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