5 GeV (84 pb-1 ) ADD Main backgrounds: Randall-Sundrum Results: No excess was found Expected background: 18.0  2.1 Observed: 17 95% C.L. upper limit on (accep. x eff. x cross-section) of 121 fb was set Run I limit: MS>0.58 TeV EPS 2003, Beate Heinemann, University of Liverpool

  13. New Physics in Wg Production? • Sensitive to TGC (Dk, l): e.g. compositeness of W/Z • Run I: excess at high Et: lepton Et>25 GeV, Met>25 GeV, photon Et>25 GeV Dk, l EPS 2003, Beate Heinemann, University of Liverpool

  14. Wg Production • s-channel diagram not present in SM • Signature: high pT lepton(e/m) + g, MET>25, photon Et>7 GeV, R(-l)>0.7 • Results: No excess was found • Data: 43(38) • Signal MC+Background : 46.6  1.3  4.5 • (36.5  0.7  3.0) … derived the cross section for Et(g)>7, DR>0.7 Results consistent with SM SM: •B(Wl) = 18.7 ± 1.3 pb EPS 2003, Beate Heinemann, University of Liverpool

  15. Zg Production • Signature: two high pT lepton(e/m) + g • (R(-l)>0.7) • Results: No excess was found • Data: 11(14) • Signal MC+BGD : 10.8  0.9  0.6 • (12.4  1.2  0.7) 3-body mass cross-section for Et(g)>7, DR>0.7 Photon Et Results consistent with SM SM: •B(Zll) = 5.4 ± 0.4 pb EPS 2003, Beate Heinemann, University of Liverpool

  16. Conclusions • CDF is taking high quality data in Run 2 • Run 2 statistics about twice of Run 1 • Covering broad range for photon searches: • Model independent, LED, SUSY,… • No evidence of new physics found • Nothing like run 1 event found yet … but if mother nature gives it to us we will for sure find it! EPS 2003, Beate Heinemann, University of Liverpool

  17. Backup Slides

  18. Di-Photon Mass Spectrum • Search Selection: • 2 central photons with Et>13(25) • Cosmic and beam halo clean-up • Results:1365 events for Et>13 GeV • Classic LHC higgs search channel • SM higgs cross section factor 100 too low for TeVatron, but e.g. boso-philic higgs • Model independent search for “bump” in di-photon mass spectrum • No Signal, limits soon RUN 2 EPS 2003, Beate Heinemann, University of Liverpool

  19. Search for Excited Electrons • Search for the production of excited or exotic electrons (e*) in : • resonance in e invariant mass in eeg events: • select two high pT electrons + one photon (Et>25 GeV) • 0 event observed:setmass limit on e*for contact interaction model:For Me* = Λ, the mass limit is785 GeV M(e*)<785 GeV Λ = Compositeness Scale Since cross-section depends on Me* & Λ, we obtain exclusion region using various values of Me* and Λ EPS 2003, Beate Heinemann, University of Liverpool

More Related