Precise"top/quark"mass"" - - PowerPoint PPT Presentation

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Precise"top/quark"mass"" at"hadron"colliders

Sayaka"Kawabata" (SeoulTech)

• !""SK,"Y."Shimizu,"Y."Sumino"and"H."Yokoya,""

""""PLB741"(2015)"232/238

Based"on

!""SK"and"H."Yokoya,"arXiv:1607.00990""

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Outline

1.""IntroducTon"to"mt"eterminaTon 2.""Diphoton"mass"spectrum" 3.""Lepton"energy"distribuTon" 4.""Summary

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1."IntroducTon

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MoTvaTon"to"measure"mt

!""Important"input"to"various"physics"" !""One"of"the"fundamental"parameters"of"the"SM

BuYazzo"et"al."’13 GfiYer"Group"‘14

★""EW"precision"tests"for"SM ★""Beyond"SM ★""SM"vacuum"stability

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0.4"%"precision"! mt"="173.34"±"0.76"GeV Tevatron+LHC"mt"combinaTon

arXiv:1403.4427

Current"status"at"hadron"colliders

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"What"kind"of"mass?

jets Signal"modeling"in"MC Cannot"be"treated"" within"pert."QCD

TheoryMC Experiment

mt"measurement

“Monte/Carlo"mass” "mt

pole,"mt MS

0.4"%"precision"! mt"="173.34"±"0.76"GeV Tevatron+LHC"mt"combinaTon

arXiv:1403.4427

Current"status"at"hadron"colliders

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pole"mass"(CMS)

CMS,"JHEP"08"(2016)"029

""mt

pole"="173.8"±2"GeV

D0,"PLB"703"(2011)"422

"mt

MS""="160.0""""""""GeV

+5.1" −4.5

The"errors"are"sTll"large.

mt

pole,"mt MS"measurements"

0.4"%"precision"! mt"="173.34"±"0.76"GeV Tevatron+LHC"mt"combinaTon

arXiv:1403.4427

Current"status"at"hadron"colliders

"What"kind"of"mass?"mt

pole,"mt MS

“Monte/Carlo"mass”

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Kiyo,"Top"WS@Valencia"2015 Normalized"cross"secTon"for"e+e−"→"Y

!"CLIC"study:""Seidel,"Simon,"Tesar,"Poss,""

" """""""""Eur.Phys.J.C73"(2013)2530

!"ILC"study:""Horiguchi,"Ishikawa,"Suehara,"Fujii,""

""""""""""""""""Sumino,"Kiyo,"Yamamoto,"arXiv:1303.3758

!"N3LO:""BenekeKiyo,"MarquardPenin,"Piclum,""

""""""""Steinhauser,"PRL"115"(2015)192001

mt"measurement"at"future"e+e/"colliders

Threshold"scan"of"Y"producTon

e+ e/ t b

W+ W−

t b

Peak"posiTon"" ""1S"resonance"mass

Kiyo,"Mishima,"Sumino,"JHEP11"(2015)"084

Δmt

MS"30"MeV"in"principle

MS"mass

√s""2mt Y"bound"state

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Aim"of"this"study

"

!Diphoton"mass"spectrum" !Lepton"energy"distribuTon" e+e/"ollider"adron"collider""

QCD"top"mass""

• SK"and"H."Yokoya,"arXiv:1607.00990"

SK,"Y."Shimizu,"Y."Sumino"and"H."Yokoya,"" """"PLB741"(2015)"232/238

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2."Diphoton"mass"spectrum""

• SK"and"H."Yokoya,"arXiv:1607.00990"

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Diphoton"mass"spectrum

+

q q q q

But"large"gluon"PDF !"H"→"γγ"" !"New"resonance"search

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But"large"gluon"PDF

t t

mγγ"2"mt Bound/state"" effects

Diphoton"mass"spectrum

!"H"→"γγ"" !"New"resonance"search

+

q q q q

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Bound/state"effects"(this"work)

Near"Y"threshold"

t

+

"""""""""""""""""""""

Green"fn." in"NRQCD

gg"→"γγ"amplitude

!"One/loop"amplitude"" """for"5"massless/quark"+"top/quark"loop !"Two/loop"amplitude"for"massless/quark"loop

Dicus,"Willenbrock,"PRD37"(1988)"1801 Campbell,"Ellis,"Li,"Williams,"arXiv:1603.02663 Bern,"De"Freitas,"Dixon,"JHEP0109"(2001)"037

Schrodinger"eq.

