Search for Supersymmetry Karri Folan DiPetrillo, on behalf Karri - - PowerPoint PPT Presentation
Search for Supersymmetry Karri Folan DiPetrillo, on behalf Karri Folan DiPetrillo, on behalf of the ATLAS Collabora7on of the ATLAS Collabora7on in events with a displaced Moriond Electroweak Moriond Electroweak vertex and a muon 20 March
Karri Folan DiPetrillo, on behalf
Moriond Electroweak 20 March 2019
Karri Folan DiPetrillo, on behalf
Moriond Electroweak 20 March 2019
Karri Folan DiPetrillo — Moriond EW 2019
small 𝜇’ couplings result in a long-lived lightest SUSY particle, undergoes semi-leptonic decay
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23k
23k
Karri Folan DiPetrillo — Moriond EW 2019
Muon Spectrometer only or Missing transverse momentum (ETmiss) trigger
for displaced tracks and secondary vertices
at least one displaced muon and at least one displaced vertex (DV) *muon need not be associated to DV
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Conf Note: ATL-COM-PHYS-2019-006 dataset = 136 X-1 √s=13 TeV pp-collisions collected in 2016-2018
Karri Folan DiPetrillo — Moriond EW 2019
Transverse impact parameter requirement, |d0|>2 mm
ETmiss trigger selection: pT > 25 GeV, |eta|<2.5 Muon trigger selection: pT > 62 GeV, |eta|<1.05
Dedicated vetoes to reject muons from backgrounds
cosmics, heavy flavor decays and algorithm fakes also used to form control regions for background estimation
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µ µ
hadronic jet combinations of random hits
Karri Folan DiPetrillo — Moriond EW 2019
Rxy < 300 mm and |Z|<300 mm ensures displaced tracks can be reconstructed by strip detector
Rxy > 4 mm
to reject hadronic interactions
mass > 20 GeV and at least 3 tracks rejects random track crossings
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PhysRevD.97.052012
Karri Folan DiPetrillo — Moriond EW 2019
1 10
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10 [GeV]
DV
m 2 4 6 8 Events
Data Heavy Flavor Fakes Cosmics )=(1.7 TeV, 0.01 ns)
t ~
τ ,
t ~
(m )=(1.7 TeV, 0.1 ns)
t ~
τ ,
t ~
(m )=(1.7 TeV, 1 ns)
t ~
τ ,
t ~
(m
ATLAS Preliminary
=13 TeV, 136 fb s
Trigger Selection
miss T
E Full Muon Selection Preselected DVs 3 Tracks ≥ Highest mass DV w/
1 10
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10 [GeV]
DV
m 5 10 15 20 Events
Data Heavy Flavor Fakes Cosmics )=(1.0 TeV, 0.01 ns)
t ~
τ ,
t ~
(m )=(1.0 TeV, 0.1 ns)
t ~
τ ,
t ~
(m )=(1.0 TeV, 1 ns)
t ~
τ ,
t ~
(m
ATLAS Preliminary
=13 TeV, 136 fb s
Muon Trigger Selection Full Muon Selection Preselected DVs 3 Tracks ≥ Highest mass DV w/
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ETmiss trigger 0.43 ± 0.16 (stat.) ± 0.16 (syst.) Muon trigger 1.88 ± 0.20 (stat.) ± 0.28 (syst.) 1
Karri Folan DiPetrillo — Moriond EW 2019
But much more phase space to explore, especially in long-lived scenarios!
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˜ t ˜ t p p λ0
23k
µ q λ0
23k
µ q
Exclusion limit for t➝µ+jet ~ arXiv:1810.12602
ATLAS DV+muon
˜ t → qμ
Hand drawn
Karri Folan DiPetrillo — Moriond EW 2019
𝜇’ijk - most constraints on light flavors from CKM measurements, B-physics results, and neutrino less double beta decay 𝜇’23k > 0.45 excluded from Z partial width - LEP
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˜ l
λ λ′ λ′′
˜ q q ˜ q ¯ q ¯ l l ¯ l ¯ q
If we write down SUSY in most generic form we get the following lepton & baryon number violating couplings
Karri Folan DiPetrillo — Moriond EW 2019
agnostic to inner detector activity limited to |𝜃(µ)|<1.05 due to high rates in endcap compare to |𝜃(µ)|<2.4 for standard triggers
high pT muons deposit small fraction of their energy in calorimeter ➝ signal events fire the ETmiss trigger!
