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Ongoing physics analyses and future projects

Ongoing physics analyses and future projects. Véronique Boisvert Marshak Fellow For the CDF Rochester group. Rochester DOE Site visit July 18 th 2006. Focus of the group. Phys. Rev. Lett. 96, 211801 (2006) J. Lee , G. De Lentdecker Already referred to in 3 papers.

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Ongoing physics analyses and future projects

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  1. Ongoing physics analyses and future projects Véronique Boisvert Marshak Fellow For the CDF Rochester group Rochester DOE Site visit July 18th 2006

  2. Focus of the group Phys. Rev. Lett. 96, 211801 (2006) J. Lee, G. De Lentdecker Already referred to in 3 papers Public result for the matrix element method in Lepton+Jets golden channel using 318pb-1 E. Halkiadakis (now Rutgers University professor) • Electroweak interactions as probe of new Physics • W and Z bosons: • W charge asymmetry • Z ds/dy distribution • Z Forward Backward Asymmetry (AFB) • Search for Z’e+e- • Top quark: • Top Mass • Charged Higgs production • Flavor Changing Neutral Currents • Top Charge • Search for new quark states: • Exotic bottom baryon search Analysis completed and received best Rochester undergraduate thesis award G. Yu, S. Field , Y. S. Chung Phys. Rev. Lett. 96, 042003 (2006) R. Eusebi (now FNAL Lederman fellow), A. Hocker (now FNAL scientist) Already referred to in 2 papers New analysis started: G. Yu,Y.S. Chung Legend: Past year Current and future work Plan for public result

  3. B.Y. Han, A. Bodek, Y. S. Chung, E. Halkiadakis, K. McFarland q* q* W Charge Asymmetry • u quark carries higher fraction of proton momentum! • Get constraints on the PDF’s of the proton • Important QCD information • Helps to better model production rapidity of heavy systems (W, Z, tt, etc.) • Reduces systematic uncertainty from acceptance corrections anti-proton direction proton direction • V-A impacts • W production kinematics • W decay kinematics

  4. W Charge Asymmetry • Analysis method: Number of W vs yW • Use MET for Pn: missing Pz! • Use MW constraint to get 2 possible yW • Weight each of them depending on: • Angular distribution • W cross section • Depends on A! • Iterate! • Araw Atrue: Corrections: q(p)+q(p) q(p)+q(p) q(p)+q(p) q(p)+q(p) • QCD Background subtraction from data • Use new technique of fitting e isolation shape • Charge misidentification using Z e+e- data • MET • Acceptance and smearing

  5. W Charge Asymmetry • Systematics: • E scale (ET(e), MET) • PDF uncertainty: • Angular Distribution • W cross section • Background • Material effect, Acceptance • 1fb-1 prediction • Investigating East-West Asymmetry discrepancy • Expect public result with 343pb-1 by end of summer

  6. J.Y Han, A. Bodek, H. Budd, W. Sakumoto, Y. S. Chung ds/dy distribution of the Z boson • Probe high momentum fraction of the proton at high rapidity: • Use Plug-Plug region to reach |y|<2.8! • Analysis uses 850pb-1

  7. ds/dy distribution of the Z boson • QCD background predictions: Isolation fitting method • Use data to get signal and background isolation shape (subtract W+jets from background selection using MC for shape and data for normalization) • Systematics: • Background estimation • Material • Remaining: • 1fb-1 • Electroweak backgrounds • h dependence of ID efficiencies • Already started public result procedure Zcc 0.420.09%  (Zee) : 251.15± 1.04(stat.)0.31(sys.)pb

  8. J. Lee, G. De Lentdecker, K. McFarland Measurement of Z AFB • Dilepton decay of g*/Z has forward backward angular asymmetry • AFB=(NF-NB)/(NF+NB) • Probe V-A nature of weak interaction • New technique:Response Matrix inversion • Rij=P(observed in bin i | true value in bin j) • Observed =R * True • True = R-1 * Observed • True = R-1 * (Observed - bckg)

  9. Measurement of Z AFB • Backgrounds: • QCD backgrounds • New technique: fitting isolation shape using templates: • Electron: data at Z pole • Jets: high pt electron data, remove W/Z events • Electroweak backgrounds: use MC • Systematics: • E scale and resolution, Response matrix, Background, material, PDF • 364pb-1 result already public • Updating with 1fb-1 • Extract coupling constant, sin2qw

