1. News from DELPHI Analyses W. Adam Institute of High Energy Physics Austrian Academy of Sciences on behalf of the DELPHI collaboration LEP Jamboree, July 15 th, 2003

2. LEP Jamboree, 15/7/03News from DELPHI Analyses2 Status 51 abstracts sent to EPS03 & LP03 Hadronic physics: 5 Hard QCD: 7 Heavy flavour physics: 7 Physics beyond the SM: 14 Test of the SM: 17 Detector and data handling: 1 14 papers published or accepted for publication since summer ‘02 27 drafts in review 4 at journal 7 at EP 16 in internal review Throughout the talk (unless stated otherwise): results are preliminary limits are at 95%CL *After LEP shutdown This story is purely fictional, and any resemblance to real persons and events is entirely coincidental! © Dargaud We are in the year 3AL*. CERN is entirely occupied by the LHC. Well, not entirely … A few small offices of indomitable LEP physicists still hold out against the invaders …

3. LEP Jamboree, 15/7/03News from DELPHI Analyses3 QCD &  Physics Energy evolution of event shape distributions Open b- and c-production in  collisions  s from event shapes  c formation in 2-photon collisions Hadronic photon structure function Inclusive J/  production in 2-photon collisions Inclusive f 1 production in Z decays Search for  b in 2-photon collisions Masses, lifetimes and production rates of  ± Electron structure function b-quark mass effects in the 4-jet rate Colour reconnection in WW using particle flow and m W estimators Correlations between particles from different W bosons m b at m Z

4. LEP Jamboree, 15/7/03News from DELPHI Analyses4 Open b and c Production in  Collisions Production mechanism: Select b and c events using semi-leptonic decays: identify muons fit p t -spectrum to b,c and light quark components  651 events selected uds normalisation fixed using fit to hadron p t -spectra c normalisation fixed according to LEP2 average  (ee  eeccX) directresolved  (ee  eebbX) = 14.9 ± 3.3 stat ± 3.4 syst pb

5. LEP Jamboree, 15/7/03News from DELPHI Analyses5 Open b and c Production in  … (2) First time: use identified K to tag heavy quark flavour b  like-sign K /   (149 events) c  unlike-sign K /   (171 events) Fit c-fraction in unlike-sign sample: Fit to like-sign sample consistent with previous result on b-production DELPHI results confirm excess in observed b-production w.r.t. prediction  (ee  eeccX) = 937 ± 191 stat ± 206 syst pb

6. LEP Jamboree, 15/7/03News from DELPHI Analyses6 Some other  Results Inclusive J/  production in  collisions J/    +  - : selected 36 ± 7 events  c (2980) formation in  collisions Observed:  c  K S K , KKKK, KK  Not observed:  c   Fits to mass spectrum,  tot and  c BRs  radiative width from observed channels: Recently CLEO, E835 and L3 have measured lower values of  .  (J/  +X) = 45 ± 9 stat ±17 syst pb Estimated fraction from resolved  : 74 ± 22 % pT2pT2   = 13.9±2.0 stat ±1.4 syst ±2.7 BR keV

7. LEP Jamboree, 15/7/03News from DELPHI Analyses7 Heavy Flavours b-decays to wrong- signed charmed mesons Excited b-hadron states Moments of inclusive spectra in semileptonic B decays B 0 s oscillations using high-p t leptons  lifetime  b form factor Branching fractions of b into neutral/charged b-hadrons Precise measurement of b-hadron lifetimes V cb using semi-leptonic decays to D*l B 0 oscillations with incl. reconstructed vertex b-hadron production rates and decay properties  hadronic BRs

8. LEP Jamboree, 15/7/03News from DELPHI Analyses8 EW Measurements  (  ) cross section WW  cross section and anomalous QGCs A b FB using inclusive charge reconstruction ZZ production Single vector boson production  -pair production in  collisions WW production cross section and BRs Mass and width of the W boson W polarisations Charged TGCs A c,b FB using prompt leptons Precision EW measurements at the Z resonance Z  * production

