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GLOBAL ELECTROWEAK FITS AND CONSTRAINTS ON THE HIGGS MASS

GLOBAL ELECTROWEAK FITS AND CONSTRAINTS ON THE HIGGS MASS. Pete Renton University of Oxford LEP Electroweak Working Group. status of precision Z and W boson properties top quark mass, α (M Z ) and other SM parameters agreement of data with SM ?

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GLOBAL ELECTROWEAK FITS AND CONSTRAINTS ON THE HIGGS MASS

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  1. GLOBAL ELECTROWEAK FITS AND CONSTRAINTS ON THE HIGGS MASS Pete Renton University of Oxford LEP Electroweak Working Group • status of precisionZ and W boson properties • top quark mass, α(MZ) and other SM parameters • agreement of data with SM ? • global electroweak fits and Higgs mass new Emphasis on results since EPS Aachen Summer 2003 ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  2. Z - Z boson properties: LEP + SLD results (almost!) final (f=l,c,b) f f (f=c,b) ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  3. CDF D0 19th year! new Run 1improved Mt measurement from D0 ~100 pb-1 new Run 2 prelim Mt measurements from CDF & D0 from ~160 pb-1 combinations (Run 1 only) by Tevatron Electroweak Working Group ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  4. Precision (pseudo-)observables Z lineshape (5) tau polarisation - Ae(1) left-right asymm -Ae (1) Z (b,c) properties (6) Total of 17 at high Q2 (assuming lepton universality) from > 1000 measurements with (correlated) uncertainties W properties (2) top quark mass (1) ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  5. Electroweak Corrections Standard Model parameters: & plus ‘unknown’ top-quark mass ‘predicted’ by electroweak corrections prior to direct discovery 40th anniversary of Peter Higgs’ papers eg LP 1995 Beijing does this work for the Higgs ? new SM: TOPAZ0 and ZFITTER 6.40 sin2θefffermion 2-loop: MW full 2 (& leading 3)-loop ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  6. Z boson LEP lineshape results other measurements lepton couplings derived quantities leptons favour low Higgs mass ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  7. Combined LEP/SLD Z heavy flavour results updates from SLD -all results & combination (almost) final new Z- b (and c) asymmetries favour high Higgs mass (F/B asymmetries are statistics dominated) ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  8. W boson mass Tevatron Run 2:CDF,D0 coming soon! final analyses still in progress LEP2 MW favours low Higgs mass ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  9. W boson width W branching ratios new final results from ALEPH & L3 ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  10. top quark mass: Run 1 new D0: improved Run 1 value ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  11. top quark mass – Run 2 (prelim) CDF new new D0 not yet included in world average ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  12. α(MZ) EWWG default value – ‘data’ driven- no significant change using latest re-analysed CMD-2 and KLOE data (LAPP EXP 2004-4)also use a more ‘theory’ driven value ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  13. long standing (and a-posteriori) observation of difference between: leptons hadrons essentially from difference of prob = 8.4% ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  14. THE BLUEBAND PLOT Global electroweak fit – high Q2 data new Since Aachen EPS Summer 2003 new top mass increases mH by ~20 GeV new 2-loop terms etc increase mH by ~6 GeV Awramik,Czakon,Freitas,Weiglein hep-ph/0311148,0407317 &refs therein Faisst,Kuhn,Seidensticker,Veretin N Phys B665,649(2003) + many more! ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  15. pulls Higgs mass from individual measurements direct search limit ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  16. mt , mw direct vs indirect direct mt and mw indirect mt and mw reasonable degree of overlap powerful test of SM ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  17. progress since Lepton Photon 95 in Beijing 68% cl 2004 direct mt and mw 2004 indirect mt and mw 1995 indirect mt and mw 1995 direct mt and mw ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  18. Atomic Parity Violation (APV) Measurement of weak charge in 133 Cs Q2 ~ 5 10-5 GeV2 (SM -72.93) new Woods et al, Sci. 275 (1997) 1759; Ginges & Flambaum, physics/0309054 Moller scattering new E158 SLAC (prelim) hep-ex/ 0312035, 0403010 & E158 website Q2 ~ .03 GeV2 polarised e- beam – measure right-left parity violating asymm. APV(accuracy ~3 10-8) (SM 0.2310) ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  19. NuTeV experiment Measure R = NC CC SM - Q2 ~ 15 GeV2 for mt = 175, mH = 150 GeV fit also including low Q2 data New physics? : Z’, contact int., lepto-quarks, new fermions, neutrino oscillations . … or old physics ?: pdf’s uncertainties in LO, isospin violation, s-sea asymm., shadowing, QED corrections (hep-ph/0310364) … mH 128 GeV ( +14 GeV) prob of fit  5.4 % pull (NuTeV) = 2.9 ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  20. summary • steady progress on both experiment & theory fronts • although still issues with AFB(b) and NuTeV results (both ~3sigma effects) SM gives satisfactory fit to large amount of data. Clarification desirable – but how & when? • fits favour relatively light Higgs (<260 GeV@95% cl) • current best value is • improved mt and mw values eagerly awaited the future ? What is the Higgs mass? THANKS to the EWWG, especially Martin Grünewald ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  21. what I didn’t have time for ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  22. hadronic couplings of Z results internally consistent ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  23. ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  24. b and c-quark couplings SM for b & c insensitive to variations in mt and mH marginal (~3%) agreement with SM for b-quark (mostly in the r.h. coupling) ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  25. Combined LEP/SLD heavy flavour results ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  26. ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

  27. low Q2 experiments ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004

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