Experimental Searches for SUSY at the Tevatron

Experimental Searches Experimental Searches for SUSY at the Tevatronfor SUSY at the Tevatron

Monica D’OnofrioIFAE-Barcelona

On behalf of the CDF and DØ collaborationsOn behalf of the CDF and DØ collaborations

SUSY’09SUSY’09 , , Boston, USA, June 5-10, 2009Boston, USA, June 5-10, 2009

The TevatronThe Tevatron

Monica D'Onofrio, IFAEExperimental Searches for SUSY at the

Tevatron, 6/5/09 2

Proton-antiproton: √s = 1.96 TeV

Typical (peak) initial inst. Luminosity ~ 3.3 (3.5)*1032 cm-2 s-1

Integrated Luminosity/week(month) ~ 75 pb-1/(260 pb-1)

Highest-energy accelerator currently operational performing very well!

p p_

CDF

DØ

Delivered: 6.8 fbDelivered: 6.8 fb-1-1

Fermilab

Integrated luminosity per year

Peak luminosity

year: ‘02 ‘03 ‘04 ‘05 ‘06 ‘07 ‘08 ‘09

CDF and CDF and DØDØ in RunIIin RunII


Tevatron, 6/5/09 3

DØCDF

Took > 1 year of collisions to get to stable high efficiency

(80-90%)

Supersymmetry in 30’’Supersymmetry in 30’’


Tevatron, 6/5/09 4

SUSY: New spin-based symmetry relating fermions and bosons:

Naturally solves the hierarchy problem

Q|Boson> = Fermion

Q|Fermion> = Boson

Define R-parity = (-1)3(B-L)+2s

R = 1 for SM particles R = -1 for MSSM partners

gaugino/higgsino mixing

If conserved, provides Dark Matter Candidate

(Lightest Supersymmetric Particle)

No SUSY particles found yet SUSY must be broken > 100 parameters even in “minimal”

models

The Standard Model is theoretically incomplete Require fine tuning, account only for 4% of energy in Universe ….

Searching for SUSYSearching for SUSY


Tevatron, 6/5/09 5

Signature-based searches: Search for unusual final states with specialized analysis Optimize selection to reduce backgrounds Interpret the results in several models (GMSB, AMSB, RPV-

SUSY etc.)

Model-inspired searches: Explore large regions of parameter space Theory driven: constrained MSSM models used as benchmark mSUGRA, GMSB, etc.

Global searches: Maximize parameter space coverage Less sensitivity but could give hint of deviation from SM

predictions

The breaking mechanism determines the phenomenology and the search strategies

OutlineOutline “Standard SUSY” searches

mSUGRA-inspired: chargino/neutralino Squarks and gluinos

GMSB-inspired: Chargino/neutralino

“Non-Standard SUSY” searches Bs RPV SUSY (sneutrinos) Long-Lived Particles SUSY Hidden Valleys

Not only SUSY ..

Summary and Conclusions


Tevatron, 6/5/09 6

CDF: http://www-cdf.fnal.gov/physics/exotic/exotic.html

DØ: http://www-d0.fnal.gov/Run2Physics/np/

SUPE

R

Standard SUSY searches: Standard SUSY searches: mSUGRAmSUGRA


Tevatron, 6/5/09 7

(p

b)

m (GeV)

0,6tan,300

300,100

0

2/10

A

GeVmGeVm

mixing of 3rd generation

leads to light stop,sbottom and stau mass

Squarks andgluinos heavy 1st and 2nd

generation squarks are mass degenerate

Light gauginosalso expected

mSUGRA provides a good reference model (5 parameters) Consider production with highest cross sections

Small masses (chargino/neutralinos) or large couplings (squark/gluino)

Final states depend on sparticle mass hierarchy and mixing (low/high tan)

0,4tan,300

150,100

0

2/10

A

GeVmGeVm

0022 ±±

1 1 production: “trileptons” production: “trileptons”

Monica D'OnofrioExperimental Searches for SUSY at the

Tevatron, 6/5/09 8

Assume RP conservation, 01 is LSP

Low cross sections (σ x Br < 0.5 pb) Very clean signature:

Missing ET due to undetected 01

3 isolated leptons

Main backgrounds: WW, WZ Drell-Yan, W+jets, ttbar

Rejection using kinematic selections on: Ml+l-, N jets, Missing ET, between leptons...

