new physics searches with z(ll) + x + e t miss final state
DESCRIPTION
New physics searches with Z(ll) + X + E T miss final state. N. Panikashvili and D. Harper University of Michigan, US. General Gauge Mediation (GGM) - motivation. Thanks to Shih/Ruderman ArXiv 0911.4130. effort to formulate gauge mediation in the model independent way - PowerPoint PPT PresentationTRANSCRIPT
New physics searches with Z(ll) + X + ET
miss final state
N. Panikashvili and D. Harper
University of Michigan, US
General Gauge Mediation (GGM) - motivation• effort to formulate gauge mediation in the
model independent way• there is no hierarchy between M of colored
states (squarks, gluinos) and uncolored states (wino, bino, higgsinos, sleptons). The discovery of GGM becomes possibile even with early LHC data in regions of parameter space not probed by any Tevatron searches
• At gauge mediation• LSP is gravitino• NLSP is lightest neutralino, stau ….
• Neutralino is mixture of bino, wino and higgsinos
• If Neutralino is higgsino like, it decays to ~X1 Z + ~G or ~X1 h + ~G and leads to the final states such asZZ+MET, Zh+MET …
• We concentrate on the final state: Z(ll) + jets + MET
Thanks to Shih/Ruderman ArXiv 0911.4130
Tevatron limits:
Z(ll) + jets + METJets + MET
GGM higgsino – like neutralino grid production
• 40 points (50K each one) which cover M(gluino) from 300GeV to 700GeV and M(higgsinos) from 110GeV up to 690GeV
• Parameters of production:
• EF: at least one Zll• Details of the grid:
• Mass spectrum, LO cross sections, filter efficiency, details of production:
https://twiki.cern.ch/twiki/bin/view/AtlasProtected/GGMHiggsinoZGrid
M1 1TeV
M2 1TeV
vary, >0
tan() 1.5
c NLSP 0.1mm
Thanks to Shih/Ruderman ArXiv 0911.4130
GGM grid – different production mechanism
• We investigated the kinematics of the following points we selected 4 points:• M(~g) =300GeV, M(~h)=120GeV• M(~g) =700GeV, M(~h)=120GeV• M(~g) =300GeV, M(~h)=290GeV
• M(~g) =700GeV, M(~h)=690GeV
M(~g)
M(higgsino)
300GeV
120GeV
700GeV
120GeV
300GeV
290GeV
700GeV
690GeV
Electro
weak
f+fbar ~chi1 + ~chi2
<10%
17%
0 <2%f+fbar ~chi+-1 +~chi-+1 18.2%
q+qbar' ~chi1 +~chi+-1 34.4%
q+qbar' ~chi2 +~chi+-1 28.6%
Strongq + qbar -> ~g + ~g 12.9%
<2%14% 33%
g + g -> ~g + ~g 78.6% 86% 65.8%
Dominant production:strong
qqbar~g~g, gg~g~g
Dominant production:electroweak
MC signal cross - section
Fraction of the gluino-gluino pair production
0
0.2
0.4
0.6
0.8
1
1.2
100 200 300 400 500 600 700 800
M(higgsino) GeV
Fra
ctio
n
M(~g) = 300GeV
M(~g) = 400GeV
M(~g) = 500GeV
M(~g) = 600GeV
M(~g) = 700GeV
Fraction of strong vs. weak production for M(~g) = 600 GeV
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
50 100 150 200 250 300 350 400 450 500 550 600 650
M(higgsino) GeV
Fra
ctio
n
gg
total weak prod
neutralino-neutralino
chargino-chargino
neutralino-chargino
NLO cross section
0.01
0.1
1
10
100
0 100 200 300 400 500 600 700 800
M(higgsino) GeV
NL
O c
ross
se
ctio
n *
filt
er
(pb
)
M(~g)=300GeV
M(~g)=400GeV
M(~g)=500GeV
M(~g)=600GeV
M(~g)=700GeV
• Prospino 2
• NLO was calculated using 4 different processes
Event Selection (need an update for 1fb-1)• We are using Standard SUSY di-lepton selection• In addition we require 81GeV < M(ll) < 101GeV, which defines our preselection
• Electrons (1fb-1)
• Muons (689.3pb-1)
Data
Total SM
Z+jets
DrellYan
W+jets
Ttbar
Single top
Dibosons
EE 238389 236541.5 ± 151.5 232709.5±11.7 932.8±37.2 1588.0±37.9
764.1±6.4
78.0±1.0
469.1±3.4
OS
227955 228863.6 ± 147.2 225861.8±139.6
887.9±36.1 900.8±28.5 703.9±6.1 70.35±0.96
438.8±3.3
M>12GeV
226416
228731.8 ± 146.1
225856.9±139.6
782.9±31.4 887.6±28.4
703.90±6.1369.58±0.95
438.8±3.3
Signal leptons
160166 148397.2 ± 115.8 147067.9±112.8
507.4±26.1
21.96±3.08
703.9±6.1 39.6±0.7
438.8±3.3
Z(ee)
136732 129205 ± 154.08 128949 ±155.23
- 4.1 ± 0.9 72.96 ± 2.58 6.4 ± 0.4 172.8±1.6
Data
SM Z+jets
DrellYan
W+jets
Ttbar
Single top
Dibosons
345773
284155.9 191.9 272271.3 153.2
10007.5113.7 303.019.0
914.2 7.0
102.8 1.2
556.23.7
OS
343829
284011.5 191.7
272260.0 153.2
10000.7113.7
224.116.4
883.6 6.9
97.8 1.1
545.23.7
M>12GeV 312151 282916.4 182.9 272248.8153.2
8943.3 98.3
215.016.0
871.8 6.8
96.2 1.1
541.33.7
Signal leptons
299183
275800.6 180 265502.3 151.3
8783.2 97.6
85.4 10.2
820.4 6.6
85.63 523.7 3.6
Z() 240947 225372. 192.2224961.0 193.6
-3.3 0.7
107.9 2.9
12.4 0.5 287.8 1.9
pre-selection results: efficiency of the MC signal
OS EE tight + ISO + mass (17% - 45%) OS MM tight + ISO + mass (6% - 45%)
• Different efficiencies due to different pT spectra
• Different pT cuts: pT = 8GeV/10 GeV, pTleading = 20GeV/25 GeV muons/electrons
Efficien
cy (%)
Efficien
cy (%)
pre-selection results (MET)
• MET depends on the mass of NLSP, the lower mass the lower MET
Large MET region
Signal region 1: MET > 200GeV + inclusive leptons
Efficiency (%)S/√B
• Significance S/√B
Z(ee)+MET>150GeVN(data) = 5N(SM) = 3.1 0.2
pre-selection results (N jets)
• Not optimal variable for the GGM searches with dominant weak production mechanism: M(~g) = 700GeV and M(~h) =120GeV
Leading jet pT
Sub-leading jet pT
Signal region 2: MET > 100GeV, Njets>3
• Improve of the significance in certain regionS/√BEfficiency (%)
Z(ee)+MET>100GeVN jets>3N(data) = 20N(SM) = 13.6 0.5
• N(SM) – is from MC only: ttbar, dibosons, single top, inclusive Z• Errors are statistical only
pre-selection results (HT)
• HT is useful for points with high M(NLSP) and M(~g)
Signal region3: MET>150GeV HT>350GeV
N(data) = 7N(SM) = 4.1 0.2
Effective Mass
Leading lepton pT
N of leptons
Plans
• Background estimation - • Systematic • Enlarge GGM parameter space for the case of Wino
• submitted