ch/~bdl/lepc/lepc.ppt1 ALEPH in 1999 Alain Blondel, Ecole Polytechnique zData quality at GeV zLEPI reprocessing finished! zStandard processes are still there: 2-fermion and QCD, WW zanything new? yHiggs ySupersymmetry
ch/~bdl/lepc/lepc.ppt2 Z GeV ALEPH data zALEPH efficiency: 95.6% z 93.3% of delivered pb -1 used for analysis
ch/~bdl/lepc/lepc.ppt3 Tracking Beam loss on 27 July => large TPC distortion -- seen on-line Z run beg. August => understand and correct Short in TPC field cage, causes distortions, can be corrected using Z data + Maxwell&Langevin eqns. Impact parameter (sum d0) of Bhabhas at LEPII Run number--> microns
ch/~bdl/lepc/lepc.ppt4 Tracking Drift in impact params continues, will need to be fixed using Z run in october. Requires reprocessing, not available for the data presented today => slightly worse tracking and b-tagging for GeV data WILL REQUIRE OPENING TPC during winter shut-down!
ch/~bdl/lepc/lepc.ppt5 B-tagging VDET 100% operational all year!.Additional smearing necessary to get good agreement data/MC. udsc bkg in 4b evts underestimated: 5( )-10%( ). will be improved by reprocessing e.g.: hA(bbbb) preselection: b jets udsc jets ALEPH preliminary udsc jets b jets ww qq zz hA
ch/~bdl/lepc/lepc.ppt6 Reprocessing of LEPI data and MC now finished Many analyses going on. preliminary results produced so far with reprocessed data: - s (Vancouver98) - B 0 /B + lifetimes (Moriond99) - AFB(b) AFB(c) (Tampere99) - Leptonic decays of the D s (Tampere99) - Inclusive searches for CP violation (Tampere99) - Today’s special: CP asymmetry in B -> J/ K s
ch/~bdl/lepc/lepc.ppt7 CP asymmetry in B -> J/ K s Select J/ ->ee, K s -> + - 23events/6.4 bkg Measure lifetime, tag charge at production: jet charges, kaon, vertex and lepton charge P(B)= 1 - P(B) at production - Proper time A CP (t ) =-sin(2 sin ( m b t) sin(2 ALEPH conf B B 8 events 15 events
ch/~bdl/lepc/lepc.ppt8 B -> J/ K s event ALEPH conf
ch/~bdl/lepc/lepc.ppt9 CP asymmetry in B ->J/ K s Compare/combine with CDF and OPAL: sin(2 sin(2 at 98.5%CL (CDF alone 93%CL) ALEPH conf
ch/~bdl/lepc/lepc.ppt10 FIRST LOOK AT 1999 data: General features z VERY preliminary results zreprocessing and MUCH MORE UNDERSTANDING needed before data can be presented at conferences ! zanalysis of ~229 pb -1 (Higgs: 237pb -1 i.e. everything -> Yesterday!(8/11/99)) zAll limits are at 95% CL Analyses procedures and cuts defined BEFORE DATA TAKING
ch/~bdl/lepc/lepc.ppt11 Multihadronic events s (m Z )= from LEPII data
ch/~bdl/lepc/lepc.ppt12 Multihadronics = at 202 GeV
ch/~bdl/lepc/lepc.ppt13 multihadrons
ch/~bdl/lepc/lepc.ppt14 2-fermion processes Precision becomes interesting! Th. Error on Bhabha x-section 2%
ch/~bdl/lepc/lepc.ppt15 2-fermion processes
ch/~bdl/lepc/lepc.ppt16 FCNC Single top production 1998 Results Observed18 (16 bcqq; 2 bcl ) Expected 11.5 (10.5 bcqq; 1 bcl ) P(exp = 11.5; obs 18) = 4.6% Small excess (Not seen by DELPHI) 1999 Results: Cand 2.1 exp Cand 11.0 exp Cand 10.0 exp Cand 3.2 exp Tot 30 Cand 26.3 exp 1999 Results: Cand 2.1 exp Cand 11.0 exp Cand 10.0 exp Cand 3.2 exp Tot 30 Cand 26.3 exp Last year excess not confirmed ! Last year excess not confirmed !