• 3 identified leptons (e,)• 2 identified leptons + track (l)• “Tight” and “loose” e, categories

• 2 identified leptons + track (l)•+ l and (had decay)•“low-pT” and “high-PT” searches

• 3 identified leptons (e,)• 2 identified leptons + track (l)• “Tight” and “loose” e, categories

• 2 identified leptons + track (l)•+ l and (had decay)•“low-pT” and “high-PT” searches

3.2 fb-1

2.3 fb-1

~

~

~~ ~~

0022 ±±

1 1 in trileptons: results in trileptons: results


Tevatron, 6/5/09 9

DØ (2.3 fb-1)Channel SM expected

Data

CDF (3.2 fb-1)Channel SM expected

Data

Low pT 5.4 0.6 9

Trilepton 1.5 0.2 1

High pT 3.3 0.4 4

Lepton+trk 9.4 1.2 6

Good agreement between data and SM prediction set limit

[email protected] fb-1 results in PRL 101, 251801 (2008)

CDF excludes m±1

< 164 (155 Exp.)

GeV/c2

in the same scenario (with 2.3 fb-1)

DØ excludes m±1

< ~155 (160 Exp.)

GeV/c2

arXiv:0901.0646 (sub.to PLB, 2009)

Study dependency on other parameters - exclude 1

± of 130 GeV/c2 up to tan β =9.6

New!

CDF @ 2 fb-1

m0 = 60 GeV, tan 3, A0=0, >0m0 = 60 GeV, tan 3, A0=0, >0

~~ ~~

~

~ ~

0022 ±±

1 1 in trileptons: resultsin trileptons: results


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excluded region in mSUGRA m0-m½ space

Key-points: • Lepton coverage in -selection • Luminosity: ~10-20 GeV/c2 gained per 1 fb-1

Key-points: • Lepton coverage in -selection • Luminosity: ~10-20 GeV/c2 gained per 1 fb-1

Use common benchmark scenario: tan(β)=3, A0=0, μ>0

New!

Limits depend on relative -l

masses m2 > ml increases BR to e/ m2 ≈ ml reduces acceptance

to lowest-pT lepton

~~ ~~

~~

~~ ~

~

HeavyHeavy0022 ±±

1 1 production production


Tevatron, 6/5/09 11

Assume: m(20,1

±) > m(10)+m(W,Z)

Final state: e+e- pairs (Z), at least 2 jets (W) and Missing ET (> 40, 50, 60 GeV)

Main Background: Z+jets

observed cross sections ~ 1-3 pb

Missing ET > 40 GeV: Data: 7, SM Expected: 6.41 ± 0.95

M0 = 1000 GeV tan β= 10, >0

M0 = 1000 GeV tan β= 10, <0

W, Z bosons on shell

86 < Me+e- < 97 GeV/c2

60 < Mdijet < 95 GeV/c2

New!

L=2.7 fb-1

~~ ~~~~~

Search for squarks and gluinosSearch for squarks and gluinos


Tevatron, 6/5/09 12

Search for squark and gluino pair production in final states with 2, 3, or 4 jets and Missing ET 2 jets + ET : qq → qq1

010 (mq < mg)

3 jets + ET : qg → qqq101

0 (mq ~ mg) 4 jets + ET : gg → qqqq1

010 (mq > mg)

Similar results for CDF and DØ, probing sparticle masses ~ 400 GeV/c2

~ ~~ ~~ ~~ ~

~ ~~ ~

~ ~~ ~~ ~~ ~

~ ~~ ~

PLB 660, 449 (2008) PRL 102, 121801 (2009)

Squarks in Squarks in , jets and Missing E, jets and Missing ETT


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Assume large mixing scenario:• 1 is Next-LSP (“tau-corridor”)• m(g)>>m(q) qRqL dominates

Final states: • ≥ 2 Jets + Missing ET + ≥ 1 (hadronic decay)

Perform 2 analysis (-dijet, -multijet), then combined Optimization on Missing ET and ST = pj1

T + pj2T + E

T

~

Observed: 2 events Exp.: 1.7 0.2 (stat.) +0.6

-

0.3(syst.)

