Latest Physics Results from ALEPH Paolo Azzurri CERN - July 15, 2003.

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Latest Physics Results from ALEPH Paolo Azzurri CERN - July 15, 2003

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  • Latest Physics Results from ALEPH Paolo Azzurri

    CERN - July 15, 2003

    P.Azzurri - Latest physics results from ALEPH

  • Whats new ?

    QCD Studies

    Four fermions & Gauge Couplings

    Jet reconstruction & radiative Z peak

    SUSY searches Conclusions & Prospects

    P.Azzurri - Latest physics results from ALEPH

  • QCD studies

    P.Azzurri - Latest physics results from ALEPH

  • S @ 91-209 GeVNLO + NLL TheoryTheory syst error evaluated with the lepwg method (uncertainty band method)Consistent analysis at all energies using six event shape variablesin hadronic events

    P.Azzurri - Latest physics results from ALEPH

  • Two-dimensional BE correlationsSelection of two-jet events with large thrustqqp2p1String = Pion sourceQ= Dp= p1 - p2QL : longitudinal component of DpQT : transverse component of DpData/MC double ratio of the distribution of like-sign tracks to reference samples

    P.Azzurri - Latest physics results from ALEPH

  • Two-dimensional BE correlationsLund Model predicts RT
  • Rapidity gaps in gluon jetsFrom OPAL proposal to test CR at Z peak

    P.Azzurri - Latest physics results from ALEPH

  • Rapidity gaps in gluon jetsNew ALEPH measurement as a function of the rapidity gap (data-MC)/MC

    P.Azzurri - Latest physics results from ALEPH

  • Four fermions & Gauge Couplings

    P.Azzurri - Latest physics results from ALEPH

  • Zee production New analysis of the hadronic decay channeleeqq: 4f signal defined by lepwg convention

    Selection efficiency=24%, purity =82%

    P.Azzurri - Latest physics results from ALEPH

  • W-pair productionConsistent event selections at all energies 183-207 GeVMore stringent evaluationsof systematic uncertaintiesLatest data reprocessingand event reconstructionsFINAL !

    P.Azzurri - Latest physics results from ALEPH

  • W decay couplingsLepton non-universality

    P.Azzurri - Latest physics results from ALEPH

  • BE correlations in W pairsW pairs Double ratio: four jet decays compared to two mixed hadronic parts of semileptonic decays4q2q2q

    P.Azzurri - Latest physics results from ALEPH

  • BE correlations in W pairsFit double ratio to:unlike sign pairslike sign pairs

    P.Azzurri - Latest physics results from ALEPH

  • BE correlations in W pairsDouble differenceComplementary measurement: like sign pairsunlike sign pairs

    P.Azzurri - Latest physics results from ALEPH

  • Triple Gauge CouplingsNew multi-parameter fits with correct O() treatment in W-pair analysis W pairs, single W and single photonscombined

    P.Azzurri - Latest physics results from ALEPH

  • Generic Triple Gauge Couplingsupdated

    P.Azzurri - Latest physics results from ALEPH

  • Generic Triple Gauge CouplingsT.L.Barklow et al. hep-ph/9704217NEW !

    P.Azzurri - Latest physics results from ALEPH

  • Quartic Gauge CouplingsAnalysis of acoplanar photon pairs with high transverse momentum ( final state)

    P.Azzurri - Latest physics results from ALEPH

  • Jet reconstruction improvements& radiative Z peak

    P.Azzurri - Latest physics results from ALEPH

  • Rescaled di-Jet mass Radiative Z event:Jet angles and jet velocities are the fundamental ingredients ofradiative Z and W mass measurements with kinematic fits

    P.Azzurri - Latest physics results from ALEPH

  • Jet velocity & massLast jet reconstruction(with ECAL cleaning)Z peak jets boost(T>0.8)

    P.Azzurri - Latest physics results from ALEPH

  • Simulation of forward charged tracksLoss of forward tracks in data(nuclear interactions in Vdet material)Year 2000 Z peak hadronic eventsAffects regions with at low polar angle(4% max deficit in forward directions)Deficit parametrized as a functionof the track cos and PT

    Monte Carlo tracks corrected

    P.Azzurri - Latest physics results from ALEPH

  • Radiative Z peakUnbinned likelihood fit to a pdf built with a fit to the MC reference

    P.Azzurri - Latest physics results from ALEPH

  • SUSY searches final results

    P.Azzurri - Latest physics results from ALEPH

  • Constraints on the MSSMImprovement of the selectron searchin the gaugino regionNew scan of low tan with stau mixing(without Higgs constraints)limits on the LSP massCombination of searches for charginos, neutralinos, sleptons, higgs

    P.Azzurri - Latest physics results from ALEPH

  • Limits on the LSP mass with stau mixingLSP limit at 95% CLwith any stau mixing

    P.Azzurri - Latest physics results from ALEPH

  • Conclusions & Prospects

    Searches for new physics completed with the LSP limitsMany Standard Model analyses completed or close to being published ALEPH is coming to an end

    Archiving of ALEPH data and Monte Carlo (~3Tb) for long term analysis completed (June 2003)

    P.Azzurri - Latest physics results from ALEPH

  • Two-dimensional BE correlationsComparison with other LEP experiments

    P.Azzurri - Latest physics results from ALEPH

  • BE correlations in W-pairsFit results without fixing the source radius

    P.Azzurri - Latest physics results from ALEPH

  • Triple Gauge CouplingsW-pairs, single W and single photonscombined

    P.Azzurri - Latest physics results from ALEPH

  • Quartic Gauge Couplings

    P.Azzurri - Latest physics results from ALEPH

  • Jet velocity & massZ peak jets boost(T>0.8)Jet boost (and mass) calibrated !ECAL cleaningwith full egs simulation:Last jet reconstructionwith ECAL cleaning

    P.Azzurri - Latest physics results from ALEPH

  • Radiative Z peakMain effective changes wrt observation large data/MC shift :

    Strict cut on beam background ECAL cleanning in jetsRemoval of low energy neutralsCorrection of forward tracks

    P.Azzurri - Latest physics results from ALEPH

    NLO + NLL (next to leading logarithmic (resummation)) TheoryTheor syst errors evaluated with the lepwg method (uncertainty band method)Consistent analysis at all energies using 6 ev shape variables :T, y23, rho (heavy jet mass), BW, BT (wide and total jet broadening), C parameterStandard Goldhaber parametrization results on source sizes depend strogly on the analysis method such as the reference sampleLund Model predicts RT data shows an effect All MC models w/o CR, tuned at same precision levelOPAL at 1.5 gap with btag (instead of softest jet=gluon) consistent with no-CR MCUniform analysis at all energiesNew processing reconstructionMore stringent evaluations of syst uncertaintiesnearly final results for W-pairs.Update of 2001 results. New reprocessed data & mc. New WW reconstruction. O(alpha) corr.Important for mZ & mW kinematic fits of di-jet masses ! dont confuse the jet mass(=velocity) with the di-jet rescaled massThrust >0.8.Discrepancies with low en photonsRef samples : unlike sign pairs (extra resonance corr) / mixed events pairs (less event kinematical corr) - Care to compare same analysis method between lep experiments. (DLO done before aleph)Consistent reco with W mass analysiswinter 2003 mW reco + syst