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CERN, EP division on behalf of the DELPHI collaboration

DELPHI status report. Roberto Chierici. CERN, EP division on behalf of the DELPHI collaboration.  The final data and simulation reprocessing  Status of LEP2 measurements and searches  Status of LEP1 measurements  Outlook. LEP jamboree, 28th February, 2002. v d /v d =10 -4.

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CERN, EP division on behalf of the DELPHI collaboration

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  1. DELPHI status report Roberto Chierici CERN, EP division on behalf of the DELPHI collaboration  The final data and simulation reprocessing  Status of LEP2 measurements and searches  Status of LEP1 measurements  Outlook LEP jamboree, 28th February, 2002

  2. vd/vd=10-4 Final data reprocessing cm/s  New TPC corrections distortions corrected by physical parametrization of defects offline correction of the time dependence of drift velocity  New VD alignment (+detector)  Same tracking code now for all years consistent treatment of data ideal for study of systematics corrected online database Roberto Chierici - DELPHI status report

  3. new/old 5-10% improvement in pure b region b-tagging improvements  The latest reprocessing include new alignment  new tuning of the b-tag at the Z DELPHI Ecm=206.5 GeV Zbb Zqq Check DT/MC agreement on h.e. with an independent sample Check data with data:  ratio of cumulative distributions includes IP, mSV, ESV(ch), ytracks, pT,SV, pT() info Roberto Chierici - DELPHI status report

  4. Final MC setup Big effort for choosing the best setup for our measurements: 2-fermion • Use of KK2f to improve DT/MC agreement • ISR-FSR interference effects to O(2) included • Better treatment of ISR Real 4-fermion LEP2 MC workshop gives us new tools for including O(EM) in CC03 physics (DPA): (RacoonWW, YFSWW) Virtual correction relevant effect (~2%) on WW, d/dW  Review our 4f generation to include DPA without losing other features Roberto Chierici - DELPHI status report

  5. DELPHI strategy for 4f generation (I) Keep the best features of DPA calculations and 4-f generation CC03 issues  inclusion of DPA  non-diagonal CKM  ISR with pT, FSR 4f issues  running of EM  IFL for We  t-channel ISR  low mass qq resonances  efficient integration (access more phase space)    (1S) (2S) m(qq) (GeV) WPHACT*+YFSWW *adapted by DELPHI Roberto Chierici - DELPHI status report

  6. hadronization DELPHI strategy for 4f generation (II) Only WPHACT to exploit the largest phase 4f phase space in an efficient way (only  regions are generated independently)  one shot generation  much looser generation cuts  reweight events to any desired subprocess from YFSWW DPA is included through event weights from YFSWW: 4f wDPA with YFSWW PYTHIA BDKRC TWOGAM  WPHACT |Mi|2/|M4f|2 wTGC |M4f(mW,W)|2 Full simulation production: 175M MC events on tape in ~190 days ! Roberto Chierici - DELPHI status report

  7. LEP2 measurements 2-fermion production heavy flavours mW WW (N)TGC final state interactions 4-fermion non-CC03 ZZ Zee+We Z*  physics WW We  finalising results... Roberto Chierici - DELPHI status report

  8. f1 11 f2 W- e- e+ f3 W+ W 22 f4 Anomalous TGC (I) Test SM predictions for WWZ/WW interactions Assuming C, P, gauge invariance only 3 independent parameters describe deviations from SM: g1z, ,  DELPHI PRELIMINARY  WW and angular variables sensitive to couplings 189 GeV WW(qq)-,+()+,- WW(qiqj)Qjet (qkql)Qjet We qqe, e DPA  =+0.5  =0 (SM) • For preliminary results: • qq - BML fit to cos(W+), cos(-), W+,- • qqqq - EML fit to cos(W-) • Other analysis in progress: • OO nearing completion in qq •  improve final precision  =-0.5 cosW+ Roberto Chierici - DELPHI status report

  9. qqqqqqWe combined Anomalous TGC (II) Preliminary results from all LEP2 data (~700 pb-1: 2400 qq, 5000 qqqq, 300 We) qq PRELIMINARY Systematics error included: bck,detector, fragmentation, theory  0.01 for g1z, , 0.07 for  But still measurement is dominated by statistical errors DPA inclusion has changed the limits by about -0.5(stat+sys) ( most sensitive) No deviations from SM combined Roberto Chierici - DELPHI status report

  10. e- e- Z Z Z e+ e+ Z ZZ production cross-section Test the SM in the 4-f NC sector, check important background to Higgs Measure ZZ like final states, then correct to determine NC02 Final state BR technique backgrounds qqqq 49% fit to likelihood WW, qq() qq 14% cut based WW qq 28% IDA WW, We, qq()   4% cut based WW   1% cut based 4-f non resonant 2000 Systematics: qq modelling (hadronization, gbb), lepton id., detector 1998 All data can be combined to increase precision (energy correlation taken into account): 1999 YFSZZ RZZ=exp/th=0.9 0.08stat 0.02syst (theory error excluded) Roberto Chierici - DELPHI status report

