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There’s Something About SUSY. m. spiropulu EFI/UofC. Something Heavy Supersymmetry is the most plausible solution of the hierarchy (issue) . about SUSY. Something Light low energy Supersymmetry is required . Something Dark might provide the missing matter of the universe

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There s something about susy

There’s Something About SUSY

m. spiropulu


About susy

Something Heavy

Supersymmetry is the most plausible solution of the hierarchy (issue) 

about SUSY

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)

There s something about susy


SUSY is not a (super)model

SUSY is a spontaneously broken spacetime symmetry

Bosons fermions i
bosons-fermions I

Bosons: Commuting fields

Integer spin particles

Bose statistics


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

Bosons fermions ii
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


















equal couplings

General mssm 370 parameters
general MSSM:370 parameters

There s something about susy

supersymmetry in colliders

 Tevatron mass reach: 400 – 600 GeV for gluinos,

150 – 250 GeV for charginos and


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.

Hierarchy of scales

16 orders of magnitude


What kind of physics generates and stabilizes the 16 orders of magnitude difference between these two scales

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

1027 eV 1011 eV 10-33 eV

Bosons fermions iii bose fermi cancellation
bosons-fermions IIIBose-Fermi Cancellation



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)

Unification of couplings

what’s up

with that?

unification of couplings

The gauge couplings of the Standard Model converge to an almost common value at very high energy.

Unification of couplings1

  • For MSUSY=1 TeV, unification appears at 3x1016 GeV

unification of couplings

  • SUSY changes the slopes of the coupling constants

There s something about susy

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

With r parity conservation
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.

Example of msugra susy
example of mSUGRA SUSY







More susy models
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

Susy mass clues
SUSY mass clues

Upper bound

(stau coanihilation)

TeVII reach

Red : most natural mass*





TeVII reach


TeVII reach

Mass (GeV/c2)





















* Anderson/Castano

There s something about susy

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

There s something about susy



Tevatron reach

LHC does the rest

already excluded


0.1 < Wc < 0.3

0.025 < Wc < 1

J. Feng, K. Matchev, F. Wilczek

There s something about susy

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


There s something about susy

CDF 300 GeV gluino candidate:

gluino pair strongly produced,

decays to quarks + neutralinos



p source

Main Injector

and Recycler



pp 14 TeV 1034

LHC (27 Km)

~2 x Tevatron (3.2 Km)

There s something about susy

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

There s something about susy

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

Missing e t mult ijets cdf



Missing ET + multijets(CDF)

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)

Fake met




Main Ring

Use to




“Fake” MET



eliminated with a set of timing and good jet quality requirements

& QCD mismeasurements

There s something about susy

Standard Model Missing Energy +jets

Z/W +jets

MC norm to

Z data


MC norm to

jet data

 top, dibosons

MC norm using theory cross section

There s something about susy



Number of High PT isolated tracks

0 >0

“blind analysis” approach

where you expect your signal

don’t look until you are ready

There s something about susy








comparisons around the “box”

There s something about susy

“The BOX”

The Box: SM Expected 76±13


in data


There s something about susy

“The other BOXes”

A/D SUSY boxes:

SM Expected 33±7


in data


There s something about susy

“The other BOXes”

SUSY box C:

SM Expected 10.6±1


in data


There s something about susy

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).

There s something about the gluino mass why we think we ll see it sooner than later

susy – electroweak connection favors lighter gluinos

to avoid tuning (G. Kane et al)

look at models with nonuniversal gaugino masses

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”.

There s something about susy

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.

There s something about susy

stop signatures

Aided by improved

CDF/D0 lepton coverage and heavy flavor tagging

There s something about susy

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

There s something about susy


  • 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.

There s something about susy


  • 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.

There s something about susy



Correlates well with

There s something about susy



There s something about susy





h bb


There s something about susy



h bb

Method works

over a large region

of the parameter space in the SUGRA model

Contours show number of reconstructed Higgs


sgn m=+

There s something more about susy
There’s Something more About SUSY

  • The predicted value of sin2(qW(MZ))

  • ~0.2314-0.25(as(MZ)-0.118)+0.002 (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

There s something about susy

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 55-200 GeV."