~ ~ ~ ~

Further combined with inclusive squark/gluino analysis in 2/3 jets final states: Exclude m(q) < 410 GeV

~

arXiv:0905.4086 Sub. to PLB

New!

g-mediated b productiong-mediated b production


Tevatron, 6/5/09 14

~~ ~~

Light sbottom in large mixing scenarios Dedicated searches for b production If m(b)<m(g) (assuming B.R.bb100%)

Search for b from gluino decays (gg ~ 10 bb)

~

~

~

~~ ~~

~~

2 optimization regions depending on g-b mass difference

~~

Final state: Missing ET + 4 b-jets

Use b-tagging algorithm to identify at least 2 b-jets

2 Neural Network to reject background (top and QCD-multijets)

PRL 102, 221801 (2009)

Stop searches Stop searches


Tevatron, 6/5/09 15

Lightest of the squarks

Can be lighter than the top quark due to the large SM top mass

2-, 3-body decays possible

Assumptions for stop searches at the Tevatron: Rp conservation, mstop< mtop

(a) 2-body: if and

(b) 2-body: if allowed

(c) 3-body:

011

~~ ct

vblt ~~1

11

~~mmm bt 1

01~~mmmm bWt

011~~~ bWbt

(a) (b) (c)

Stop searches: Stop searches:


Tevatron, 6/5/09 16

Assume 100% B.R. Mass 0

1 in range [45-90] GeV Signature: 2 jets (at least one c-tagged) and Missing ET

011

~~ ct

Stop masses excluded up to 150 GeV/c2 if m(t)-m(01)>60

GeV/c2

~ ~

PLB 665, 1 (2008)

~

New results expected soon!



Tevatron, 6/5/09 17

11~~ bt

Assume on-shell charginos: Signal topology depends on m = mt1 - m

Signature: Missing ET + 2 opposite-sign leptons + 2 b-jets (0 or ≥ 1 tag)

Main background: top production (dilepton) Reconstruct stop mass with a kinematic fit.

bt mmm 11~~

Limits for several dilepton BR for 115 < m(t1)<197 GeV, 44 <m(0

1)< 91 GeV. Fix to m(±1) =105.8 and

125.8 GeV

New!

~ ~



Tevatron, 6/5/09 18

vblt ~~1

Assume sneutrino is LSP Signal topology depends on m = mt1 - m

Signature: Missing ET + 2 opposite-sign leptons + 2 b-jets CDF (1 fb-1): ee, e, ,DØ (1 fb-1):

ee, e

ee+e+

For large m: mt1 < 175 GeV (DØ)mt1 < 180 GeV (CDF)

~ ~

PLB 675, 289 (2009)New

!

~ ~

~~

GMSB: GMSB: 0022 ±±

1 1 in in + Missing E+ Missing ETT


Tevatron, 6/5/09 19

G~~0

1

SUSY breaking at scale (10 -100 TeV) Squarks, gluinos and sleptons heavy Gravitino very light (<< MeV) and LSP Neutralino or slepton can be NLSP If NLSP is neutralino

In Rp conservation scenario: 2 NLSP 2+ MET (+X) final states

Assume 01 (NLSP) short-lived

Optimize the +MET analysis for 0 ns lifetime

Significant Missing ET and Large HT

HT = (EM objects) + ETjets +

Missing ET

Very low SM background Z , W l

New!

~~ ~~

0022 ±±

1 1 in in + Missing E+ Missing ETT : results : results


Tevatron, 6/5/09 20

Limits on neutralino mass VS lifetime

No excess observed

Mass(01)>149 GeV/c2 for ≤

2 ns (Expected: M(0

1)>141 GeV/c2)

New!

““Non-Standard” SUSY SearchesNon-Standard” SUSY Searches


Tevatron, 6/5/09 21

Indirect searches: Bs Indirect searches: Bs


Tevatron, 6/5/09 22

Sensitive to new physics: SUSY particles show up in loops (or direct decays if Rp violation)

SM: BR = 3.42 10-9

SUSY enhance ~(tan)6

CDF (2 fb-1): Br(Bs→)<5.8×10-8 @

95% CLDØ (2 fb-1): Br(Bs →)<9.3×10-8 @

95%CL

Expected Limits at 5 fb-

1(DØ): Br(Bs →)<5.3×10-8 @

95%CL

Unofficial CDF/DØ comb.: Br(Bs →)<4.5×10-8

New!

