1. There’s Something About SUSY
m. spiropulu
EFI/UofC
oct

2. about SUSY Something Heavy
Supersymmetry is the most plausible solution of the hierarchy (issue) 
Something Light
low energy Supersymmetry is required 
Something Dark
might provide the missing matter of the universe
if the lightest neutralino is stable
Something Beautiful
the symmetry between fermions and bosons
Something Cool
they couple with known and sizable strengths
Something Exotic
a component of string theory
Something Urgent
testable at high enough energies (now)

3. SUSY is not a (super)model
SUSY is a spontaneously broken spacetime symmetry

4. bosons-fermions I Bosons: Commuting fields Integer spin particles
Bose statistics
Fermions:
Anticommuting fields
Half-integer spin particles
Fermi statistics
[anticommutativity ab=-ba and aa=-aa=a2=0 If a is the operator that creates an electron into a given state, a2 creates two electrons into the same state.]
A superspace has extra anticommuting coordinates q
anticommutativity ab=-ba and aa=-aa=a2=0 If a is the operator that creates an electron into a given state, a2 creates two electrons into the same state. C’est pa possible: This operator vanishes and the probability to have two electrons in the same state also vanishes. There is no (nonzero) state with two fermions in the same state (Pauli).

5. bosons-fermions II
If we Taylor expand an electron (anticommuting field) in the extra coordinates
electron field in superspace = selectron(boson) + electron(fermion)
For each boson of spin J there is a fermion of spin J±½ of equal mass
 This picture is not telling the whole story:SUSY is broken
 The masses of the superparticles are not equal with their corresponding
particles (or we would have seen them already).
 So we start SUSY with a few new parameters and introduce a bunch
more of what are called “soft breaking terms”: the masses of all the
superparticles.
Photon
W,Z
gluon
Squark
slepton
Photino
Wino,Zino
gluino
quark
lepton
quark
quark
gluino
gluon
squark
quark
equal couplings

6. general MSSM:370 parameters

7. particle content M1 M2 M3

8. supersymmetry in colliders
 Tevatron mass reach: 400 – 600 GeV for gluinos,
150 – 250 GeV for charginos and
neutralinos
200 – 300 GeV for stops and sbottoms
 LHC reach: 1 – 3 TeV for almost all sparticles
If SUSY has anything to do with generating the
electroweak scale, we will discover sparticles soon.
( no experimental direct evidence for SUSY today)

9. strong, weak, electromagnetic forces have comparable strengths
hierarchy of scales
10-17 cm
Electroweak scale
range of weak force
mass is generated (W,Z)
strong, weak, electromagnetic
forces have comparable strengths
10-33 cm
Planck scale
GN ~lPl2 =1/(MPl)2
1028 cm
Hubble scale
size of universe lu
16 orders of magnitude
puzzle
What kind of physics generates and stabilizes the 16 orders of magnitude difference between these two scales
1027 eV eV eV

10. bosons-fermions III Bose-Fermi Cancellation
SUSY SM
and the solution to the higgs naturalness problem
(the radiative corrections to the higgs mass can not
be 32 orders of magnitude larger than the higgs mass)

11. unification of couplings
The gauge couplings of the Standard Model converge to an almost common value at very high energy.
what’s up
with that?

12. unification of couplings
SUSY changes the slopes of the coupling constants
For MSUSY=1 TeV, unification appears at 3x1016 GeV

13. Proton’s (don’t) decay (fast)
In generic SUSies the proton could decay
We have measurements to the contrary effect
Satisfy this by conserving R-parity R=(-1)3(B-L)+2S

14. With R-parity conservation
370107 (soft breaking) parameters
The end of the decay chain of all SUSY particles is the lightest supersymmetric particle (LSP)
The properties of the LSP, generally determine the signature of SUSY
LSP is stable – great dark matter candidate; In many SUSY models it also weakly interacting.