The immediate future hep hadron collider program

Run IIb

Run IIa

BTeV physics

The immediate future HEP hadron collider program


LHC physics

Year: 2002 03 04 05 06 07 08 09 10

The wager
the wager

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

Something about terminology

However, SUPERMAN does

something about terminology

Not everything super- has to do with supersymmetry. (superconductor, supermarket, superstition, supernatural etc…)

There s something about susy

Lord of the Rings The Two Towers

Run 152507 event 1222318

Dijet Mass = 1364 GeV (corr)

cos q* = 0.30

z vertex = -25 cm

J2 ET = 633 GeV (corr)

546 GeV (raw)

J2h = -0.30 (detector)

= -0.19 (correct z)

J1 ET = 666 GeV (corr)

583 GeV (raw)

J1 h= 0.31 (detector)

= 0.43 (correct z)

Corrected ET and mass are preliminary

(thanks to Rob Harris)

There s something about susy

  • RunIIa Luminosity Goals

    5-8 E31 cm-2/sec (w/o Recycler)

    10-20 E31 cm-2/sec (w/ Recycler)

    integrated: 2-5 fb-1 (2004)

  • RunIIb Luminosity Goals

    40-50 E31 cm-2/sec

    integrated: 15 fb-1 (2007)

    s(W), s(Z) ~10% higher

    s(tt) ~35% higher

  • The collider performance in Run II got off to a slow start.

  • The Beams Division made quick progress on the luminosity:

    • The peak luminosity increased from ~0.9E31 on 3/25/02 to ~1.8E31 by 5/10/02 to 3.6E31 by 10/5/02.

    • Many problems identified; some solutions found; some to be.

  • Still improving collider performance.

  • * For most of Run Ib, average luminosity at start of store was

  • ~1.6x1031 cm-2 s-1. Integrated luminosity delivered was ~0.15 fb-1.

There s something about susy

beamloading compensation

new injection helix

Step 13

AA->MI optics


There s something about susy

January 1 – June 1

  • Improve antiproton efficiency from Accumulator to Tevatron low-b

  • Improve proton intensity at Tevatron low-b

  • Commission Recycler parasitically

    June 3-14

  • Shutdown to install new Accumulator transverse core cooling

    June 15 – December 31

  • Improve stacking rate

  • Shutdown for continuing Recycler vacuum work (tentatively scheduled September 30-November 10)

  • Integrate Recycler into operations

  • Minimize access time

Underlying accelerator physics issues
Underlying Accelerator Physics Issues

  • Three primary accelerator physics issues are being dealt with:

    • Accumulator emittance/heating

      • Intrabeam scattering appears implicated as major source

    • Long range beam-beam in the Tevatron

      • Manifested as poor antiproton lifetime at 150 GeV

      • Once collision configuration achieved, this is not impacting performance

      • Contribution to lifetime from vacuum under investigation

    • Proton longitudinal emittance

      • Beamloading compensation implemented  some improvement, but appears to be growth during acceleration in Main Injector.

  • These issues interconnect many of the individual performance parameters

    Progress requires attacking everything in parallel.

Physics in run ii
Physics in Run II

  • Precision measurements, looking for an inconsistency with the Standard Model:

    • top quark and W boson properties

    • measurements of B mixing and CP parameters

  • Possible discoveries include the Higgs boson or any new physics at the Tevatron mass scale:

    • Higgs boson

    • Supersymmetry

    • Extra dimensions

    • New dynamics (technicolor, new gauge bosons)

    • Quark or lepton compositeness.

Prospective physics highlights at 0 1 0 3 fb 1

0.1 fb-1

Even witha data sample of this size, there will be many new physics results.

New detectors have increased capability

Ecm changed from 1.80 to 1.96 TeV, significantly increasing cross sections for high-mass states.

Production of top, bottom, and charm quarks, W and Z, jets

B Physics: Start of a broad program: spectroscopy, lifetimes, and mixing

0.3 fb-1

Major new results in every area

Top quark: Mass measurement with twice current precision

CP violation: Bs mixing to xs = 25

New physics searches:

Extra dimensions with scale of 1.6 TeV

Confirmation or elimination of new physics indicated by Run I observation of rare events

QCD: Jet spectrum at highest transverse energy

Prospective physics highlights at 0.1-0.3 fb-1

Prospective physics highlights at 1 2 fb 1

1 fb-1


W magnetic moment, signals for WW and W+Z production

top quark properties with 1000 top events per experiment


possible signals in trileptons

SUSY Higgs signal for m(A) ~ 100 GeV, tan b= 35

B Physics

Lb lifetime to 0.06 ps

2 fb-1


W boson massmeasured to greater precision than from LEP

top quark mass to 2.7 GeV/expt


95% exclusion of Higgs boson with mass of 115 GeV


observe squarks and gluinos if gluino masses below 400 GeV

observe chargino/neutralinos if mass below 180 GeV, tanb = 2

CP violation and Bottom quark

Measurement of decay mode BdgK*m+m- with 60 events

Bs mixing to xs = 40

Prospective physics highlights at 1-2 fb-1

Prospective physics highlights at 4 8 fb 1

4 fb-1

Higgs: 95% exclusion of standard Higgs boson up to 125 GeV


discovery of supersymmetry in large fraction of parameter space for minimal supersymmetry

discovery of SUSY Higgs for m(A)~150 GeV, tanb = 35

8 fb-1


3s evidence for standard Higgs with mass less than 122 GeV

95% exclusion of standard Higgs for masses below 135 GeV or from 150-180 GeV


95% exclusion of the minimal supersymmetric Higgs in the maximal mixing model

Prospective physics highlights at 4-8 fb-1

Prospective physics highlights at 15 fb 1
Prospective physics highlights at 15 fb-1

