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SupersymmetryWithTwoSameSignLeptons

Document and Abstract


o ATL-PHYS-PUB-2009-085, ATL-PHYS-INT-2009-065
o A search for R-parity conserving supersymmetry using the ATLAS detector is described. The final state under study includes two same-charge leptons, two jets, and missing transverse energy. A data-driven method to estimate the number of Standard Model background events is proposed, and its discovery potential is assessed assuming an integrated luminosity of 200 pb−1 and a center of mass energy of 10 TeV.

Approved Plots and Tables

[definition of SB and SR using 2D box :]

2-D distribution between pT of second leading jet and missing transverse energy for the ttbar process. The small box that refers to lower values of these two variables is called the Side-Band (SB) and the bigger box called the Signal-likeregion (SR).

Fig2_SB_SR_def.png

[definition of Region A and Region B :]

2-D distribution between transverse mass MT and pT of the second leading lepton. The small box that refers to lower values is called Region B and the higher values of these variables are called Region A.

Fig2_RegA_RegB_def.png

[Effective mass distribution and estimated SM background :]

Effective mass distribution for same-sign dileptons in the inclusive two-jet and missing-energy final state. The events are for 200 ipb integrated luminosity at 10 TeV CM energy. SU4 SUSY signal events are considered for this figure.

SU4_effectiveMassPlot.png

[m0 and m1/2 discovery reach :]

Discovery reach in the mSUGRA m0 and m1/2 plane with the tanB=10, A0=0 and mu>0 configuration. Curves are shown for different luminosity scenario. The hatched regions at smaller m0 values are excluded by the requirement that neutralino be the LSP. The hatched regions at larger m0 values correspond to cases where no mSUGRA solution is found by ISAJET. Significance curves include statistical and systematic errors to the estimated background events. The curves in the plots correspond to a CM energy of 10 TeV.

m0_m12_discovery_reach.png

[squark and gluino mass discovery reach :]

Discovery reach in the squark and gluino masses. Curves are shown for different luminosity scenario. The hatched regions at smaller m0 values are excluded by the requirement that neutralino be the LSP. The hatched regions at larger m0 values correspond to cases where no mSUGRA solution is found by ISAJET. Significance curves include statistical and systematic errors to the estimated background events. The curves in the plots correspond to a CM energy of 10 TeV.

squark_gluino_discovery_reach.png

[signal and backround composition in signal and control regions :]

The expected number of events in 200 ipb for different SM and signal processes. ttbar is the dominant SM process in this analysis. SU4 signals have a very high production cross-section and consequently a sizable number of events survives in the signal region. Only the processes where at least one MC event survived the cuts are shown. The uncertainties on the expected number of events shown in the table arise only from finite Monte Carlo statistics.

table2_bg_composition.png

[result of the background estimation method :]

The expected and the estimated number of SM events in the signal region ASR. The fourth column shows the estimated number of SM events as a result of the extrapolation method. A comparison is made with the expected number of SM events in the signal region for both the no-susy scenario and the susy scenario. All the numbers are shown for 200 ipb of integrated luminosity with a 10 TeV CM energy. Errors in the second and third columns are statistical errors from MC. In the fourth column, the error is from the uncertainty due to finite statistics in the control regions in 200 ipb of data. The expected number of SM background events for different scenarios is always same and it is given in the third column of the first row. This should be compared with the estimated number of SM events given in the fourth column.

table3_result_of_bg_estimation.png


Major updates:
-- TapasSarangi - 2009-08-27

Responsible: TapasSarangi
Last reviewed by: Never reviewed

Topic attachments
I Attachment History Action Size Date Who Comment
PNGpng Fig2_RegA_RegB_def.png r1 manage 45.2 K 2009-08-27 - 16:35 TapasSarangi  
PNGpng Fig2_SB_SR_def.png r1 manage 42.0 K 2009-08-27 - 16:29 TapasSarangi  
PNGpng SU4_effectiveMassPlot.png r1 manage 38.2 K 2009-08-27 - 16:40 TapasSarangi  
PNGpng m0_m12_discovery_reach.png r1 manage 71.2 K 2009-08-27 - 16:48 TapasSarangi  
PNGpng squark_gluino_discovery_reach.png r1 manage 59.3 K 2009-08-27 - 16:51 TapasSarangi  
PNGpng table2_bg_composition.png r1 manage 41.6 K 2009-08-27 - 16:55 TapasSarangi  
PNGpng table3_result_of_bg_estimation.png r1 manage 36.3 K 2009-08-27 - 17:00 TapasSarangi  
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Topic revision: r6 - 2010-12-06 - PatrickJussel
 
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