  10. J. Lee, G. De Lentdecker, K. McFarland Measurement of Z AFB • Other method: increase sensitivity by fitting cosq* in mass bins • Worry about acceptance, smearing, QED radiation and fit convergence • Backgrounds: • Use tools from matrix inversion method • Systematics: • Use results from matrix inversion method + worry about NLO QCD distorsion of cosq* distribution • Public result with 1fb-1 around end of summer • Fit function minimizing CF and CB

  11. J. Gimmell, U. Husemann, (K. McFarland), P. Tipton, Harvard, UCLA FCNC in the Top sector • FCNC in the SM only allowed by penguins • BR<10-12 • New Physics strongly enhances BR (~10-3-10-4) • MSSM, 2HDM, dynamical EWSB, warped ED, etc. • Looking at tt  Wb Zc • Standard: W jj, Z  ll (dilepton from Z + 4 jets) • Also: W  ln, Z  ll (trilepton + 2 jets + MET)

  12. FCNC in the Top sector • Backgrounds: • Z+jets: use sophisticated Alpgen MC and validate with data distributions • Z + 4 jets • Zbb + ≥ 2 jets • Zcc + ≥ 2 jets • SM Top • Diboson (WZ) • Jets faking leptons • For greater sensitivity separate events according to • ≥ 1 b tag • = 0 b tag • Optimize event selection based on best expected limit (Feldman-Cousins including systematics) Heavy Flavor fraction not well modeled, new: use templates and fit the data to get fraction

  13. V. Boisvert, W. Hopkins (undergrad), M. Schwarz (undergrad),K. McFarland, MSU Top Charge ? • X W+b or W+b (and cc)? • If exotic q=-4/3, better EW fit • hep-ph/9810531, hep-ph/9909537 • Ingredients: • 1) Charge of W • Charge of lepton • 2) Pairing between W and b • Dilepton: M2lb value • L+J: c2 algorithm • 3) Flavor of b jet: JetQ algorithm • Measure dilution in dijet data ? b or b ? b or b ? Reco b Reco b True b True b

  14. Dilution in dijet data: Look at correlation between m and away jet Corrections: Non-b fraction on m side and away jet side Template fitting using data b  c m fraction (MC) B mixing fraction (MC) Extrapolate from dijet to tt Backgrounds: Investigated if backgrounds mimic more SM top or exotic quark Mostly symmetric between SM top and exotic Confidence Limit extraction Using Profile Likelihood method and studied sensitivity of: dilution uncertainty: very sensitive amount of backgrounds: not very sensitive etc. Working hard to get preliminary public result with 1fb-1 by end of summer… PTrel Jet axis b tagged x Soft m x Away Jet b tagged Top Charge

  15. G. Yu, Y.S. Chung, A. Bodek, U. of Chicago Charged Higgs Search from Top decays • In SUSY get 5 Higgs bosons, including H • Direct production is small at Tevatron • Look for ttWb Hb • Low tanb, H cs • Use Top mass c2 fitter • M(Wln)=80.4GeV/c2, unconstrained M(Wjj) • Deciding on b tagging requirements • M(H) resolution improvement using 5th leading jet • Sensitivity studies underway

  16. Conclusion • Rochester members involved in crucial CDF analyses that will • potentially lead to NP discovery! • remain relevant even after the LHC turn on! • Isolation fitting method for the QCD background • Precise W rapidity method • b flavor tagging in high pt environment • Students and post-docs primary authors of complex and challenging projects • New analyses and/or novel techniques! • Rochester scientists and faculty provide the necessary infrastructure to the realization of these analyses and the education of the young members!

  17. Backups

  18. Input data reconstruction measuring asymmetry if no, min( ) F1 Fn the closest asymmetry to data assumed sample new assumed sample No Yes W charge asymmetry s(yW) vs. PDF

  19. Rediscover the Top quark g • Use Top physics to establish techniques: • Cross section • b tagging • Background treatment • What about top charge? • Measure em couplings using ttg(hep-ph/0106341) • R=s(g in t prod)/s(g in t decay) • Irreducible bckg from radiation off q,q’ (not an issue at LHC…) • Tevatron: need 20fb-1 to rule out -4/3 at 95%CL • LHC: need 10fb-1 to measure charge to 10% g g g

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