There’s Something About SUSYThere’s Something About SUSYm. m.

spiropuluspiropuluEFI/UofCEFI/UofC

about SUSYSomething Heavy

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

Something Lightlow energy Supersymmetry is required

Something Darkmight provide the missing matter of

the universeif the lightest neutralino is stable

Something Urgenttestable at high enough energies (now)

Something Beautifulthe symmetry between fermions and

bosons

Something Exotica component of string theory

Something Coolthey couple with known and sizable

strengths

SUSY is not a (super)model

SUSY is a spontaneously broken spacetime symmetry

SUSYSUSY

bosons-fermions IBosons: 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

bosons-fermions IIIf we Taylor expand an electron (anticommuting field) in the extra coordinates

selectron field in superspace = selectron(boson) + electron(fermion)

For each boson of spin J there is a fermion of spin J±½ of equal mass

quark

quark

gluon

quark

squark

gluino

PhotonW,Zgluon

Squarkslepton

PhotinoWino,Zinogluino

quarklepton

equal couplings

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 bunchmore of what are called “soft breaking terms”: the masses of all the superparticles.

general MSSM:370 parameters

M1M2M3

particle content

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 theelectroweak scale, we will discover sparticles soon.

hierarchy of scales

10-33 cmPlanck scale

GN ~lPl2 =1/(M1/(MPlPl))22

10-17 cmElectroweak scale

range of weak forcemass is generated (W,Z)

strong, weak, electromagneticforces have comparable strengths

1028 cmHubble scale

size of universe lu16 orders of magnitudepuzzle

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

1027 eV 1011 eV 10-33 eV

bosons-fermions IIIBose-Fermi Cancellation

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)

SUSY

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

what’s upwith that?

unification of couplings

SUSY changes the slopes of the coupling constants

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

proton’s (don’t) decay (fast)

In generic SUSies the proton could decay

Satisfy this by conserving R-parity R=(-1)3(B-L)+2S

We have measurements to the contrary effect

with R-parity conservation

370107 (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.

squarks/sleptons gauginos higgses

example of mSUGRA SUSY

tanA

example collider signatures

example backgrounds

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 cluesM

ass

(GeV

/c2 )

01

~ 1

~ Re~ R~ R~ ~ Rl~ t~ b

~ q~ g~

Upper bound(stau coanihilation)

190170

220

D0

D0

CDF

CDF

CDF

D0CDF

D0 GMSB

45DM

LEP2

LEP2

LEP2

97LEP2

LEP2

LEP2

LEP2 LEP2

LEP2

LEP2 GMSB

LEP2

TeVII reachTeVII reach

TeVII reach

Red : most natural mass*

* Anderson/Castano

Cosmology needs sources of non-baryonic dark matter SUSies provide weakly interacting massive particles to account for the universe’s missing mass

neutralinosneutralinos

sneutrinossneutrinos

gravitinosgravitinos

We are closing in fast on either discovery or exclusion!

There is a good complementarity between direct, indirect, and collider searches

the dark side of SUSY

already excluded

CDMS, CRESST,GENIUS

GLAST

Tevatron reach

J. Feng, K. Matchev, F. Wilczek

LHC does the rest

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.

01χ~

01χ~

CDF 300 GeV gluino candidate:

gluino pair strongly produced,decays to quarks + neutralinos

detectors

DD

~2 x Tevatron (3.2 Km)

LHC (27 Km)

Main Injectorand Recycler

p source

Booster

Teva

tron

Teva

tron

pp 14 TeV 1034

32105 TeV 2 pp

machines

gluino decay path example

example cross sections

B L tNobserved

L is the Luminosity is the acceptance (trigger included)B is the Background

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

(ppX)=70 mb

Run I L ~ 1031 crossings/cm2/sec

N/sec ~ L = 7x105/sec

>1 interactions per beam crossing!

Cross Section for top production: (pptt+X)=70 mb

This is around 1/1010 of total

N/sec ~ L = 7x10-5/sec

A couple were created/day but we only

saw a small %

~100 events in 3 ys in two experiments

recording the physics: triggering

recording the physics: triggering

recording the physics: triggering

• Calorimeter energyCentral Tracker (Pt,)Muon stubs

Cal Energy-track match E/P, Silicon secondary vertexMulti object triggers

Farm of PC’s runningfast versions of Offline Code moresophisticated selections

Missing Energy provides R-parity conserving SUSY signatures (R=(-1)3B+L+2S) and also appears

in many other phenomenological paradigmsMET + 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)

iiiT n)(EE ˆsin

|P| max T

Missing ET + multijets (CDF)