Expected Limits at 3.7 fb-

1(CDF): Br(Bs →)<3.3×10-8 @

95%CL

Search for scalar neutrinosSearch for scalar neutrinos


Tevatron, 6/5/09 23

Assume RP violation: possible production of single SuperPartner

Search strategy: look at high-mass unlike flavored lepton pairs: e(DØ), eehh (CDF)

probe the ijkMsneutrino parameter space

Update of PRL 100, 241803 (2008) (1. fb-1)

L=1 fb-1

Mass()=500 GeV/c2

σ x BR upper limits of 0.018 pb (eμ), 0.037 pb (eτ), 0.052 pb (μτ) for m() = 800 GeV (with λ'311 = 0.1, λ132=λ133= λ231=0.05)

limits on the σ x BR and RPV couplings λ’311 × λ312

for different sneutrino masses.

~

~

Charged massive stable particlesCharged massive stable particles


Tevatron, 6/5/09 24

Long-lived charginos are expected in some AMSB models

with a “wino-LSP” (small – 10 mass difference)

They would appear like slowly-moving muons

Make use of the time of flight information

CDF: Interpretation for strongly interacting charged massive particles,such as stops with a small stop- mass difference m(stop) > 250 GeV

DØ: interpretation for charged gauginos (higgsinos)

m > 206 GeV

m > 171 GeV

PRL 102 , 161802 (2009 )

arXiv:0902.1266 acc. by PRL

Supersymmetric Hidden ValleysSupersymmetric Hidden Valleys


Tevatron, 6/5/09 25

Mass

GeV

TeV

Visible sector

Hidden sector

SM

SU

SY

Dark

SU

SY

Mess

enger(

s)Phenomenology of SUSY HV similar to GMSB • Cascade to visible LSP• LSP decays into hidden sector

• Photon + dark LSP (X = darkino)• Dark photon(D )+ X (Missing ET)

• Dark photon (~GeV) decays into fermions• BR (0

1 /D X): free parameters

Hidden valley (HV) models: weakly coupled sector Motivated by recent results from PAMELA, ATIC, EGRET, FERMI-LAT,

HESS…

Final State: Missing ET, , a pair of spatially close leptons

Optimize for m(D) < 2.5 GeVnever been

investigated!

~~

~

SUSY Hidden Valley: resultsSUSY Hidden Valley: results


Tevatron, 6/5/09 26

Main background: Multijet events with

real/misidentified photons Wlwith real/misidentified

photons Set limits on chargino mass as a

function of the dark photon mass and BR(0

1 /D X):

m(D) = 1.4 GeV

arXiv:0905.1478 sub. to PRL

New!

~

BR=0.5

Search for t’

Not only SUSY …Not only SUSY …


Tevatron, 6/5/09 27

Many more models explored by CDF/DØ Extra-Dimensions, Lepto-quarks , New gauge bosons, 4th gen. b/t quarks, Compositness, Hidden Valleys …

Many more models explored by CDF/DØ Extra-Dimensions, Lepto-quarks , New gauge bosons, 4th gen. b/t quarks, Compositness, Hidden Valleys …

RS Graviton (m<944 GeVfor k/mp=0.1)

Search for G*, Z’, W’ in DiBoson Resonances

Search for B’

