1. Searches for New Phenomena at CDF
Beate Heinemann, University of Liverpool
Introduction
Supersymmetry:
Higgs
Squarks and Gluinos
Charginos and Neutralinos
Indirect search: Bsmm
Non-SUSY:
Dilepton Mass Spectrum
Signatrure: Diphoton+X
Summary and Outlook
UCLA, March 15th 2006

2. The Standard Model H Matter is made out of fermions:
quarks and leptons
3 generations
Forces are carried by Bosons:
Electroweak: ,W,Z
Strong: gluons
Higgs boson:
Gives mass to particles
Not found yet H
UCLA, 03/15/06
B. Heinemann

3. What is Beyond the SM?
Many good reasons to believe there is as yet unknown physics beyond the SM
Many possible new particles/theories:
Supersymmetry:
Many flavours
Extra dimensions (G)
New gauge groups (Z’, W’,…)
New fermions (e*, t’, b’, …)
Leptoquarks
Can show up!
As subtle deviations in precision measurements
In direct searches for new particles
UCLA, 03/15/06
B. Heinemann

4. Supersymmetry can solve three
There is a Lot Unknown
The Standard Model
only accounts for 4% of matter in Universe
No candidate for Cold Dark Matter (≈25%)
cannot explain large mass hierarchy in fermion sector:
>10 orders of magnitude
does not allow grand unification:
electroweak and strong interactions do not unify
has large radiative corrections in Higgs sector
require fine-tuning of parameters
Cannot explain matter-antimatter asymmetry?
Supersymmetry can solve three
of these problems
Hubble Constant
Matter Density SM
UCLA, 03/15/06
B. Heinemann

5. What’s Nice about Susy? Unifications of forces possible With SUSY
Dark matter candidate exists:
The lightest neutral gaugino
Radiative corrections to Higgs acquire SUSY corrections:
No fine-tuning required
Changes relationship between mW, mtop and mH:
Also consistent with precision measurements of MW and mtop
With SUSY
UCLA, 03/15/06
B. Heinemann

6. CDF and the Tevatron
UCLA, 03/15/06
B. Heinemann

7. Tevatron Run II _ p p World’s highest energy collider
Tevatron Accelerator:
Integrated luminosity >1.5 fb-1 by now:
CDF data taking efficiency about 83%
Integrate Ldt=4-8 fb-1 by 2009 _ p p
√s(TeV)
Dt(ns)
L(cm-2 s-1)
Run II
1.96
396
1.7x1032
Key parameter: N= • Ldt
Delivered: 1.6 fb-1
Recorded: 1.3 fb-1
UCLA, 03/15/06
B. Heinemann

8. Tevatron Luminosity
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B. Heinemann

9. Measurement of Final State Objects with CDF
SOLENOID
h = 2.0
END WALL HAD CAL.
CENTRAL OUTER TRACKER
CLC
CENTRAL HAD CALORIMETER
PLUG HAD CAL.
h = 1.0
h = 3.0
PLUG EM CAL.
MUON CHAMBERS
Silicon Vertex Detector
CENTRAL EM CALORIMETER
UCLA, 03/15/06
B. Heinemann

10. Measurement of Final State Objects with CDF
Electron ID :
Coverage : |h|<3.6
|h|<2 (w/ trk)
ID eff. ~ 80-90%
Photon ID :
Coverage : |h|<2.8
ID eff. ~ 80%
UCLA, 03/15/06
B. Heinemann

11. Measurement of Final State Objects with CDF
Muon ID :
Coverage : |h|<1
ID eff. ~ %
UCLA, 03/15/06
B. Heinemann

12. Measurement of Final State Objects with CDF
th ID
t cone
isolation
Tau ID :
Narrow iso. cluster
Low # tracks
p0 identification
Coverage : |h|<1
ID eff. ~ 46%
UCLA, 03/15/06
B. Heinemann