15. example of mSUGRA SUSY
tanb m A
squarks/sleptons
gauginos
higgses

16. example collider signatures

17. example backgrounds

18. more SUSY models
Gauge mediated SUSY (LSP is the gravitino) photon-lepton signatures. M1:M2:M3=1:2:7
Anomaly mediated SUSY (LSPs are the Winos) disappearing tracks. M1:M2:M3=3:1:-8
String inspired models

19. SUSY mass clues Mass (GeV/c2) 220 190 170 97 45
Upper bound
(stau coanihilation)
TeVII reach
Red : most natural mass* D0
220
CDF
TeVII reach
190 D0
TeVII reach
Mass (GeV/c2)
170
CDF
D0 GMSB
CDF
LEP2 97
LEP2
CDF
LEP2 D0
LEP2
LEP2 GMSB
LEP2
LEP2
LEP2 45
LEP2 DM
LEP2
LEP2
* Anderson/Castano

20. the dark side of SUSY
Cosmology needs sources of non-baryonic dark matter  SUSies provide weakly interacting massive particles to account for the universe’s missing mass
neutralinos
sneutrinos
gravitinos 
We are closing in fast on either discovery or exclusion!
There is a good complementarity between direct, indirect, and collider searches  

21. 0.1 < Wc < 0.3 0.025 < Wc < 1 Tevatron reach
already excluded
CDMS, CRESST,
GENIUS
Tevatron reach
LHC does the rest
GLAST
0.1 < Wc < 0.3
0.025 < Wc < 1
J. Feng, K. Matchev, F. Wilczek

22.  How do we detect neutralino DM at colliders?
look at missing energy (LSP) signatures:
QCD jets + missing energy
like-sign dileptons + missing energy
trileptons + missing energy
leptons + photons + missing energy
b quarks + missing energy
etc. 

23. CDF 300 GeV gluino candidate:
gluino pair strongly produced,
decays to quarks + neutralinos

24. detectors

25. machines Tevatron pp 14 TeV 1034 LHC (27 Km) ~2 x Tevatron (3.2 Km)
Main Injector
and Recycler
p source
Booster
LHC (27 Km)
~2 x Tevatron (3.2 Km)

26. gluino decay path example

27. example cross sections
L is the Luminosity
e is the acceptance
(trigger included)
B is the Background
s is the cross section
(unit is area: the effective
scattering size of a process)
Total p/antip cross section is 7x10-30 m2
Unit of Barns (b) = 10-28m2
s(ppX)=70 mb
Run I L ~ 1031 crossings/cm2/sec
N/sec ~ sL = 7x105/sec
>1 interactions per beam crossing!
Cross Section for top production: s(pptt+X)=70 mb
This is around 1/1010 of total
N/sec ~ sL = 7x10-5/sec
A couple were created/day but we only
saw a small %
~100 events in 3 ys in two experiments

28. recording the physics: triggering

29. recording the physics: triggering

30. recording the physics: triggering

31. Calorimeter energy
Central Tracker (Pt,f)
Muon stubs
Cal Energy-track match E/P, Silicon secondary vertex
Multi object triggers
Farm of PC’s running
fast versions of
Offline Code  more
sophisticated selections

32. Missing ET + multijets (CDF)q f
Missing Energy provides R-parity conserving SUSY signatures (R=(-1)3B+L+2S) and also appears in many other phenomenological paradigms
MET + 3 jets (squarks,gluinos)
MET + dileptons + jets (squarks gluinos)
MET + c-tagged jets (scalar top)
MET + b-tagged jets (scalar bottom,Higgs)
MET + monojet (gravitino, graviton)
MET + photons (gravitino)

33. Production/Decay Graphs

34. “Fake” MET QCD Use to define fiducial jets gap cosmic Main Ring
 DETECTOR NOISE  COSMICS
eliminated with a set of timing and good jet quality requirements
Main Ring
& QCD mismeasurements
Use to
define
fiducial
jets
QCD
gap

