ALEPH in 1999 Alain Blondel Ecole Polytechnique z

ALEPH in 1999 Alain Blondel, Ecole Polytechnique z Data quality at 192 -196 -200 -202 Ge. V z LEPI reprocessing finished! z Standard processes are still there: y 2 -fermion and , QCD, WW z anything new? y. Higgs y. Supersymmetry http: //alephwww. cern. ch/~bdl/lepc. ppt 1

Z-192 -196 -200 -202 Ge. V ALEPH data z ALEPH efficiency: 95. 6% z 93. 3% of delivered pb-1 used for analysis http: //alephwww. cern. ch/~bdl/lepc. ppt 2

Tracking �eam loss on 27 July => large TPC distortion -- seen on-line B � Z run beg. August => understand correct Impact parameter (sum d 0) of Bhabhas at LEPII microns Short in TPC field cage, causes distortions, can be corrected using Z data + Maxwell&Langevin eqns. 0 -100 http: //alephwww. cern. ch/~bdl/lepc. ppt Run number--> 3

Tracking �rift in impact params continues, D need to be fixed using Z run in october. will �equires reprocessing, not available for the data presented today R => slightly worse tracking and b-tagging for 200 -202 Ge. V data � WILL REQUIRE OPENING TPC during winter shut-down! � http: //alephwww. cern. ch/~bdl/lepc. ppt 4

B-tagging ALEPH preliminary b jets udsc jets ALEPH preliminary b jets VDET 100% operational all year!. Additional smearing necessary to get good agreement data/MC. udsc bkg in 4 b evts underestimated: 5(192 -196)-10%(200 -202). will be improved by reprocessing e. g. : h. A(bbbb) preselection: h. A http: //alephwww. cern. ch/~bdl/lepc. ppt udsc jets qq zz ww 5

Reprocessing of LEPI data and MC now finished Many analyses going on. preliminary results produced so far with reprocessed data: -DGs (Vancouver 98) - B 0/B+ lifetimes (Moriond 99) - AFB(b) AFB(c) (Tampere 99) - Leptonic decays of the Ds (Tampere 99) - Inclusive searches for CP violation (Tampere 99) - Today’s special: CP asymmetry in B -> J/Y Ks http: //alephwww. cern. ch/~bdl/lepc. ppt 6

CP asymmetry in B -> J/Y Ks Select J/Y->ee, mm Ks -> p+p- 23 events/6. 4 bkg ALEPH 99 -099 conf 99 -054 Measure lifetime, tag charge at production: jet charges, kaon, vertex and lepton charge - P(B)= 1 - P(B) at production B 8 events 15 events B Proper time ACP (t )=-sin(2 b) sin (Dmb t) http: //alephwww. cern. ch/~bdl/lepc. ppt sin(2 b) = 0. 93 +0. 64 + 0. 36 -0. 88 - 0. 24 7

B -> J/Y Ks event http: //alephwww. cern. ch/~bdl/lepc. ppt ALEPH 99 -099 conf 99 -054 8

CP asymmetry in B ->J/Y Ks ALEPH 99 -099 conf 99 -054 Compare/combine with CDF and OPAL: sin(2 b) = 0. 91 +- 0. 35 sin(2 b)>0 at 98. 5%CL (CDF alone 93%CL) http: //alephwww. cern. ch/~bdl/lepc. ppt 9

FIRST LOOK AT 1999 data: General features z VERY preliminary results z reprocessing and MUCH MORE UNDERSTANDING needed before data can be presented at conferences ! z analysis of ~229 pb-1 (Higgs: 237 pb -1 i. e. everything -> Yesterday!(8/11/99)) z All limits are at 95% CL z Analyses procedures and cuts defined BEFORE DATA TAKING http: //alephwww. cern. ch/~bdl/lepc. ppt 10

Multihadronic events http: //alephwww. cern. ch/~bdl/lepc. ppt as(m. Z)=0. 1209+-0. 0041 from LEPII data 11

Multihadronics http: //alephwww. cern. ch/~bdl/lepc. ppt <Nch>=27. 47+-0. 44+-0. 37 at 202 Ge. V 12

multihadrons http: //alephwww. cern. ch/~bdl/lepc. ppt 13

2 -fermion processes Precision becomes interesting! http: //alephwww. cern. ch/~bdl/lepc. ppt Th. Error on Bhabha x-section 2% 14

2 -fermion processes http: //alephwww. cern. ch/~bdl/lepc. ppt 15

FCNC Single top production 1998 Results Observed 18 (16 bcqq; 2 bcln) Expected 11. 5 (10. 5 bcqq; 1 bcln) P(exp = 11. 5; obs ³ 18) = 4. 6% Small excess (Not seen by DELPHI) 1999 Results: 192 5 Cand 2. 1 exp 196 10 Cand 11. 0 exp 200 10 Cand 10. 0 exp 202 5 Cand 3. 2 exp Tot 30 Cand http: //alephwww. cern. 26. 3 exp ch/~bdl/lepc. ppt Last year excess not confirmed ! 16

