ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004 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 ?  global electroweak fits and Higgs mass Emphasis on new results since EPS Aachen Summer 2003

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

ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004 CDFD0 new Run 1 improved M t measurement from D0 ~100 pb-1 Run 2 prelim M t measurements from CDF & D0 from ~160 pb -1 new combinations (Run 1 only) by Tevatron Electroweak Working Group 19th year!

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

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

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

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

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

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

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

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

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

ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004 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 THE BLUE BAND PLOT Global electroweak fit – high Q 2 data Since Aachen EPS Summer 2003 new top mass increases m H by ~20 GeV new 2-loop terms etc increase m H by ~6 GeV new Awramik,Czakon,Freitas,Weiglein hep-ph/ , &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 Higgs mass from individual measurements pulls direct search limit

ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004 m t, m w direct vs indirect direct m t and m w indirect m t and m w reasonable degree of overlap powerful test of SM

ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004 progress since Lepton Photon 95 in Beijing 2004 indirect m t and m w 2004 direct m t and m w 1995 direct m t and m w 1995 indirect m t and m w 68% cl

ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004 Moller scattering E158 SLAC polarised e - beam – measure right-left parity violating asymm. A PV (accuracy ~ ) Atomic Parity Violation (APV) (SM ) Woods et al, Sci. 275 (1997) 1759; Ginges & Flambaum, physics/ Measurement of weak charge in 133 Cs hep-ex/ , & E158 website Q2 ~.03 GeV 2 (prelim) Q 2 ~ GeV 2 new (SM ) new

ICHEP04 Beijing Global Electroweak fits and constraints on the Higgs mass Pete Renton Aug 2004 NuTeV experiment Measure R = NC CC - Q 2 ~ 15 GeV 2 for m t = 175, m H = 150 GeV 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/ ) … fit also including low Q 2 data SM m H  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 summary  steady progress on both experiment & theory fronts  although still issues with A FB (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 cl)  current best value is  improved m t and m w values eagerly awaited THANKS to the EWWG, especially Martin Grünewald What is the Higgs mass? the future ?

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

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

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

b and c-quark couplings marginal (~3%) agreement with SM for b-quark (mostly in the r.h. coupling) SM for b & c insensitive to variations in m t and m H

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

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

low Q 2 experiments