ch/~bdl/lepc/lepc.ppt17 WW and ZZ production W branching ratios with all LEPII data: Br (W->e ) = ( )% Br (W-> ) = ( )% Br (W-> ) = ( )% Br (W->qq’) = ( )% SM: 10.83%;67.5% cross-sections low ( )% wrt theory. Jadach et al hep-ph/ , Dittmaier et al hep-ph/ : non-universal corrections => ~ - (1-2)%
ch/~bdl/lepc/lepc.ppt18 Mass resolution WW->qqqq WW->lvqq WW-> vqq ZZ->llqq
ch/~bdl/lepc/lepc.ppt19 HIGGS BOSON SEARCH So, I have heard a Higgs rumor -- six or seven four jet events at Aleph with $b$'s, one background expected. Are you willing to comment? (Would be consistent with about 105 GeV). Regards > > So our friends here on Aleph say they have 7 "Higgs candidate" (4j, 6 with > displaced vertices) events at > mh=~104 in the 200 GeV data, guesstimated background of 1. Have you heard > anything? > subject: ALEPH has discovered Higgs at 105 GeV: please comment Date: Fri, 1 Oct :04: (METDST) Hi, Greetings from DESY. Rumour here (somebody from FNAL, who had heard it from SLAC,...) is that you have found the Higgs. Any comments? Cheers, Hi! Everybody here at CERN is talking about the Higgs discovery by ALEPH. But nobody knows anything quantitative (at least I did not hear anything). May I know as an old XXXXXXX about the evidence? Sincerely, > Su un argomento completamente diverso, c'e' una > voce che corre negli USA (all'Universita' Johns > Hopkins) che ALEPH avrebbe gia' un certo numero > di eventi Higgs ben piu' alto del numero di eventi > di fondo irriducibile che ci si aspetta. > > E' vero? > > Grazie. Cordialmente, Subject: press release? Date: Tue, 2 Nov :22: (Eastern Standard Time) So when is CERN having a press release announcing the Higgs boson discovery? What's the mass? Rumors abound over here, and everyone is sure the silence means it's true. Best, G
ch/~bdl/lepc/lepc.ppt20 Neutral Higgs boson search e+e- -> hZ; hA -Analysis is straight extrapolation of 189 GeV analysis run online, defined before data taking. -possible underestimate (5-10%) of udsc bkg due to b-tagging =>(slightly) conservative limit, (slightly) optimistic signal if any. All search channels investigated: hZ-> bbqq hZ-> bb hZ-> bbll hZ,hA->bbbb, bb qq treatment of overlaps by and/exclusives. Two streams of analyses: “NN” and “CUTS”.
ch/~bdl/lepc/lepc.ppt21 SM Higgs 1998 situation 1 excess of events (bbqq channel mostly) very good candidates at m h ~ 96 GeV m h >92.9 GeV (exp GeV) 1-Cb(96 GeV)~1% => is there a Higgs at 96 GeV?
ch/~bdl/lepc/lepc.ppt SM Higgs observed vs expected evts data MC data MC CUTS analysis
ch/~bdl/lepc/lepc.ppt23 SM Higgs 1999: se non e vero... ???Mass plots show interesting feature around 105 GeV??? BUT…mass plots can be very misleading! They add events with 1. different centre-of mass energies 2. Different b-tagging quality 3. Channel-dependent mass resolution (always >3 GeV!) Cb, C(s+b) and Likelihood ratio take these into account!
ch/~bdl/lepc/lepc.ppt24 What would be the shape of a 105 GeV signal?
ch/~bdl/lepc/lepc.ppt25 SM Higgs 1999: mass plots per energy GeV GeV GeV GeV
ch/~bdl/lepc/lepc.ppt26 SM Higgs 1999 ALEPH online PRELIMINARY 1.15 m h > GeV (exp ) ALEPH online PRELIMINARY No Higgs is always more likely than SM Higgs. Likelihood ratio: Cb max=0.87
ch/~bdl/lepc/lepc.ppt27
ch/~bdl/lepc/lepc.ppt28 SM Higgs cross-section measurement A GeV SM higgs with =0.25 SM) improves “ 2” by 1.3..
ch/~bdl/lepc/lepc.ppt29 MSSM Higgs boson m h > 89.9 GeV (exp: 88.3) tan excluded from 0.7 to 2.2 (! range will decrease with new theoretical calc.!)