01χ~

01χ~

Production/Decay GraphsProduction/Decay Graphs

MAIN RING DETECTOR NOISE COSMICS eliminated with a set of timing and good jet quality requirements

“Fake” MET cosmic

QCD gap

Main Ring

& QCD mismeasurements

Use todefinefiducial

jets

Standard Model Missing Energy +jets

top, dibosonsMC norm using theory cross section

QCD MC norm tojet data

Z/W +jets MC norm to Z data

Number of High PT isolated tracks

0 >0

“blind analysis” approachwhere you expect your signaldon’t look until you are ready

Analysis

HT=

ET(2

)+E

T(3

)+M

ET

Optimization for SUSYOptimization for SUSY

comparisons around the “box”

QCD

Z(inv)

W(,e)top

W()

““The BOX”The BOX”

The Box: SM Expected 76±13

Foundin data

74

““The other BOXes”The other BOXes”

A/D SUSY boxes:SM Expected 33±7

Foundin data

31

““The other BOXes”The other BOXes”

SUSY box C:SM Expected 10.6±1

Foundin data

14

LIMITSLIMITS

Candidate Event

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

...7.1 21

22

23

2Z 0.014M0.24M7.2MM

The required cancellation is easier if the gluino mass is not “too large”.

802.7

300 2Z

23

3 MM

M

There’s Something About the gluino mass (why we think we’ll see it sooner than later)

susy – electroweak connection favors lighter gluinosto avoid tuning (G. Kane et al)

look at models with nonuniversal gaugino masses

If this signal is observed , the structure in the l+l-mass distribution will constrain the 0

1 and 02

masses (difficult). LHC will take it from there.

Batavia TeV, 2 , spp

chargino/neutralino trilepton signature

Aided by improved CDF/D0 lepton coverage and heavy flavor tagging

stop signatures

Batavia TeV, 2 , spp

colliders, SUSY and baryogenesis

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

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

such a light stop will be seen at the Tevatron

LHC is a SUSY factory.LHC is a SUSY factory.

If LHC does not find SUSY forget about If LHC does not find SUSY forget about (weak scale) SUSY.(weak scale) SUSY.

High rates for direct squark and High rates for direct squark and gluino production.gluino production.

Model independent measurement OK- Model independent measurement OK-

Model independent limit DIFFICULT. Model independent limit DIFFICULT.

SUSY@LHCSUSY@LHC

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.

SUSY@LHCSUSY@LHC

Correlates well with

TTTTT EPPPP )4()3()2()1(

),min( ~~ guSUSY MMM

SUSY@LHCSUSY@LHC

SUSY@LHCSUSY@LHC

t t

bbhh

suppress to

1.0DR lepton, isolated-non

GeV 100 P with

jets additional least twoat

GeV 55Pwith

jets-b taggedoexactly tw

GeV300E

:Require

events SUSY of 20%in

then ~~ If

bb

T

T

T

01

02

-1

SMSUSY

SUSY@LHCSUSY@LHC

Geneva TeV, 14 , spp

tan=10sgn =+

Method worksover a large regionof the parameter space in the SUGRA modelContours show number of reconstructed Higgs

SUSY@LHCSUSY@LHC

SUSY@LHCSUSY@LHC

SUSY@LHCSUSY@LHC

There’s Something more About SUSY

• The predicted value of sin2(W(MZ))~0.2314-0.25(s(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 correctionsthe massiveness of the top quark

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 consideringmodels of particle physics based on N=1 supergravity...renormalizationeffects drive spontaneous symmetry breaking of SU(2)xU(1) to U(1) for atop quark mass between 55-200 GeV."

The immediate future HEP hadron collider program

Year: 2002 03 04 05 06 07 08 09 10

Run IIaCollider: Run IIb

BTeV physics

LHC physics

Higgs

the wager

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

something about terminologyNot everything super- has to do with supersymmetry. (superconductor, supermarket, superstition, supernatural etc…)

However, SUPERMAN does

Lord of the Rings The Two TowersRun 152507 event 1222318

Dijet Mass = 1364 GeV (corr)

cos * = 0.30

z vertex = -25 cm

J1 ET = 666 GeV (corr)

583 GeV (raw)

J1 = 0.31 (detector)= 0.43 (correct z)

J2 ET = 633 GeV (corr)

546 GeV (raw)

J2 = -0.30 (detector)= -0.19 (correct z)

Corrected ET and mass are preliminary

(thanks to Rob Harris)