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Run 1 Analysis: PhysRevD.97.052012 improves overall signal acceptance·efficiency by over 40% for benchmark model, with negligible increase in backgrounds
Karri Folan DiPetrillo
standard ATLAS tracking requires |d0| < 10 mm large radius tracking is an additional pass of tracking with loosened impact parameter and hit requirements
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IBL B-Layer Layer 1 Layer 2
ATL-PHYS-PUB-2017-014
SCT Layer 1 Layer 2 Layer 1 B-Layer IBL
Pixel Standard Track Large Radius Tracks
SCT Layer 2
rprod
forms vertices using tracks with pT > 1 GeV and |d0| > 2 mm
Karri Folan DiPetrillo — Moriond EW 2019
1 2 3 4 5 6 7 8 9 10
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Initial Filter Trigger
miss T
E > 180 GeV
miss T
E 1 Preselected muon ≥ Fake-muon veto Heavy-flavor veto Cosmic-muon veto 1 Preselected DV ≥ 3 ≥
DV Tracks
n > 20 GeV
DV
m
2 −
10
1 −
10 1 Signal Efficiency
= 13 TeV, 136 fb s Data, )=0.01 ns t ~ ( τ )=1.4 TeV, t ~ m( )=0.1 ns t ~ ( τ )=1.4 TeV, t ~ m( )=1 ns t ~ ( τ )=1.4 TeV, t ~ m(
ATLAS Preliminary
Trigger Selection
miss T
E
1 2 3 4 5 6 7 8 9 10 1 −
10 1 10
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Initial Filter Muon Trigger < 180 GeV
miss T
E 1 Preselected muon ≥ Fake-muon veto Heavy-flavor veto Cosmic-muon veto 1 Preselected DV ≥ 3 ≥
DV Tracks
n > 20 GeV
DV
m
3 −
10
2 −
10
1 −
10 1 Signal Efficiency
= 13 TeV, 136 fb s Data, )=0.01 ns t ~ ( τ )=1.4 TeV, t ~ m( )=0.1 ns t ~ ( τ )=1.4 TeV, t ~ m( )=1 ns t ~ ( τ )=1.4 TeV, t ~ m(
ATLAS Preliminary
Muon Trigger Selection
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Karri Folan DiPetrillo — Moriond EW 2019
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Transfer factors for muon backgrounds
fi = N(events passing veto i) N(events failing veto i)
Karri Folan DiPetrillo — Moriond EW 2019
1 10
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10
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10 Events
ATLAS Preliminary
=13 TeV, 136 fb s
Trigger Selection
miss T
E Full Muon Selection
Data Heavy Flavor Fakes Cosmics )=(1.7 TeV, 0.01 ns)
t ~
τ ,
t ~
(m )=(1.7 TeV, 0.1 ns)
t ~
τ ,
t ~
(m
0 DVs
VR two-track VR low-mass SR
0.5 1 1.5 2 Data/BG 1 10
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10 Events
ATLAS Preliminary
=13 TeV, 136 fb s
Muon Trigger Selection Full Muon Selection
Data Heavy Flavor Fakes Cosmics )=(1.0 TeV, 0.01 ns)
t ~
τ ,
t ~
(m )=(1.0 TeV, 0.1 ns)
t ~
τ ,
t ~
(m
0 DVs
VR two-track VR low-mass SR
0.5 1 1.5 2 Data/BG
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Karri Folan DiPetrillo — Moriond EW 2019
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measure transfer factors in events with DVs in material and as a function of muon impact parameter
Source of uncertainty Relative impact on ✏sel for signal events [%] Total 18 − 20 Tracking and vertex reconstruction 15 Displaced muon efficiency 10 − 12 Prompt muon efficiency (0.01 − 0.7) ⊕ (0.9 − 4.0) Radiation modeling in MC simulation 3 Pileup modeling 0.37 − 2.2 Hadronic energy scale and resolution (affecting Emiss
T
) 2.1 Integrated luminosity of dataset 1.7 Emiss
T
trigger efficiency < 0.2
Karri Folan DiPetrillo — Moriond EW 2019
2 4 6 8 10 12
DV Tracks
n
1 −
10 1 10
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Data Heavy Flavor Fakes Cosmics )=(1.7 TeV, 0.01 ns)
t ~
τ ,
t ~
(m )=(1.7 TeV, 0.1 ns)
t ~
τ ,
t ~
(m )=(1.7 TeV, 1 ns)
t ~
τ ,
t ~
(m
ATLAS Preliminary
=13 TeV, 136 fb s
Trigger Selection
miss T
E Full Muon Selection Preselected DVs
2 4 6 8 10 12
DV Tracks
n
1 −
10 1 10
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5
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Data Heavy Flavor Fakes Cosmics )=(1.0 TeV, 0.01 ns)
t ~
τ ,
t ~
(m )=(1.0 TeV, 0.1 ns)
t ~
τ ,
t ~
(m )=(1.0 TeV, 1 ns)
t ~
τ ,
t ~
(m
ATLAS Preliminary
=13 TeV, 136 fb s
Muon Trigger Selection Full Muon Selection Preselected DVs
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Karri Folan DiPetrillo — Moriond EW 2019
1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2
) [TeV] t ~ m(
4 −
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3 −
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2 −
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1 −
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Upper limit on cross section [pb]
) [NNLO+NNLL] t ~ t ~ → (pp σ
ATLAS Preliminary
= 13 TeV, L = 136 fb s All limits at 95% CL j µ → t ~
)
exp
σ 1 ±
) = 1.00 ns t ~ ( τ ) = 0.10 ns t ~ ( τ ) = 0.01 ns t ~ ( τ
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˜ t ˜ t p p λ0
23k
µ q λ0
23k
µ q
Karri Folan DiPetrillo — Moriond EW 2019
Karri Folan DiPetrillo — Moriond EW 2019