Title: Searches Before LHC
1Searches Before LHC
a snapshot
Cristinel DIACONU Centre de Physique des
Particules de Marseille and Deutsches Elektronen
Synchrotron Hamburg
- Introduction
- Standard Model and Higgs
- Signature based searches
- Generic searches
- Low energy results
- Conclusions
June 1st, 2007, Four Seas Conference, Iasi,
Romania
1
2Colliders at Fermi Scale
before LHC (pp, 14 TeV)
e
p
TEVATRON
LEP
e
p
FERMILAB
HERA
1.96 TeV
209 GeV
DESY
320 GeV
Low energy contraints can also access these
scales precision can beat decoupling
3LEP/SLC
ALEPH, DELPHI, L3, OPAL
L900 pb-1/expt.
SLC (SLD) polarized ee- at Z peak
WW
4HERA
- HERA 1 1992-2000 120 pb-1/expt
- HERA 2 2003-2007 luminosity upgrade
ep
H1 Harvest at HERA 12 0.5fb-1
e-p
2000
Since April 2007 Low Energy Run Ep460 GeV
e-p
ep
1998
2003
ep
HERA program entering an exciting period final
analyses
4
5Tevatron
-gt pp collider CDF, D0 Run I Ecm1.8 TeV 130
pb-1/exp.(phys.) Run II Ecm1.96 TeV
Prospects
Analyses with 1fb-1 , a lot more to go still
6Standard Model Status
- Consistency check of the SM based on high
precision measurements - More than 1000 data points combined in 17
observables calculated in the SM from - aem (precision 3.10-9) the critical part ?ahad
(from ee--gthadrons) - GF (precision 9.10-6) (-gtMW )
- MZ (precision 2.10-5) from lineshape (LEP-1)
- as (MZ) (precision 2.10-2) hadronic observables
- Mtop and MHiggs
- Zfitter 6.42, precision at 2 loop (MW , sin2?W)
3-loop for ?
7Mtop and MW
CDF MW 80413 48 MeV
Tremendous progress in direct mesurements at
Tevatron Higgs particle may be round the corner
(or not)
Mhiggs7633-24 GeV
Mhiggslt144 (182) GeV
8Direct Higgs Searches at Tevatron
9Event with isolated e or m and PTmiss
Full HERA Luminosity
SM W Total Cross Section 1.3 pb gt 5
events/100pb-1with e or m
PTmiss
(70 signal)
Only electrons contribute 0ltPTXlt12 GeV
Hadronic system (X)
isolated electron
Evidence for W production at HERA Continue to
observe events at high PTX gtLook more
differentially in ep/e-p data samples
H1 HERA 1 (118 pb-1, mainly ep)
PTXgt25 GeV 11 (Data) / 3.50.6 (SM)
(3s)
9
10H1 Results (e and µ) ep vs. e-p data
ep
e-p
Different observations in ep and e-p. ZEUS do
not support this observation
3sigma
10
11Events with leptons and photons
12Di-leptons searches (Tevatron)
Two electrons with PTgt25 GeV
13Multilepton events at HERA
New Result Full HERA statistics
H1/HERA I observation of multi-electrons at
high mass Include muons combinations ee, em,
mm, eee, emm SPT hardness of the events
SM dominated by
For SPTgt100 GeV, ep data 4/1.20.2
13
14Search for lepton-boson resonances
full HERA Ecm320 GeV luminosity
Unambiguous signature for matter substructure
direct observation of excited states
Lepton-Boson Resonances eg, nW, eZ
14
15Excited electrons(Tevatron)
?M(e) M(e)lt800 GeV excluded _at_ 95 CL (CI
formalism)
16Multi-leptons at Tevatron
Trileptons very small background spectacular
signature Can come from SUSY cascades
CDF 14 topologies (e,µ, tracks)
D04 topologies
Inclusive techniques deployed Very low number of
events No significant deviation found
LSlikesign
17SUSY constraints from multi-leptons
MSUGRA
18Search for lepton-jet resonances
LQ
HERA II, e-p, 92 pb-1
Lepton-jet resonance
example scalar LQ
ejet
NC
PTmissjet
CC
More data, e/e-p, (x2) final domain to explore
18
19Leptoquarks at Tevatron
Complex particle identification LQ 2nd and 3rd
generations
LQ
LQ
20Single production at Tevatron
PLB 647, 74 (2007)
Here second generation LQ2
singlepairs ß1/2
LQ single
singlepairs ß1
More mechanisms, more sensitivity
single production gain for larger couplings
21Mass-coupling limits
LQ2
LQ3
Mgt317 GeV _at_ 95 CL
Mgt214 GeV _at_95 CL
22Multi-photon events at Tevatron
Motivated by the anomalous ee?? Etmiss event (run
I)
Good agreement with the Standard Model
23New result Full HERA II
- Search for isolated particles at high PT
- Electrons ,Photons, Muons, Hadronic Jets,
Neutrinos
- Unique phase space
- PT gt20 GeV
- 10olt?lt140o
D0, PRD64, 012004 (2001) H1, Phys Lett B602
(2004) 14
- Statistical Analysis (search for deviations)
m n jet
23
24Vista and Sleuth _at_ CDF
D0 also recently involved
Similar general search, but phase space adjusted
on background
Experimental effort is huge, but worth Security
belt for the unexpected
25Low Energy, high precision
Beat Decoupling?
Bs?µµ-
aµ(gµ-2)/2
(SM 3.4 10-10)
26A celebration positron is 75
Positron discovery Anderson 1932
Dirac equation 1928
Heisenberg (1960's) Up till that time, I had
the impression that, in quantum theory, we had
come to a harbour. This discovery threw us into
the sea again.
LHC -gt Four Seas?
from F.Wilczek's Fantastic realities
27Conclusions and outlook
- Standard Model in best shape ever
- Present fronteer colliders continue to explore
new teritory before LHC - In the last 2 year the luminosity at HERA and
Tevatron x2 - HERA data in the can, scrutinise, discover,
report - Tevatron still large factors (5-8) to go, high
hopes - The start of the LHC will be an interesting
period, - a surprise can occur however before
LHC