Date post: | 19-Dec-2015 |
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warped extra warped extra dimensions lepton dimensions lepton
signatures in signatures in ATLASATLASO.K. BakerO.K. Baker
Hampton UniversityHampton University(K. McFarlane, V. Vassilakopoulos, T. Shin) (K. McFarlane, V. Vassilakopoulos, T. Shin)
SUSY05SUSY05
gravitons in warped extra gravitons in warped extra dimensionsdimensions
warped extra dimensions warped extra dimensions (Randall-Sundrum model (Randall-Sundrum model PRL PRL 8383, 3370 (1999)), 3370 (1999))
narrow graviton resonances; isolated (?)narrow graviton resonances; isolated (?) decay to SM particlesdecay to SM particles
predictions for . . .predictions for . . . dark energydark energy Higgless mass generationHiggless mass generation dark matterdark matter hierarchy problemhierarchy problem . . .. . .
Planck brane SM (our) brane
fifth dimension
J. Lyyken and L. Randall
parameters, parameters, processes . . .processes . . .
~ kexp(-kr~ kexp(-krcc00) ~TeV ) ~TeV warp factorwarp factor
m = mm = mn+1n+1 - m - mnn = kexp (-kr = kexp (-krcc) ) KK graviton mass gapKK graviton mass gap
q
q
l +
l -
g
g
l +
l -G* G*
q
q
l +
l -
q
q
l +
l -Z0
signal
backgnd
mainly DY
studies presented here . . studies presented here . . ..
study graviton production and decay to study graviton production and decay to electronselectrons
g + g g + g G* G* Z Z00 + Z + Z00
f + f f + f G* G* Z Z00 + Z + Z00
ZZ00 e e-- + e + e+ +
G* G* e e-- + e + e++
Pythia processes 391, 392Pythia processes 391, 392 with tuned underlying eventswith tuned underlying events no pileupno pileup
initial LHC running period (~10 fbinitial LHC running period (~10 fb-1-1))
ATLAS at the LHCATLAS at the LHC
muon systemtoroidalmagnet coil
inner trackingpixel, sct, trt
calori-meters
solenoidmagnet
ATLAS barrel ATLAS barrel TRTTRT
barrel TRT has 105,088 individual detectors; magnetic
field of 2T is parallel to the beam axis.
inner detector
Hampton, Indiana, Duke : mechanical constructionPenn, Yale : electronics
barrel support structure
production facility on campusproduction facility on campus
procedure . . .procedure . . .
generate pythia physics eventsgenerate pythia physics events Pythia 6.2Pythia 6.2
perform GEANT4 simulations on .evgen perform GEANT4 simulations on .evgen files (Rome setup)files (Rome setup)
perform digitization on G4 outputperform digitization on G4 output perform reconstruction on digi outputperform reconstruction on digi output fill ESDsfill ESDs fill AODsfill AODs analysis on AODsanalysis on AODs root trees, histogramsroot trees, histograms
i. e. full analysis chain!!
500 GeV; signal and DY 500 GeV; signal and DY backgroundbackground
signal
DY background
with appropriate statistics for signal and background
DY cut off at 450 GeV
500 GeV; signal and DY 500 GeV; signal and DY backgroundbackground
signal
DY background
with appropriate statistics for signal and background
DY cut off at 450 GeV
G* G* ee 500 GeV; no background ee 500 GeV; no background
330 events simulated 80% reconstruction
500 GeV; signal and DY 500 GeV; signal and DY backgroundbackground
signal
DY
500 GeV; signal and DY 500 GeV; signal and DY backgroundbackground
signal
DY
analysis (700 GeV)analysis (700 GeV)
700 GeV; signal with DY background700 GeV; signal with DY background
with appropriate statistics for signal and
background
G* lab angular distribution; decay G* lab angular distribution; decay products angular distributionproducts angular distribution
electron - one
electron - two
G*
Graviton produced with
momenta along beam
axis
Graviton decay angular distribution
G* G* ZZ ZZ eeee eeee with DY with DY backgroundbackground
DY dielectron background
with appropriate statistics for signal and background
reconstruction
efficiency ~50%
fit to peak
G* G* ZZ ZZ eeee with DY eeee with DY backgroundbackground
DY background
comparison to Tevatron datacomparison to Tevatron data
summarysummary
have completed dielectron studies from have completed dielectron studies from 0.5 TeV up to 1.5 TeV0.5 TeV up to 1.5 TeV
have completed di-boson studies at 1.0 have completed di-boson studies at 1.0 TeVTeV
have included DY and other backgroundshave included DY and other backgrounds compared to Tevatron data; can extend compared to Tevatron data; can extend
mass reach at LHCmass reach at LHC can cover (model) parameter space in a can cover (model) parameter space in a
few years at the LHCfew years at the LHC