35. Standard Model Missing Energy +jets
 Z/W +jets
MC norm to
Z data
 QCD
MC norm to
jet data
 top, dibosons
MC norm using theory cross section

36. Analysis 0 >0 “blind analysis” approach
HT=ET(2)+ET(3)+MET
Number of High PT isolated tracks
>0
“blind analysis” approach
where you expect your signal
don’t look until you are ready

37. Optimization for SUSY

38. comparisons around the “box”Q C D
Z(inv)
W(m,e)
top
W(t)

39. “The BOX”
The Box: SM Expected 76±13
Found
in data 74

40. “The other BOXes”
A/D SUSY boxes:
SM Expected 33±7
Found
in data 31

41. “The other BOXes”
SUSY box C:
SM Expected 10.6±1
Found
in data 14

42. LIMITS

43. Candidate Event
Knowledge from this analysis applied in monojet+MET analysis
with RunI data that can search for associate gluino-neutralino
production (also KK graviton etc).

44. There’s Something About the gluino mass (why we think we’ll see it sooner than later)
The required cancellation is easier if the gluino mass is not “too large”.
susy – electroweak connection favors lighter gluinos
to avoid tuning (G. Kane et al)
look at models with nonuniversal gaugino masses

45. chargino/neutralino trilepton signature
If this signal is observed , the structure in the l+l-
mass distribution will constrain the c01 and c02
masses (difficult). LHC will take it from there.

46. stop signatures Aided by improved
CDF/D0 lepton coverage and heavy flavor tagging

47. colliders, SUSY and baryogenesis
since colliders will thoroughly explore the electroweak scale, we ought to be able to reach definite conclusions about EW baryogenesis
EW baryogenesis in SUSY appears very constrained, requiring a Higgs mass less than 120 GeV, and a stop lighter than the top quark
Baryogenesis requires new sources of CP violation besides the CKM phase of the Standard Model (or, perhaps, CPT violation).
B physics experiments look for new CP violation by over-constraining the unitarity triangle
SUSY models are a promising source for extra phases

48. such a light stop will be seen at the Tevatron

49.
LHC is a SUSY factory.
If LHC does not find SUSY forget about (weak scale) SUSY.
High rates for direct squark and gluino production.
Model independent measurement OK-
Model independent limit DIFFICULT.

50.
Use consistent model in simulations to study different cases.
Combinatorial SUSY is the dominant background to SUSY.
Guess and scan over the most difficult points of the multi-parameter-multi-model SUSY space.
Ultimately you want to measure all the parameters of the model.

51.
INCLUSIVE ANALYSES
Correlates well with

52. AN EVENT

53. -
h bb -1 SM
SUSY

54. - h bb SUSY@LHC Method works over a large region
of the parameter space in the SUGRA model
Contours show number of reconstructed Higgs
tanb=10
sgn m=+

57. There’s Something more About SUSY
The predicted value of sin2(qW(MZ))
~ (as(MZ)-0.118) (e.g. Ross et. al)
within 1% of measured value
The predicted upper limit on the higgs mass
~130 GeV (e.g. Carena et. Al, Ellis et. al …)
with 115 lower experimental limit things get urgent
EWSB through radiative corrections
the massiveness of the top quark

58. L. Alvarez-Gaume, J. Polchinski, M. Wise NPB221:495 (1983)
also L. Ibanez, and J. Ellis, D. Nanopoulos, K. Tamvakis the same year
Quote from the abstract: "We discuss the motivation for considering
models of particle physics based on N=1 supergravity...renormalization
effects drive spontaneous symmetry breaking of SU(2)xU(1) to U(1) for a
top quark mass between GeV."

59. The immediate future HEP hadron collider program
Run IIa
Run IIb
BTeV physics
LHC physics
Year:

60. Higgs

61. The wager
A light Higgs stabilized by TeV scale SUSY is what will be found.

62. something about terminology
Not everything super- has to do with supersymmetry. (superconductor, supermarket, superstition, supernatural etc…)
However, SUPERMAN does