13. Measurement of Final State Objects with CDFx y z
Lxy b do
Jet ID :
Cluster of CAL towers
Coverage : |h|<3.6
Heavy Flavor Jet Tagging :
Id HF jets via semi-leptonic decay
Find soft lepton in jets
Coverage : |h|<1
Id HF jets via finding displaced vertex
Coverage : |h|<1.5
UCLA, 03/15/06
B. Heinemann

14. Supersymmetry
UCLA, 03/15/06
B. Heinemann

15. Supersymmetry g ~ G SM particles have supersymmetric partners:
Differ by 1/2 unit in spin
Sfermions (squarks, selectron, smuon, ...): spin 0
gauginos (chargino, neutralino, gluino,…): spin 1/2
No SUSY particles found as yet:
SUSY must be broken: breaking mechanism determines phenomenology
More than 100 parameters even in “minimal” models!
UCLA, 03/15/06
B. Heinemann

16. Sparticle Cross Sections: Tevatron
Cross Section (pb)
150 events
produced so
far (1.5 fb-1)
T. Plehn, PROSPINO
UCLA, 03/15/06
B. Heinemann

17. Sparticle Cross Sections: LHC
Cross Section (pb)
100 events
with 1 fb-1
T. Plehn, PROSPINO
UCLA, 03/15/06
B. Heinemann

18. Sparticle Cross Sections: LHC
100 events
with 1 pb-1
Cross Section (pb)
100 events
with 1 fb-1
T. Plehn, PROSPINO
UCLA, 03/15/06
B. Heinemann

19. Higgs in the MSSM Minimal Supersymmetric Standard Model:
2 Higgs-Fields: Parameter tanb=<Hu>/<Hd>
5 Higgs bosons: h, H, A, H±
Neutral Higgs Boson:
Pseudoscalar A
Scalar H, h
Lightest Higgs (h) very similar to SM
At high tanß:
A is degenerate in mass with either h or H
Decay into either tt or bb for mA<300 GeV:
BR(A tt) ≈ 10%, BR(A bb) ≈ 90%
Cross section enhanced with tan2
C. Balazs, J.L.Diaz-Cruz, H.J.He, T.Tait and C.P. Yuan, PRD 59, (1999)
M.Carena, S.Mrenna and C.Wagner, PRD 60, (1999)
M.Carena, S.Mrenna and C.Wagner, PRD 62, (2000)
UCLA, 03/15/06
B. Heinemann

20. Neutral MSSM Higgs Production mechanisms: Experimentally: bb  A/h/H
gg  A/h/H
Experimentally:
pp  b+X  bbb+X
pp  +X  tt +X
UCLA, 03/15/06
B. Heinemann

21. MSSM Higgs: Tau-Selection
Select t t Events:
One t decays to e or m
One t decays to hadrons
Require:
e or m with pT>10 GeV
Hadronic t:
Narrow Jet with low multiplicity
1 or 3 tracks in 10o cone
No tracks between 10o and 30o:
Cone size descreasing with increasing energy
Low p0 multiplicity
Mass<1.8 GeV
Kinematic cuts against background:
W+jets
Photon+jets
Dijets
UCLA, 03/15/06
B. Heinemann

22. Acceptance and Background
Main background:
Drell-Yan tt
Indistinguishable signature => Separate kinematically
No full mass reconstruction possible for low Higgs pT:
Form mass like quantity: mvis=m(t,e/m,ET)
Good separation between signal and background
Data mass distribution agrees with SM expectation:
mvis>120 GeV:
8.4±0.9 expected, 11 observed
UCLA, 03/15/06
B. Heinemann

23. MSSM Higgs: Results CDF pp  A+X tt+X Brandnew result from DØ
Sensitivity at high tanb
Exploting regime beyond LEP
Brandnew result from DØ
Combined with other mode
pp  bA+Xbbb+X
Future (L=8 fb-1):
Probe values down to 25-30!
UCLA, 03/15/06
B. Heinemann