9. LEP Jamboree, 15/7/03News from DELPHI Analyses9 A b FB by Inclusive Charge Reconstruction observed numbers asymmetry * relative sign up- / down-like New method: enhanced impact parameter tag for event selection neural networks for charge (b / anti-b) tagging / hemisphere A b FB to be extracted from 2 categories of charge tagged events: single tag (N S fwd,N S bwd ) unlike-sign double tag (N D fwd,N D bwd ) For each category: Highest precision DELPHI A b FB analysis self calibration of key quantities extensive study of systematics uses also LEP1 off-peak and LEP2 Z 0 runs Asymmetry calculated as function of b-purity polar angle of thrust axis year of data taking  allows for precise self-calibration control of data  MC check for consistency

10. LEP Jamboree, 15/7/03News from DELPHI Analyses10 A b FB by Inclusive Charge Reconstruction (2) Enhanced b-tag uses impact parameters & rapidities decay vertex information Efficiencies from data:  b,  c from # single / double tags correlations and  uds from MC Calibration in two steps Careful tuning of resolutions in MC for each year of data taking Correction of b-tag values in MC for c- and b-quarks, based on measured  (b-tag) fraction of events / flavour Integrated event tag: data / MC after correction c-efficiencies vs. hemisphere tag (data, MC) ±1%

11. LEP Jamboree, 15/7/03News from DELPHI Analyses11 A b FB by Inclusive Charge Reconstruction (3) Inclusive charge tagging / hemisphere: Neural Network using estimated charge / B-hadron type from probability / track probability for each B-hadron type jet charge & decay vertex charge Self-calibration from data (number of double-tagged like / unlike-sign events) hemisphere correlation & background correction from MC c charge assignment using MC + calibration from fully reconstr. D*s dilution factor (charge assignment probability) charge assignment probability D* data/MC MC: correlations vs. cut

12. LEP Jamboree, 15/7/03News from DELPHI Analyses12 A b FB by Inclusive Charge Reconstruction (4) Result from simultaneous fit to A FB and b charge assignment probability inputs: “fwd” and “bwd” single and double tags + like-sign tags Pole asymmetry Main contributions to systematics: hemisphere charge correlations c and uds charge identification QCD correction detector resolution √s (GeV) A FB stat. syst. 89.4490.0637±0.0143±0.0017 92.2310.0958±0.0032±0.0014 92.9900.1041±0.0115±0.0024

13. LEP Jamboree, 15/7/03News from DELPHI Analyses13 A b,c FB with prompt leptons & combination Method using high p T & p L leptons (e,  ) to select semi-leptonic b- and c-decays Inputs for b/c/background likelihoods p T & p L, b-tag and charge information (lepton and opposite hemisphere jet) Asymmetries extracted by binned  2 fit to  thrust and likelihoods. Pole values: Combination of DELPHI A b,c FB measurements (SM: 0.1036)(SM: 0.0740)

14. LEP Jamboree, 15/7/03News from DELPHI Analyses14 W-polarisation in e + e -  W + W - Use decay angles as analyser: Extract spin density matrix elements using proj. operators  W±  ’ (  *,  * ) : Assume CP-conservation:  W-  ’ =  W+ -  -  ’ Im  W-  ’ = 0 Data sample: e qq’,  qq’ selected by iterative discr. analysis for √s=189-208GeV 1880 events selected Before extraction of SDM elements events were weighted to account for efficiency (typ. 70%) purity (typ. 92%) and migration (typ. angular resolution 0.05 in cos  W, cos  * ; 80mrad in  * ) as f(cos  W,cos  *,  * )  need leptonic decays  *,  * in W- restframe

15. LEP Jamboree, 15/7/03News from DELPHI Analyses15 W-polarisation in e + e -  W + W - (2) SDM elements agree well with SM prediction (WPHACT):  00  differential production cross section for W L : averaged over e,  and using both W - and W +