Search for 1st generation LQ in ejej

..and global searches carried out looking for the unknown

Search for high-mass narrow resonances in the diEM channel

RS Graviton (m<767 GeVfor k/mp=0.1)SM Z’ (m<944 GeV)

m(B’) < 325 GeV

m(t’) < 311 GeV

m(LQ) < 292 GeV

Tevatron BSM Searches @ SUSY09 Tevatron BSM Searches @ SUSY09


Tevatron, 6/5/09 28

Biscarat Searches for Squarks and Gluinos Using Data from D0 Bhatti Search for Supersymmetry signatures in events with jets or photons at CDF Besancon Search for Charginos and Neutralinos with the D0 detector Strologas Search for trilepton SUSY signal at CDF Ivanov Searches in Dilepton Final States at CDF Ferapontov Searches for Extra Dimensions and for Heavy Resonances in Leptons, Photons, and MET Final States at D0 Goncharov Searches for extra dimensions at CDF Yoo Search for Anomalous Top Quark Production at D0 Moed Top Quark Production (including single top) at CDF Jabeen Search for New Physics Contamination in the Top Quark Samples at D0 Barfuss Searches for Leptoquark production in p p-bar collisions at the D0

experiment Johnson Search for Neutral Long-lived Particles Decaying to b-bbar at D0 Xie Search for Charged Massive Long-Lived Particles Using Data from D0 Culbertson Rare and exotic processes at CDF Gold Searches for new massive vector bosons with CDF Kraus Model Independent Search for New Physics in Leptonic Final States at D0 Gershtein Search for Hidden Valleys with Photons at D0 Ruiz-JimenoRecent results on Bs→μμ and other FCNC decays from the CDF experiment Mackin Search for the Lightest Scalar Top Quark at D0

Biscarat Searches for Squarks and Gluinos Using Data from D0 Bhatti Search for Supersymmetry signatures in events with jets or photons at CDF Besancon Search for Charginos and Neutralinos with the D0 detector Strologas Search for trilepton SUSY signal at CDF Ivanov Searches in Dilepton Final States at CDF Ferapontov Searches for Extra Dimensions and for Heavy Resonances in Leptons, Photons, and MET Final States at D0 Goncharov Searches for extra dimensions at CDF Yoo Search for Anomalous Top Quark Production at D0 Moed Top Quark Production (including single top) at CDF Jabeen Search for New Physics Contamination in the Top Quark Samples at D0 Barfuss Searches for Leptoquark production in p p-bar collisions at the D0

experiment Johnson Search for Neutral Long-lived Particles Decaying to b-bbar at D0 Xie Search for Charged Massive Long-Lived Particles Using Data from D0 Culbertson Rare and exotic processes at CDF Gold Searches for new massive vector bosons with CDF Kraus Model Independent Search for New Physics in Leptonic Final States at D0 Gershtein Search for Hidden Valleys with Photons at D0 Ruiz-JimenoRecent results on Bs→μμ and other FCNC decays from the CDF experiment Mackin Search for the Lightest Scalar Top Quark at D0

ConclusionsConclusions


Tevatron, 6/5/09 29

CDF and DØ have a wide and rich program of SUSY searches: Continuously on-going updates of existing results using more

sophisticated techniques and more data Many more results expected for Summer’09 Covering “standard” and unusual scenarios, as well as the

“unconsidered” ones. No evidence of new physics yet, but.. expect to collect and

analyze up to 10 fb-1 of data in the next years Very promising projections GMSB: 10 fb-1

Bs

Stay tuned for more results from the Tevatron!

Back-upBack-up

Model independent searchesModel independent searches


Tevatron, 6/5/09 31

Search for significant deviation from the SM CDF: Use both Vista (model-independent) and Sleuth

(quasi model-independent) to search for new phenomena in 2 fb-1

DØ: Similar Vista/Sleuth approach looking at lepton-based final states in 1 fb-1 : New

!

Out of 180 distributions, 4 significant deviations: + 2 jets + MET (9.3) + + 1 jet + MET (6.6) + MET (4.4) + (4.1)

Difficult modeling: none of these excesses are“sign” for new Physics (Trigger modeling,

Photon mis-identification rate modeling, MC simulation)

PRD 79, 011101 (2009)

Global searches resultsGlobal searches results


Tevatron, 6/5/09 32

DØ Sleuth Results (1 fb-1)Final state P

ℓ+ℓ′- + MET 2.9 E-6ℓ + MET 0.00082ℓ+ℓ′- 0.0031ℓ+τ- + MET 0.006ℓ+ τ+ 0.0066

5 most discrepant final states: P = probability that SM background for an individual final state would have a fluctuation at any cut that would be more significant than what is seen in data

No indication of physics beyond the Standard Model.

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Experimental Searches for SUSY at the Tevatron

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