  11. 4EtagEbeamsin2(tag/2) Photon structure function Measure F2(x,Q2) from LEP1 and LEP2 data: 3 GeV2/c4 < Q2 < 2600 GeV2/c4 etag RPC QPM VDM Unfolding procedure: TWOGAM, PHOJET, PYTHIA From Q2, mhad (QPM+VDM+RPC)  major uncertainty from systematics due to data description by simulation  LEP1/LEP2 data consistent with linear behaviour F2log(Q2) Roberto Chierici - DELPHI status report

  12. S-matrix fit to LEP1 and LEP2 data Model independent approach to describe e+e-2f cross sections and asymmetries LEP1+LEP2 data are now used to fit the 16 (8 assuming lepton universality) free parameters Jhadtot f-b(h,e,,),tot (h,e,,) at LEP1 (final) f-b(h,,),tot (h,,) at LEP2 For the first time use all statistics  significant improvement using LEP2 data as well (Z interference information)  Jhad in agreement with SM in a more convincing way mZ(GeV/c2) Roberto Chierici - DELPHI status report

  13. LEP2 searches SM Higgs MSSM Higgs H++ MSSM scan (SUGRA) GMSB SUSY AMSB SUSY RPV Exotica Technicolour FCNC Excited leptons Leptoquarks  finalising results... Roberto Chierici - DELPHI status report

  14. ~ G m ~ ~ Ldecay(NLSP) tag G G ~ eVLdettracks from VTX O(1-102) eV~Ldetkinks, large IP >O(102) eVLdetstable charged particles GMSB (I) is the LSP Ldecay(NLSP) depends upon m PRELIMINARY Roberto Chierici - DELPHI status report

  15. ~ G m < 1eV/c2 GMSB (II) Free parameters: F, , M, n, tan, sign() n=1 determines who is the NLSP n>1 Effective SUSY breaking scale PRELIMINARY (all data combined) Scan in 5D for exclusion combining all channels Excluded regions > 86 GeV/c2 (95% CL) > 17.5 TeV/c2(95% CL) Roberto Chierici - DELPHI status report

  16. > 70 GeV/c2 -95% CL-  > 100 GeV/c2 -95% CL- AMSB Unknown m3/2, tan, m0, sign() Same LSP as in mSUGRA • Use the absence of signals to constrain the parameter space 4D scan ISAJET (no RC) Roberto Chierici - DELPHI status report

  17. RPV searches Study signatures where SUSY particles decays do not conserve either L (ijkLiLjEk) or B (ijkUiDjDk) Production decay LLEUDD gauginos 2,4,6+Emis6q,8q,10q sleptons 4,6+Emis 2+6q stops 2q+4+Emis8q No signal observed at LEP2  set limits from the observed number of events (in general dependent on the model parameters) LLE UDD 40 GeV 38 GeV 103 GeV 102.5 GeV 87 GeV ~85 GeV ~90 GeV - ~87 GeV ~80 GeV Roberto Chierici - DELPHI status report

  18. LEP2, 95% CL PRELIMINARY PRELIMINARY Spontaneous RPV S-RP breaking leads to the presence of a massless Goldstone boson J (LSP) Only breaking in the third family considered (higher Yukawa couplings) Look for Majoron production through dominant BR  two acoplanar  and missing E 72 candidates in 654.6 pb-1 LEP2 data, 72.32.5 expected Roberto Chierici - DELPHI status report

  19. LEP1 2-fermion QCD heavy flavours  physics spectroscopy Roberto Chierici - DELPHI status report

  20.  lifetime Topology Events (91-95) Method 3vs3 2101 ML fit to t=(v-BS)/csinTh 3vs1 15427 ML fit to t=(v-BS)/csinTh 1vs1 26036 (94-95) IP difference: d= csin  miss distance: =d1+d2 Result 3p=(288.62.4stat 1.4syst) fs (291.43.6stat 1.5syst) fs (292.02.3stat 2.1syst) fs (291.82.3stat 1.5syst) fs 36% corr.  LEP1 (1991-1995) 1p=(292.02.3stat 2.1syst) fs Sources of systematics:  parametrisation of resolution functions  VD alignment corrections  background description Combining all results (with correlations): =(290.91.4stat 1.0syst) fs Roberto Chierici - DELPHI status report

  21. Testing lepton universality Using the DELPHI measurements of BRs(): g/g=1.00140.0053 g/ge=0.99960.0046 Under the assumption of e- universality: BRe, =(17.8380.066stat0.068syst)% g/ge,=1.00040.0041  excellent agreement with e-- universality PRELIMINARY Roberto Chierici - DELPHI status report