16. LEP Jamboree, 15/7/03News from DELPHI Analyses16 Single W production We final states receive contributions from single W, W-pair and Zee. Total cross section: (assume lepton universality,   =   ) Need signal definition: all t-channel diagrams, + W  e  : |cos(  e1 )| 0.95 W  l  (l=e,  )  : E(l) > 20 GeV W  qq’ : M(qq’) > 45 GeV/c 2 Ratio to SM / channel:

17. LEP Jamboree, 15/7/03News from DELPHI Analyses17 Z  * Production Channels: eeqq,  qq, qq 4 charged leptons 4 quarks “Matrix Element” signal definition |cos  f |<0.98  4 fermions weight events by |M Z  * | 2 /|M all | 2 Final selection in bins in M ff -M f’f’ plane “LEP” signal definition: cuts on production angle di-fermion masses compatibility with Z-mass

18. LEP Jamboree, 15/7/03News from DELPHI Analyses18 Method: relation of densities for single-W and W-pairs (assume no correlation): measure for deviation: difference (  ) or ratio (D) of left- / right-hand expression reference: MC predictions with LUBOEI within one (BE ins ) / two (BE full ) Ws For background subtraction: MC with BEC tuned on signal like Z 0 Bose-Einstein Correlations in WW events Fully hadronic WW events Semi-leptonic WW events Mixed hadronic decays from two semi-leptonic WW events: rotated / mirrored to balance momentum

19. LEP Jamboree, 15/7/03News from DELPHI Analyses19 Bose-Einstein Correlations in WW … (2) Statistical aspects: bins in  correlated (multiple entries!) described by covariance matrix propagated to derived quantity D Most pairs within one W: use  -factor & opening angle as additional discriminants reweight pairs acc. to purity Fixing R to BE full model: D(Q): like- sign pairs Fit D(Q)=N(1+  e -RQ )(1+  Q) R(fm)  Data BE full

20. LEP Jamboree, 15/7/03News from DELPHI Analyses20 M W - Contributions to Systematics Detailed studies are underway to verify that no ALEPH-like cleaning is needed. Summary (work in progress): Electrons Under control from the start of LEP2 No corrections Soft energy flow Complicated detailed studies. Fragmentation Large (well known) discrepancies No problem for M W Detector effects Small discrepancies for low energy clusters Estimated impact order of 10MeV Efforts concentrated around soft hadronic energy flow: charged energy flow Discrepancies related to simulation of fragmentation - negligible impact neutral energy flow Small differences seen, possibly due to detector effects Final numbers and implementation of a possible correction expected in the nearest future. Reminder: valid DELPHI number is m W = 80.401 ±0.045 stat ±0.034 syst ± 0.029 FSI ±0.017 LEP GeV/c 2

21. LEP Jamboree, 15/7/03News from DELPHI Analyses21 Searches: SUSY & Exotica SUSY with light gravitino and sleptons as NLSP LSP gluino Search for SUSY and interpretation in MSSM 4 th generation b’ quark Anomaly mediated SUSY breaking SUSY with R p -violation Single top via FCNC  +E miss Spontaneous R p -violation Search for resonant sneutrino production

22. LEP Jamboree, 15/7/03News from DELPHI Analyses22 Search for 4 th generation b’ quark Heavy 4 th generation not excluded  model with additional doublet (t’,b’) If m b’ >m Z and m b’ <m t’,m t,m h : dominant decays to cW and bZ investigate 96<m b’ <103 GeV/c 2 Final states FCNC (∑BR≈81%): ZZ  2 l + 2 ZZ  2 j + 2 ZZ  4 j Final states CC (∑BR≈90%): WW  2 j + l WW  4 j Limits on branching rations (using SM- like  for decay to heavy quarks)

23. LEP Jamboree, 15/7/03News from DELPHI Analyses23 Search for 4 th generation b’ quark (2) Interpretation within sequential model & extended CKM matrix assume matrix real, ≈symmetric, ≈diagonal  BRs = f(m b’,m t’,R CKM ) with R CKM =|V cb’ /(V tb’ V tb )| limits on CKM element ratio for two m t ’ -m b’ cases at limits of allowed range lower limit from FCNC BRsupper limit from CC BRs