  • Higgs

    • 4-5s evidence for standard Higgs with mass of 115 GeV

    • 95% exclusion of standard Higgs for all masses below 185 GeV

  • Supersymmetry

    • SUSY trilepton signal extended to large tanb and gluino masses 600-700 GeV

    • possible discovery of supersymmetric Higgs boson m(A) up to 200 GeV, tanb = 35

  • Electroweak

    • top quark mass measurement with error of 1.3 GeV/expt

    • W mass measurement with error of 15 MeV/expt

Cdf ii detector is recording quality data ichep 2002
CDF-II detector is recording quality data (ICHEP 2002)

  • Stable physics running established in early 2002

    • intensive effort during fall 2001 shutdown had big payoff

    • silicon coverage, trigger came together very quickly

      > 95% / 90% / 80% of L00/SVX/ISL now (summer 2002) regularly read out

      L1/L2/L3 trigger 6400/145/25Hz @1.6E31, <1% deadtime (BW 40K/300/70)

    • trigger algorithms increased rapidly in sophistication; now quite stable

      ~140 separate trigger paths (e, m, t, n, g, jet, displaced track, b jet, …)

  • 33.0/pb delivered; 23.5/pb recorded January-June 2002

    • ~10.0/pb pass the most stringent analyses’ “good run” criteria

Cdf ii detector
CDF II Detector

All critical components are working well

132 ns front end

COT tracks @L1

SVX tracks @L2

40000/300/70 Hz

~no dead time

7-8 silicon layers

rf, rz, stereo views

z0max=45, max=2


Double b tags essential

for Mtop, Hbb

TOF (100ps@150cm)

30240 chnl, 96 layer

drift chamber

s(1/pT) ~ 0.1%/GeV

s(hit) ~ 150mm

 coverage

extended to


Tile/fiber endcap

calorimeter (faster,

larger Fsamp, no gap)

Cdf ii detector1
CDF II Detector

  • Major qualitative improvements over Run 1 detector:

    • Whole detector can run up to 132 nsec interbunch

    • New full coverage 7-8 layer 3-D Si-tracking up to |h| ~ 2

    • New faster drift chamber with 96 layers

    • New TOF system

    • New plug calorimeter

    • New forward muon system

    • New track trigger at Level 1 (XFT)

    • New impact parameter trigger at Level 2 (SVT)

  • All systems working well

    • Silicon and L2 took longer to commission

Forward region restructured

There s something about susy

  • Taking good quality data during 2002

  • Many new capabilities of detector and trigger

    • Each Run II pb-1 worth much more than each Run I pb-1!

    • And of course 9% more W,Z; 35% more tt at 1.96 TeV

  • Many early physics results

    • sB(Wln), sB(W mn) / sB(Z mm)

    • m(B), t(B), DM(Ds,D+), BR(D0 KK,pp)

  • Tooling up for MW, Mtop, SUSY searches, Higgs search

Run iib
Run IIb

  • Additional luminosity provides greater precision for electroweak measurements, greater reach for exotic searches, plus the opportunity to observe a low-mass Higgs boson.

  • Accelerator

    • Improve luminosity by factor of 2-3 with a number of modest upgrades.

    • Accelerator advisory committee reviewing progress.

    • Right now, the attention must be concentrated on run IIa.

  • Detectors

    • Two upgrade projects:

      • Replace partly rad-damaged silicon detectors with new detectors of simpler design with more rad-hard technology.

      • Upgrade data acquisition and triggers to deal with higher luminosity.

    • PAC has been following projects, Stage 1 approval discussion at Aspen

There s something about susy

if this is new physics, it is probably SUSY, and the Tevatron will confirm it.

if it is not new physics, it constrains susy models significantly

There s something about susy

There s something about susy

two events are real CDF Can you

data and one is graviton

simulation; Can you

pick the graviton?

There s something about susy

good news for Can you

the Tevatron

mSUGRA Can you

LSP gives rise to missing energy signatures

Higgs sector
Higgs Sector Can you

There s something about susy

good news for Can you

direct searches, too!

