there’s something about susy m. spiropulu efi/uofc
TRANSCRIPT
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)