24. LEP Jamboree, 15/7/03News from DELPHI Analyses24 Searches: Higgs Doubly charged Higgs Neutral Higgs in MSSM benchmark scenarios Flavour independent neutral Higgs searches Fermiophobic Higgs Limits on m H and tan  from a MSSM parameter scan Charged Higgs in general 2HDM Neutral Higgs in extended models Invisible Higgs Neutral Higgs (SM and MSSM)

25. LEP Jamboree, 15/7/03News from DELPHI Analyses25 Extended MSSM neutral Higgs results Use all DELPHI results consistently Include contribution of H Interpretation in 3 std. benchmarks: m h max, no mixing, large  using partial 2-loop calculations and m top =174.3GeV/c 2 Scan: basic grid: 1GeV/c 2 (m A )x0.1(tan  ) low m A :.02,.1,.25,.5, 1.5, 3GeV/c 2 New LEP1 only limits m h max, no mixing: Small unexcluded region at low m A and m h and tan  ≈10: covered by limit on  Z new. m h > 44.6GeV/c 2 (any tan  ) m A > 44.4GeV/c 2 (tan  >1.7) hZ hA cascades LEP1

26. LEP Jamboree, 15/7/03News from DELPHI Analyses26 Extended MSSM neutral Higgs … (2) m h max no mixing mhmh > 89.7 GeV/c 2 > 92.0 GeV/c 2 mAmA > 90.5 GeV/c 2 > 93.0 GeV/c 2 (tan  > 0.4)(tan  > 0.8) Limit depends strongly on m top m h max no mixing large  Exclusion including H

27. LEP Jamboree, 15/7/03News from DELPHI Analyses27 Flavour-Independent Search for h,A Strategy: design general search for Higgs boson  hadrons reference samples: decays to gluons, light & heavy quarks for flavour-independent results take most conservative assumption at each test point Competing effects: hZm<40GeV/c 2 m>40GeV/c 2 4 jets“3-jet” like probabilistic 4-jet analysis 2 jet + E miss “monojet” like IDA in 3 mass bins 2 jet+ee/  sequential hA “4 jets”High mass, m h ≈m A “3 jets” high  m or low masses “high thrust”both m < ≈40GeV/c 2 gluonslight quarks efficiency  mass resolution arb. norm.

28. LEP Jamboree, 15/7/03News from DELPHI Analyses28 Flavour-independent Search for … (2) Limits in terms of C 2 =  /  (SM) For individual flavours: strange quarks: m h > 108.0 GeV/c 2 (110.6 expected) gluons: m h > 109.2 GeV/c 2 (111.0 expected) Limits in terms of C 2 (=1 for max.  allowed by EWSB)

29. LEP Jamboree, 15/7/03News from DELPHI Analyses29 Search for a fermiophobic Higgs General 2HDM h can decouple from fermions can decay to pairs of Higgs or gauge bosons high BR   in large parts of parameter space details depend on choice of potential describing H-H-couplings Assuming SM + no couplings to ff: hZ channel #events (√s=183-209GeV) qq  32 (27.2±0.4)  19 (19.5±1.1) ll  3 (5.0±0.6) m h > 104.1 GeV/c 2 (expected: 104.6)

30. LEP Jamboree, 15/7/03News from DELPHI Analyses30 Search for a fermiophobic Higgs (2) hA production: searched for hA   bb hA  hhZ   qq excluded by hZ excluded by hA m h limit for mA=115 mainly h  , A  hZ mainly h  , A  bb mainly h , A  bb

31. LEP Jamboree, 15/7/03News from DELPHI Analyses31 Conclusions Physics output: 14 publications since summer 2002 27 drafts in pipeline work in progress on ~ 25 other subjects DELPHI is still a highly active collaboration! Emphasis now on getting remaining analyses quickly to publication stage: many DELPHI members started second activity tends to slow down reviewing process You may expect many new final results at the next LEP jamboree !!!