24. 3rd generation Squarks ~ ~ 3rd generation is special:
Masses of one can be very low due to large SM mass
Particularly at high tan
Direct production or from gluino decays:
pp bb or tt
pp gg bbbb or tttt
Decay of sbottom and stop:
b b0
Stop depends on mass:
Heavy: t t0
Medium: t b± bW0
Light: t c0 ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
UCLA, 03/15/06
B. Heinemann

25. Bottom Squarks This analysis: Spectacular signature: ~ ~
Gluino rather light: GeV
BR(g->bb)=100% assumed
Spectacular signature:
4 b-quarks + ET
Require b-jets and ET>80 GeV ~ ~
Expect:2.6±0.7
Observe: 4
Exclude new parameter space in gluino vs. sbottom mass plane
UCLA, 03/15/06
B. Heinemann

26. Light Stop-Quark: Motivation
If stop quark is light:
decay only via t->cc10
E.g. consistent with relic density from WMAP data
Balazs, Carena, Wagner: hep-ph/
WCDM=
m(t)-m(c10)≈15-30 GeV/c2
m(t)<165 GeV/c2
Search for 2 charm-jets and large Et:
ET(jet)>35, 25 GeV
ET>55 GeV ~ ~ ~ ~ ~
UCLA, 03/15/06
B. Heinemann

27. Light Stop-Quark: Result
Charm jets:
Use “jet probability” to tag charm:
Probability of tracks originating from primary vertex
Improves signal to background ratio:
Signal Efficiency: 30%
Background rejection: 92%
Data consistent with background estimate
Observed: 11
Expected:
Main background:
Z+ jj -> vvjj
W+jj -> tvjj
UCLA, 03/15/06
B. Heinemann

28. Stop Quark: Result and Future
Due to slight excess in data:
No limit set on stop quark mass yet
Future light stop reach :
L=1 fb-1: m(t)<160 GeV/c2
L=4 fb-1: m(t)<180 GeV/c2
LHC:
Direct production will be tough to trigger
But gluino decay to stop and top yields striking signature!
Two W’s, two b-quarks, two c-quarks and missing ET
If m(g)>m(t)+m(t) ~ ~ ~ ~
UCLA, 03/15/06
B. Heinemann ~ ~ ~ ~ ~ ~ ~ ~

29. Charginos and Neutralinos
Charginos and Neutralionos:
SUSY partners of W, Z, photon, Higgs
Mixed states of those
Signature:
3 leptons +
Recent analyses of EWK precision data:
J. Ellis, S. Heinemeyer, K. Olive, G. Weiglein:
hep-ph/
Light SUSY preferred ~ Et
UCLA, 03/15/06
B. Heinemann Et Et

30. 3 leptons + Et Many analyses to cover full phase space:
Low tan:
2e+e/m
2m+e/m
me+e/m
High tan:
2e+isolated track
Sensitive to one-prong tau-decay
Other requirements:
Dilepton mass >15 GeV and not within Z mass range
Less than 2 jets
Significant ET
UCLA, 03/15/06
B. Heinemann

31. Trileptons: Result Still no SUSY! Will need to set limit Analysis
Expected
background
Example SUSY
Data
Trilepton (+l)
0.640.18
1.60.2 1
Trilepton (e+l)
0.780.13
1.00.2
Trilepton (ee+l)
0.170.05
0.50.1
Dielectron+track
0.490.14
1.20.1
Trilepton(+l)
0.130.03
Still no SUSY!
Will need to set
limit
UCLA, 03/15/06
B. Heinemann

