Model independent determination of the top quark Yukawa coupling from LHC and ILC data Klaus Desch, Hamburg University Markus Schumacher, Bonn University ECFA LC WS, September 2004, Durham Motivation and Idea LHC rate measurement ILC branching ratio measurement Determination of g t
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Model independent determination of the top quark Yukawa coupling from LHC and ILC data Klaus Desch, Hamburg University Markus Schumacher, Bonn University.
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Model independent determination of the top quark Yukawa coupling
from LHC and ILC dataKlaus Desch, Hamburg University
Markus Schumacher, Bonn University
ECFA LC WS, September 2004, Durham
Motivation and Idea
LHC rate measurement
ILC branching ratio measurement
Determination of gt
Markus Schumacher, Top Quark Yukawa Coupling from LHC and ILC, ECFA LC WS, Durham 2 / 11
Motivation test whether: mf ~ gf
top Yukawa coupling largest:
gt ~ O(1) ( gb ~ O(10-4) )
theoretical prejudice:
maybe surprises for top quark ?
light Higgs: gt from ttH associated production
framework: data from LHC ( L= 30 and 300 fb-1)
data from ILC at ECM = 500 GeV , L=500 fb-1
ILC: small cross section ~ 1.5 to 0.01 fb
for MH= 100 to 145 GeV @ ECM=500GeV
LHC: only rate ppttH, Hxx model independent measurable
gt
Spira et al.
Markus Schumacher, Top Quark Yukawa Coupling from LHC and ILC, ECFA LC WS, Durham 3 / 11
Idea
ILC: measurement of branching ratio BR(Hbb) BR(HWW)
LHC: measurement of rate tth x BR(Hbb)
tth x BR(HWW)
gt x BR(Hxx)
ILC at ??
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Combination of both measurementsmodel independent determination of top quark Yukawa coupling
H
x
x
x
x
Markus Schumacher, Top Quark Yukawa Coupling from LHC and ILC, ECFA LC WS, Durham 4 / 11
LHC rate measurements
Hbb:
tbqq tbl Hbb
~ 110 fb @ MH = 120 GeV
HWW:
a) 2 likesign leptons: tbl+tqq Hl+ qq
b) 3 leptons: t blt blH WW qq l
t blt bqqH WW l l
~ 2 x 18 fb @ MH = 160 GeVBackgrounds considered :