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

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Presentation on theme: "News from DELPHI Analyses W. Adam Institute of High Energy Physics Austrian Academy of Sciences on behalf of the DELPHI collaboration LEP Jamboree, July."— Presentation transcript:

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 ±0.0143± ±0.0032± ±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: )(SM: )

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= GeV 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 = ±0.045 stat ±0.034 syst ± 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’ { "@context": "http://schema.org", "@type": "ImageObject", "contentUrl": "http://images.slideplayer.com/3418346/12/slides/slide_21.jpg", "name": "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 Z and m b’

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 > GeV/c 2 (110.6 expected) gluons: m h > 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= GeV) qq  32 (27.2±0.4)  19 (19.5±1.1) ll  3 (5.0±0.6) m h > 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 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 !!!


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