32. 3-muon Event
CMIO
MET
CMUP
CMX
UCLA, 03/15/06
B. Heinemann

33. Rare Decay: Bsm+m- SM rate heavily suppressed:
SUSY rate may be enhanced:
Related to Dark Matter cross section (in one of 3 cosmologically interesting regions)
Recently gained a lot of attention in WMAP data SUSY analyses, see e.g.
B. Allanach, C. Lester: hep/ph
J. Ellis et al., hep-ph/
S. Baek, Y.G.Kim, P. Ko, hep-ph/
R. Dermisek et al., hep-ph/
(Buchalla & Buras, Misiak & Urban)
(Babu, Kolda: hep-ph/ many more)
S. Baek, Y.G.Kim, P. Ko, hep-ph/
UCLA, 03/15/06
B. Heinemann

34. Bsm+m- vs. Trileptons 1x10-7 Trileptons: 2fb-1
A.Dedes, S. Mrenna, U. Nierste, P. Richardson hep-ph/
1x10-7
Trileptons: 2fb-1
UCLA, 03/15/06
B. Heinemann

35. Indirect Search: Bs->mm
Preselection:
Two muons with pT>1.5 GeV/c
Dimuon vertex displaced from primary
Identify variables that separate signal from background:
Decay length: 
Points towards primary vertex
Isolated from other tracks
Construct likelihood of variables:
Excellent separation
Cut at likelihood ratio >0.99
UCLA, 03/15/06
B. Heinemann

36. Bs->mm :Result and Future
0 events observed
Backgrounds:
0.81± 0.12 for (CMU-CMU)
0.66 ± 0.13 for (CMU-CMX)
Branching Ratio:
CDF:
BR(Bs->mm)<1.5 x 10-7 at 90%C.L.
Combined with D0:
BR(Bs->mm)<1.2 x 10-7 at 90%C.L.
Future:
Probe values of 2x10-8
UCLA, 03/15/06
B. Heinemann

37. Impact of Bsm+m- limits: Now
A.Dedes, S. Mrenna, U. Nierste, P. Richardson hep-ph/
S. Baek, Y.G.Kim, P. Ko, hep-ph/
Starting to constrain MSSM parameter space
UCLA, 03/15/06
B. Heinemann

38. Impact of Bsm+m- limits: L=8 fb-1
A.Dedes, S. Mrenna, U. Nierste, P. Richardson hep-ph/
S. Baek, Y.G.Kim, P. Ko, hep-ph/
Tevatron will severely constrain parameter space
UCLA, 03/15/06
B. Heinemann

39. Impact of Bsm+m- limits: LHC
A.Dedes, S. Mrenna, U. Nierste, P. Richardson hep-ph/
S. Baek, Y.G.Kim, P. Ko, hep-ph/
LHC will probe SM value with about 100 fb-1
UCLA, 03/15/06
B. Heinemann

40. Non-Susy Searches

41. High Mass Dileptons Standard Model high mass dilepton production:
New physics at high mass:
Resonance signature:
Spin-1: Z’, W’
Spin-2: Randall-Sundrum (RS) Graviton
Spin-0: Higgs, Sneutrino
Tail Enhancement:
Contact Interactions
Large Extra Dimension (Arkhani-Hamed, Dimopoulos, Dvali)
UCLA, 03/15/06
B. Heinemann

42. Z´ee Search Dielectron mass spectrum and angular distribution:
2D analysis improves sensitivity
Data agree well with Standard Model spectrum
No evidence for mass peak
UCLA, 03/15/06
B. Heinemann

43. Z´ee Signal Examples
Angular distribution has different sensitivity for different Z’ models
UCLA, 03/15/06
B. Heinemann

44. Limits on New Physics Mass peak search:
Tail enhancement: contact interaction
Model
ZSM Z Z Z ZI ZN
Zsec
Mass limit (GeV/c2)
860
735
725
745
650
710
675
UCLA, 03/15/06
B. Heinemann

45. Signature Based Searches
All searches cover unique signatures, e.g.:
Three lepton and missing ET
B- or c-jets and missing ET
2 b--jets or c-jets and missing ET
Dilepton invariant mass
However, can also search really model independent to make sure we don’t miss anything!
Diphoton+X
UCLA, 03/15/06
B. Heinemann