ch/~bdl/lepc/lepc.ppt30 Charged Higgs H + H - ->cscs - -- Updated: cscs and cs from 189 GeV m H >71.0 GeV (exp. 72.2)
ch/~bdl/lepc/lepc.ppt31 Searches for Supersymmetry Same analyses as 1998 large m Bkg dominated by WW and qq small m Bkg dominated by “two-photon” and We NO background subtraction in general (except 4J, photons and acoplanar leptons)
ch/~bdl/lepc/lepc.ppt32 Slepton-Results Acoplanar leptons + missing mass
ch/~bdl/lepc/lepc.ppt33 Stop - Results (observe 10, expect 8.1)(observe 4, expect 2.8) Limits improve by 3-6 GeV c/w 189
ch/~bdl/lepc/lepc.ppt34 Sbottom - Results (observe 3, expect 2.7) 189 GeV only GeV
ch/~bdl/lepc/lepc.ppt35 Charginos + Neutralinos Results Neutralinos Charginos Background dominated by “two photon” and Wev, under investigation.
ch/~bdl/lepc/lepc.ppt36 Chargino Mass Limit (at large m 0 ) At large m 0 (heavy sleptons) cross-section is highest =>mass limit at kinematic limit 189 GeV + limit Limit increased by 6.5 GeV
ch/~bdl/lepc/lepc.ppt37 neutralino mass limit (at large m 0 ) ( was 32.3 GeV at 189 GeV) At large M 0 (heavy sfermions) only chargino and neutralino analyses needed to derive limit* Charginos+neutralinos M LSP > 36.5 GeV Charginos alone M LSP > 34.5 GeV * no higgs limit applied yet.
ch/~bdl/lepc/lepc.ppt38 LLE exclusion limits
ch/~bdl/lepc/lepc.ppt39 LQD exclusion limits
ch/~bdl/lepc/lepc.ppt40 RPV - UDD results * sliding mass cut
ch/~bdl/lepc/lepc.ppt41 UDD Sneutrino Excess? q q q q q q Selection: 4 jets+ E miss reconstruct the neutralino mass: force to 4 jets and choose pair of dijets with minimum mass difference UDD Sneutrino went away! ~~ 196 GeV 200 GeV! 202 GeV Sum of dijet masses
0.04 ~ ( j = 2 or 3 ) ee ee ee ee Charged Current Universality Constraints Exclusion ALEPH PRELIMINARY RPV: new search mode for LLE sneutrino Access to 7 out 9 couplings Access to M up to E cm 3 or 4 leptons with missing energy sneutrino e mass.
ch/~bdl/lepc/lepc.ppt43 Three search topologies depending on stau mass GMSB: NLSP Stable heavy leptons (0 obs/ 0.6 exp) Kinks,large impact parameter (1 obs/0.6 exp) MSSM Acoplanar leptons Lifetime independent mass limit M > 72 GeV Was 67 GeV
ch/~bdl/lepc/lepc.ppt44 Single Photon events e + e - -> G Gravity in extra dimensions N extra dimensions of size R D N mass scale M D R D 2 >1110 GeV <0.4 mm 3 >860 GeV <5 nm 584 obs, 591 exp Photons and anomalous W couplings Fit to single photon+Emiss selection =0.2±0.4±0.2 assuming =0 =0.4±0.7± only =0.3±0.7±0.2 assuming =0 =0.3±0.9± only W W e e
ch/~bdl/lepc/lepc.ppt45 Two Photons events e + e - -> G -> (no Emiss) 1599 observed, 1632 expected T (+)>987 GeV (189:>890 GeV) T (-)>866 GeV (189:>770 GeV)
ch/~bdl/lepc/lepc.ppt46 GMSB: Neutralino NLSP CDF event: qq->e + e - ->e + e - ->e + G e - G e + e - -> -> G G 34 observed, 35 expected >35 GeV: 3 obs, 2 exp 189 GeV limit ~~ ~ ~~ ~
ch/~bdl/lepc/lepc.ppt47 Conclusions 1. We will need to open TPC during the rather brief winter shut-down 2. Beautiful data at LEPII! 480 pb -1 on tape. We had a very nice summer and fall taking data at six different energies from the --very useful-- Z calibration data up to 204 GeV thanks to the two weeks extension. Congratulations to LEP, rf & operations ! Strong support for the mini-ramp scheme 3. ALEPH operations, software and analysis efficient and enthusiastic. 4. We have not found anything significant limits extend precision becomes very interesting -- and difficult at times. We are looking forward to next year’s data.