Experimental Searches for Experimental Searches for SUSY at the Tevatron SUSY at the Tevatron Monica D’Onofrio IFAE-Barcelona On behalf of the CDF and DØ collaborations On behalf of the CDF and DØ collaborations SUSY’09 SUSY’09 , , Boston, USA, June 5-10, 2009 Boston, USA, June 5-10, 2009
Experimental Searches for SUSY at the Tevatron. Monica D’Onofrio IFAE-Barcelona On behalf of the CDF and DØ collaborations SUSY’09 , Boston, USA, June 5-10, 2009. _. The Tevatron. Fermilab. p. p. Highest-energy accelerator currently operational performing very well!. CDF. DØ. - PowerPoint PPT Presentation
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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
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
Monica D'Onofrio, IFAEExperimental Searches for SUSY at the
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’’
Monica D'Onofrio, IFAEExperimental Searches for SUSY at the
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
Monica D'Onofrio, IFAEExperimental Searches for SUSY at the
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
m0 = 60 GeV, tan 3, A0=0, >0m0 = 60 GeV, tan 3, A0=0, >0
~~ ~~
~
~ ~
0022 ±±
1 1 in trileptons: resultsin trileptons: results
Monica D'OnofrioExperimental Searches for SUSY at the
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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
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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
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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
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~~ ~~
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
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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:
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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!
Stop searches: Stop searches:
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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!
~ ~
Stop searches: Stop searches:
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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
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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
Monica D'OnofrioExperimental Searches for SUSY at the
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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
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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
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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
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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.