46. Signature: Diphoton+X
Search for any objects produced in association with 2 photons
Electron, muon, tau
Photon
Jet
Missing ET
Data consistent with background prediction
=e,m,g SM
Data
+e
4.50.8 2

0.50.1

1.90.6 4
ET
0.30.1
UCLA, 03/15/06
B. Heinemann

47. Diphoton+X: Invariant Mass
Kinematic distributions also agree well with background prediction
Triphoton analysis first physics result with >1 fb-1 of data!
UCLA, 03/15/06
B. Heinemann

48. Summary and Outlook CDF and Tevatron running great! more than 1 fb-1!
Most analyses based on up to pb-1
Will analyze 1 fb-1 by summer 2006
Anticipate fb-1 by 2009
Searches probe Nature in new, unique way
Tevatron most powerful tool today:
provide world’s best constraints on nearly anything that is being searched for
LHC will be very powerful in the future
It is an exciting time
more than 1 fb-1!
UCLA, 03/15/06
B. Heinemann

49. Backup Slides

50. Dirac Magnetic Monopole
Bends in the wrong plane ( high pt)
Large ionization in scint (>500 Mips!)
Large dE/dx in drift chamber
TOF trigger designed specifically for monopole search
mmonopole > 350 GeV/c2
UCLA, 03/15/06
B. Heinemann

51. GMSB: gg+Et ~ ~ ~ ~ D0+CDF: m(c+1)> 209 GeV/c2 Assume c01 is NLSP:
Decay to G+g
G light: m ≈ 1 keV
Inspired by CDF eegg+Et
event in Run I
SM exp.: 10-6
D0 (CDF) Inclusive search:
2 photons: Et > 20 (13) GeV
Et > 40 (45) GeV ~ ~ ~
Exp.
Obs.
m(c+1) D0
2.5±0.5 1
>192 GeV
CDF
0.3±0.1
>168 GeV
D0+CDF: m(c+1)> 209 GeV/c2
UCLA, 03/15/06
B. Heinemann

52. Tevatron: Future
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53. SUSY Particles
gravitino
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B. Heinemann

54. Neutral Spin-1 Bosons: Z’
2 high-PT electrons, muons, taus
Data agree with BG (Drell-Yan)
Interpret in Z’ models:
E6-models: y, h, c, I
SM-like couplings (toy model)
UCLA, 03/15/06
B. Heinemann

55. Future High Energy Colliders
LHC (2007-?)
ILC (>2020?) p e+ p e-
√s=14 TeV
√s=0.5-1 TeV
UCLA, 03/15/06
B. Heinemann

56. Randall-Sundrum Graviton
Analysis:
2 photon mass spectrum
Backgrounds:
direct diphoton production
Jets: 0
Data consistent with background
Relevant parameters:
Coupling: k/MPl
Mass of 1st KK-mode
UCLA, 03/15/06
B. Heinemann

57. Randall-Sundrum Graviton
Analysis:
2 photon mass spectrum
Backgrounds:
direct diphoton production
Jets: 0
Data consistent with background
UCLA, 03/15/06
B. Heinemann

58. Extra Dimensions
Attempt to solve hierarchy problem by introducing extra dimensions at TeV scale
ADD-model:
n ED’s large: 100mm-1fm
M2PL ~ Rn MSn+2 (n=2-7)
Kaluza-Klein-tower of Gravitons continuum
Interfere with SM diagrams: l=±1 (Hewett)
Randall Sundrum:
Gravity propagates in single curved ED
ED small 1/MPl=10-35 m
Large spacing between KK-excitations
 resolve resonances
Signatures at Tevatron:
Virtual exchange:
2 leptons, photons, W’s, Z’s, etc.
BR(G->gg)=2xBR(G->ll) KK
ee, mm, gg q _ q
UCLA, 03/15/06
B. Heinemann