WW and ZZ production W branching ratios with all LEPII data: cross-sections low (- 4. 5 +- 1. 4)% wrt theory. Jadach et al hep-ph/9907436, Dittmaier et al hep-ph/9909363: non-universal corrections => ~ - (1 -2)% http: //alephwww. cern. ch/~bdl/lepc. ppt Br (W->en) = (11. 29+-0. 33+-0. 25)% Br (W->mn) = (10. 95+-0. 31+-0. 25)% Br (W->tn) = (10. 70+-0. 39+-0. 25)% Br (W->qq’) = (67. 06+-0. 47+-0. 50)% SM: 10. 83%; 67. 5% 17

Mass resolution WW->qqqq ZZ->llqq WW->lvqq WW->tvqq http: //alephwww. cern. ch/~bdl/lepc. ppt 18

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 So, I the evidence? > Su un ar j et ev have h gome > voc eard ents nto c e che a a t A o Sincerely, leph Higgs r mple > Ho corre ta p umo with A r -- s > di kins) che negli USA mente div $ r b e ( $ W y ' s event ALEP e o o , ( r a u uld b one b ix or se so, c' ll'Un w i Hig H i > di l e' una ling ven f e con ivers avreb ackg gs be fondo t i o our t r s b h a o i t e n ' c s u i John o t gia' u piu' a > irridu n e m w d n t m e s with xpec n cer ent? lto de cibile 4 j, 6 ( a ted. t o l > E' b c " n d o n h umer r e u u e ci s t m a t vero? a e 1 e r d 05 G o di e o i i aspe > ou h. Regar e. V). ventsi cand y tta. e d v s g a g > Gr 1. H "Hi azie. f 7 o e Cord nd u hav ialme o y r e g nte, ack y th b a s d ate leph s m u i A t b on ts at ess ject: u e r g e , n ALE ds h s) eve V data H Date: n e PH h i e r e i f c , i G F t r > r r u 0 i e , 1 O as disc o o ced v he 20 G S r ct 19 over e eting > la 4 in t p 9 s i f rom 12: 0 ed Higg from > d =~10 SLA 4: 03 s at 1 DES h ? C C g m + 05 G h Y n , 0 e >. Ru. . . ) is ers, 200 thi y m ( n MET e. V: ple that o u r >a ase c you here DST Subject: press release? h omm ( ) a s v o > e fou meb ent o Date: Tue, 2 Nov 1999 11: 22: 45 -0500 (Eastern Standard Time) nd t he H dy from iggs. An FNAL, w y co So when is CERN having a press release announcing the Higgs boson discovery? mme ho had hear nts? What's the mass? Rumors abound over here, and everyone is sure the silence d it means it's true. Best, G HIGGS BOSON SEARCH http: //alephwww. cern. ch/~bdl/lepc. ppt 19

Neutral Higgs boson search e+e- -> h. Z; h. A -Analysis is straight extrapolation of 189 Ge. V 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: h. Z-> bbqq h. Z-> bbnn h. Z-> bbll h. Z, h. A->bbbb, bbtt, ttqq, (tttt) treatment of overlaps by and/exclusives. Two streams of analyses: “NN” and “CUTS”. http: //alephwww. cern. ch/~bdl/lepc. ppt 20

SM Higgs 1998 situation 1 s excess of events (bbqq channel mostly) very good candidates at mh~96 Ge. V mh >92. 9 Ge. V (exp. 95. 9 Ge. V) 1 -Cb(96 Ge. V)~1% => is there a Higgs at 96 Ge. V? http: //alephwww. cern. ch/~bdl/lepc. ppt 21

1998 -1999 SM Higgs observed vs expected evts CUTS analysis data MC data http: //alephwww. cern. ch/~bdl/lepc. ppt MC 22

SM Higgs 1999: se non e vero. . . ? ? ? Mass plots show interesting feature around 105 Ge. V? ? ? 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 Ge. V!) Cb, C(s+b) and Likelihood ratio take these into account! http: //alephwww. cern. ch/~bdl/lepc. ppt 23

What would be the shape of a 105 Ge. V signal? http: //alephwww. cern. ch/~bdl/lepc. ppt 24

SM Higgs 1999: mass plots per energy 191. 6 Ge. V 195. 5 Ge. V 199. 5 Ge. V 201. 6 Ge. V http: //alephwww. cern. ch/~bdl/lepc. ppt 25

SM Higgs 1999 Cb max=0. 87 -> Likelihood ratio: No Higgs is always more likely than SM Higgs. ALEPH online PRELIMINARY 1. 15 s-> ALEPH online PRELIMINARY http: //alephwww. cern. ch/~bdl/lepc. ppt mh> 105. 6 Ge. V (exp. 106. 5) 26

http: //alephwww. cern. ch/~bdl/lepc. ppt 27

SM Higgs cross-section measurement A 103. 5 Ge. V SM higgs with s=0. 25 s(SM) improves “ 2” by 1. 3. . http: //alephwww. cern. ch/~bdl/lepc. ppt 28