There s something about susy

sneutrino dark matter Can you

if sneutrinos are the LSP, they are dark matter

but there are problems:

LEP measurement of the invisible width of the Z boson

implies M_sneutrino > 45 GeV

but then expect low abundance due to rapid annihilation

via s-channel Z and t-channel neutralino/chargino exchange.

There s something about susy

sneutrino dark matter Can you

L. Hall et al (1997): susy with lepton flavor violation can split

the sneutrino mass eigenstates by ~> 5 GeV, enough

to suppress the annihilation processes

however, the same interaction seems to induce at

least one neutrino mass ~> 5 MeV.

this is now excluded completely by SuperK + SNO +

tritium beta decay.

it appears that sneutrinos are ruled out as the

dominant component of CDM

There s something about susy

gravitino dark matter Can you

Large classes of susy models, i.e. gauge-mediated and

other low-scale susy breaking schemes, produce light

(keV) gravitinos that overclose the universe.

Fujii and Yanagida have found a class of

“direct” gauge mediation models where the decays

of light messenger particles naturally dilutes the

gravitino density to just the right amount!

Such models have distinctive collider signatures

There s something about susy

Kaluza-Klein dark matter Can you

If we live in the bulk of the extra dimensions,

then Kaluza-Klein parity (i.e. KK momentum)

is conserved.

So the lightest massive KK particle (LKP) is stable

Could be a KK neutrino, bino, or photon

There s something about susy

How heavy is the LKP? Can you

Current data requires MLKP ~> 300 GeV

LKP as CDM requires MLKP ~ 650 –850 GeV

the LHC collider experiments will certainly see this!

There s something about susy

the Bigger Big picture Can you

The Standard Model describes everything that we have seen to extreme accuracy.

Michelangelo Antonioni on Ferrara:

“ is a city that you can only see partly

and the rest disappears and can only

be imagined...” (beyond the clouds)

There s something about susy

the Bigger Big picture Can you


(even) extra dimensions


Ian Shipsey

Now we want to extend the model to higher energies and get the whole picture

For this we need new experiments and ideas

There s something about susy

Space and time may be doomed. Can youE. Witten

I am almost certain that space and time

are illusions. N. Seiberg

The notion of space-time is clearly something we’re

going to have to give up.A. Strominger

If you ask questions about what happened at very early times, and you compute the answer, the answer is: Time doesn’t mean anything. S. Coleman

There s something about susy

D. Gross Can you

There s something about susy

SCIENCE: The Glorious Entertainment Can you

…for any important assertion evidence must be produced;

…prophecies and bugaboos must be subjected to scrutiny;

… guesswork must be replaced by exact count;

….accuracy is a virtue and inquiry is a moral imperative

To the hegemony of science we owe a feeling for which there is no name, but which is akin to the faith of the innocent that the truth will out and vindication will follow. In its purest form science is justice as well as reason.

Jacques Barzun

Dm at colliders eg lhc
DM at colliders (eg LHC) Can you

  • M0=100 GeV

  • M1/2=300 GeV

  • 0 almost pure Bino

    Will be able to predict

    within 20% Wc h2

    However no strict useful upper

    bound from Wc h2 <0.5

    show feng matchev plot

What will we learn at colliders
What will we learn at colliders Can you

Does low energy SUSY exist (discovery)

Measure the parameters and SUSY masses

Figure out how SUSY is broken

Is R-Parity violated

IS THE dm susy?

There s something about susy

A proton/antiproton beam is a broadband beam of quarks, antiquarks and gluons.

Total longitudinal momentum is unknown.

Total trasnverse momentum is zero

Total transverse momentum of invisible particles inferred from visible transverse momentum.

History lines
HISTORY-LINES antiquarks and gluons.

There s something about susy

R-parity violating scenarios antiquarks and gluons.

Deliot et al.

Resonant sneutrino/slepton production

There s something about susy

Example antiquarks and gluons.

10 fb-1

smass reconstruction


Booster antiquarks and gluons.

p source

Main Injector

and Recycler


Super models
Super-Models antiquarks and gluons.


mSUGRA input

Summary of runii sugra workshop
Summary of RUNII SUGRA Workshop antiquarks and gluons.


With 2 fb-1

m1/2 up to 150 GeV

for m0~200 GeV


With 2 fb-1

L 50-100 TeV

for m( )~200-300 GeV


There s something about susy

Getting the SUSY scale antiquarks and gluons.





There s something about susy

Getting the SUSY scale antiquarks and gluons.

 1000 fb-1

100 fb-1

10 fb-1