  22. s(mZ) = (0.1180.003) Helicity structure of fragmentation Aim: independent determination of s NP power corrections perturbative QCD ycut dependence To account for hadronization corrections:  MC correction (model dependent)  Clustering of the data (hadronparton) s(mZ)=(0.1080.001stat 0.012syst) L/tot, renormalization scale, ycut Using non corrected data (hadronization effects in): s(mZ)=(0.1130.001stat 0.012syst) A1=(0.140.06) GeV Roberto Chierici - DELPHI status report

  23. f1 measurements Little known about P-wave mesons like 3P1 and 1P1 PRELIMINARY Study 1++ meson production f1(1285), f1(1420) in: Z  (KSK) + X0 1992-95 id. via RICH, TPC m(KSK)<1.04 GeV +- m = (12744) MeV w = (2912) MeV background subtracted Partial wave analysis: m = (14264) MeV w = (5114) MeV Assuming the f1 BR into KSK the production rate in hadronic decays of the Z is determined: isot. back. f1(1285)/(1295) <n> = 0.1590.051 for the f1(1285) <n> = 0.0510.011 for the f1(1420) f1(1420) 1++ a0(980) 1++ K*(892)K  the values of <n>/(2J+1) agree well with the fact that the two meson constituents are of type uu/dd 1+- K*(892)K Roberto Chierici - DELPHI status report

  24. Overview and perspectives • It has been a year of intense activity for DELPHI: • Prepare at best our final processing of data and simulation • Finalise results and papers • precision LEP2+LEP1 measurements, constraints on SM • limits on new theories • DELPHI now and perspectives: • More than 60 (PhD) students working on DELPHI data • Still ~70 papers to be produced: a lot of physics output on its way  this is what we worked for since we started !!! • Activity will go on for the whole 2003... •  we want to have the best out of our data Roberto Chierici - DELPHI status report

  25. Ebeam from radiative events Determine s'/s from polar angles of fermions in e+e-ff events with  lost in the beam pipe s'/s = x = g(f1, f2) = mZ/s for radiative events Fit the distribution of ECM = s1/2-s1/2(LEP) Main systematic errors: QED modelling 40 MeV Bias correction 48 MeV Aspect ratio 48 MeV ECM = (+0.1510.175stat 0.079syst)GeV PRELIMINARY Roberto Chierici - DELPHI status report

  26. PRELIMINARY Observables (shape means) s(mZ) had. correctionpower corr.RGI+PCpure RGI RGI RGI describes data without need of power corrections for the hadronisation  only 1 parameter (s)  better precision Renormalisation Group Invariance perturbation theory: its prediction are free from renormalisation schemes dependence PCs in RGI seem redundant Roberto Chierici - DELPHI status report

  27. TGC sensitivity to DPA The expected effect of introducing DPA is to decrease limits on TGC by about 0.5-1stat.(study in qqqq channel) PRELIMINARY 1. total cross-section variation 2. changes in angular distribution of Ws qqqq only Fit to data with WPHACT, no DPA Fit to data with WPHACT, DPA Fit to MC without DPA (i.e. the expected shift) Shifts DPA-noDPA for qq channels: MC DT g1Z -0.010-0.009  -0.013-0.008 -0.067-0.057  data consistent with expected behaviour Roberto Chierici - DELPHI status report

  28. TGC evolution in time qq channels All results are stable during the years TPC S6 PRELIMINARY Roberto Chierici - DELPHI status report

  29. 189-209 GeV 95% CL Doubly charged Higgs H appear in several extensions of the SM PRELIMINARY e+e- Z  H++H--  4 leptons gauge bosons other Higgs the less constrained decay is with four s:  look for four low multiplicity jets events at LEP2 Data Expected bck. H++H--(PYTHIA) 1 0.9 40.5% 95% CL  limit @ 206.7 GeV  use likelihood ratio to set limits on the H++ production cross-section m(HL ) > 100.4 GeV/c2 @95% CL m(HR ) > 100.0 GeV/c2 @95% CL 1 candidate Roberto Chierici - DELPHI status report

  30. f1 (continued) Production rate per spin state Measured differential cross-section 3P1 PRELIMINARY PRELIMINARY  compatible with the f1 resonances hypothesis Roberto Chierici - DELPHI status report

  31. DPA weights To account for DPA corrections to CC03: Correction as a weight from YFSWW Khoze-Chapovsky Coulomb screening Background events (ie non-CC03) for which wDPA=1 Large weights!  net effect on total cross section larger than 2% Negative global weights due to uncorrected interference. Corrected afterwards Roberto Chierici - DELPHI status report

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