MSSM Higgs boson mh > 89. 9 Ge. V (exp: 88. 3) tan b excluded from 0. 7 to 2. 2 (! range will decrease with new theoretical calc. !) http: //alephwww. cern. ch/~bdl/lepc. ppt 29

Charged Higgs - -H+H-->cscs Updated: cscs and cstn; tntn from 189 Ge. V m. H >71. 0 Ge. V (exp. 72. 2) http: //alephwww. cern. ch/~bdl/lepc. ppt 30

Searches for Supersymmetry Same analyses as 1998 large Dm Bkg dominated by WW and qq small Dm Bkg dominated by “two-photon” and Wen => NO background subtraction in general (except 4 J, photons and acoplanar leptons) http: //alephwww. cern. ch/~bdl/lepc. ppt 31

Slepton-Results Acoplanar leptons + missing mass http: //alephwww. cern. ch/~bdl/lepc. ppt 32

Stop - Results (observe 10, expect 8. 1) (observe 4, expect 2. 8) Limits improve by 3 -6 Ge. V c/w 189 http: //alephwww. cern. ch/~bdl/lepc. ppt 33

Sbottom - Results (observe 3, expect 2. 7) 189 Ge. V only http: //alephwww. cern. ch/~bdl/lepc. ppt 189 -202 Ge. V 34

Charginos + Neutralinos Results Charginos Neutralinos Background dominated by “two photon” and Wev, under investigation. http: //alephwww. cern. ch/~bdl/lepc. ppt 35

Chargino Mass Limit (at large m 0) At large m 0 (heavy sleptons) cross-section is highest =>mass limit at kinematic limit 189 Ge. V + limit Limit increased by 6. 5 Ge. V http: //alephwww. cern. ch/~bdl/lepc. ppt 36

neutralino mass limit (at large m 0) At large M 0 (heavy sfermions) only chargino and neutralino analyses needed to derive limit* Charginos alone MLSP> 34. 5 Ge. V Charginos+neutralinos MLSP> 36. 5 Ge. V ( was 32. 3 Ge. V at 189 Ge. V) * no higgs limit applied yet. http: //alephwww. cern. ch/~bdl/lepc. ppt 37

LLE exclusion limits http: //alephwww. cern. ch/~bdl/lepc. ppt 38

LQD exclusion limits http: //alephwww. cern. ch/~bdl/lepc. ppt 39

RPV - UDD results * sliding mass cut http: //alephwww. cern. ch/~bdl/lepc. ppt 40

UDD Sneutrino Excess? 196 Ge. V q q ~ ~ q q 200 Ge. V! Selection: 4 jets+ Emiss reconstruct the neutralino mass: force to 4 jets and choose pair of dijets with minimum mass difference 202 Ge. V UDD Sneutrino went away! http: //alephwww. cern. ch/~bdl/lepc. ppt Sum of dijet masses 41

RPV: new search mode for LLE sneutrino e± em g ALEPH PRELIMINARY e± mm em ( j = 2 or 3 ) m± 0. 04 Charged Current Universality Constraints Exclusion Access to 7 out 9 l couplings Access to M up to Ecm 3 or 4 leptons with missing energy sneutrino e m mass. ~

GMSB: NLSP Three search topologies depending on stau mass MSSM Acoplanar leptons Stable heavy leptons (0 obs/ 0. 6 exp) Lifetime independent mass limit M > 72 Ge. V Was 67 Ge. V http: //alephwww. cern. ch/~bdl/lepc. ppt Kinks, large impact parameter (1 obs/0. 6 exp) 43

Single Photon events Gravity in extra dimensions N extra dimensions of size RD e+e- -> G N 2 3 584 obs, 591 exp mass scale MD >1110 Ge. V >860 Ge. V Photons and anomalous W couplings RD <0. 4 mm <5 nm e e n W W n Fit to single photon+Emiss selection Dk =0. 2± 0. 4± 0. 2 assuming l =0 Dk =0. 4± 0. 7± 0. 2 189 only l =0. 3± 0. 7± 0. 2 assuming Dk =0 http: //alephwww. cern. ch/~bdl/lepc. ppt l =0. 3± 0. 9± 0. 2 189 only 44

Two Photons events e+e- -> G -> (no Emiss) 1599 observed, 1632 expected LT(+)>987 Ge. V (189: >890 Ge. V) LT(-)>866 Ge. V (189: >770 Ge. V) http: //alephwww. cern. ch/~bdl/lepc. ppt 45

GMSB: Neutralino NLSP e+ e- ~ ~ -> G G 34 observed, 35 expected >35 Ge. V: 3 obs, 2 exp http: //alephwww. cern. ch/~bdl/lepc. ppt CDF event: ~ ~ ~+~ + + qq->e e ->e e ->e G 189 Ge. V limit 46

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 Ge. V 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. http: //alephwww. cern. ch/~bdl/lepc. ppt 47