"… = + + + + +

=

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Light"quarks

+ + + +

t t t t

Diphoton"mass"spectrum"near"threshold

LHC13TeV,"gg"→"γγ ""PDF"and"αS"scale""20% TheoreTcal"uncertainTes e+e−"→"Y"

!"PosiTons"of"dip"and"bump

""Green"fn."scale

!"Overall"normalizaTon "sub/GeV"level 10"%

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mt"measurement"at"LHC"and"FCC

LHC"13TeV FCC"100TeV

SimulaTon Fi{ng"fn":""(gg"predicTon)"+""analyTc"smooth"fn. !"qq"→"γγ" !"gg"→"γγ""generated"according"to"our"calculaTon !FragmentaTon"contribuTons Diphox"(LO)

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172.6 172.8 173.0 173.2 173.4

20 40 60 80

mt GeV

170 172 174 176

10 20 30 40 50 60

mt GeV

EsTmate"of"staTsTcal"error

SensiTvity

FCC"√s"="100TeV" 1"ab/1,"10"ab/1 LHC"√s"="13TeV"" 3"ab/1 !"At"FCC,"systemaTc"uncertainTes"should"dominate. Photon"energy"scale,"isolaTon"cuts,"…

Δmt""2"GeV"for"3"ab/1 Δmt"="0.2"GeV"for"1"ab/1"

!"Higher/order"QCD"correcTons"for"pp"→"γγ"X"would"be"important.

Δmt"="0.06"GeV"for"10"ab/1

NLO"qq,"LO"and"NLO"qg,""NLO"gg

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3."Lepton"energy"distribuTon""

• SK,"Y."Shimizu,"Y."Sumino"and"H."Yokoya,""

""""PLB741"(2015)"232/238

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jets Signal"modeling"in"MC Cannot"be"treated"" within"pert."QCD

Weight"funcTon"method

SK,"Y.Shimizu,"Y.Sumino,"H.Yokoya,"PLB"710,"658"(2012) SK,"Y.Shimizu,"Y.Sumino,"H.Yokoya,"JHEP"08,"129"(2013)

!""Only"lepton"energy"distribuTon"is"needed" ! "Independent"of"top/quark"velocity"distribuTon

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heoreTcally"well/defined"mt jets Signal"modeling"in"MC Cannot"be"treated"" within"pert."QCD Free"from"ambiguity"n"jets""

Weight"funcTon"method

SK,"Y.Shimizu,"Y.Sumino,"H.Yokoya,"PLB"710,"658"(2012) SK,"Y.Shimizu,"Y.Sumino,"H.Yokoya,"JHEP"08,"129"(2013)

!""Only"lepton"energy"distribuTon"is"needed" ! "Independent"of"top/quark"velocity"distribuTon

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160 170 180 190

1.0 0.5 0.0 0.5 1.0

m GeV I

I

m"(GeV)

mt

true

(m)

"("m"="mt

true")"="0

3."Obtain"mt

true""from

Method

2."Using"lepton"energy"dist."from"experiment"""""""""""","" """""perform"its"weighted"integraTon" 1."Compute"a"weight"funcTon"

Lepton"energy"dist."in"the"rest"frame"of"top"quark"(with"mass"m)"

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X"is"unpolarized

For"a"two/body"decay":""X""""""""l"+"Y""

ConstrucTon"of"weight"funcTon

Lepton"energy"distribuTon

1.0 0.5 0.0 0.5 1.0

3 2 1 1 2 3

Ρ

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

0.0 0.1 0.2 0.3 0.4 0.5 0.6

E

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0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

0.0 0.1 0.2 0.3 0.4 0.5 0.6

E

Lepton"energy"distribuTon

X"is"unpolarized

For"a"two/body"decay":""X""""""""l"+"Y""

ConstrucTon"of"weight"funcTon

1.0 0.5 0.0 0.5 1.0

3 2 1 1 2 3

Ρ

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50 100 150 200 250 300

50000 100000 150000 200000 250000

El GeV 160 165 170 175 180 185

20 20 40 60 80

m GeV

106 I

Before"lepton"cuts"

"(×10)

A~er"lepton"cuts

"(m)

t t b b

ν

l +

j j

SimulaTon"analysis

Event"selecTon"cuts"and"background"deform"lepton"distribuTon. LHC"√s"="14"TeV

!

Y"events,"Lepton+jets"channel

!

Parton"level"lepton"distribuTon"

SK,"Y."Shimizu,"Y."Sumino"and"H."Yokoya,"PLB741"(2015)"232/238

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Signal"stat."error 0.4 μF"scale +1.5//1.4 PDF 0.6 Jet"energy"scale +0.2//0.0 BG"stat."error 0.4

UncertainTes"[GeV]"(LO"analysis)

At"100"Ç/1,"Lepton+jets"channel

SensiTvity"of"mt"determinaTon

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NLO

LO LO

t t

b b

Signal"stat."error 0.4 μF"scale +1.5//1.4 PDF 0.6 Jet"energy"scale +0.2//0.0 BG"stat."error 0.4

UncertainTes"[GeV]"(LO"analysis)

Can"be"improved"by"including"NLO" At"100"Ç/1,"Lepton+jets"channel

SensiTvity"of"mt"determinaTon

We"aim"for" Δmt

pole"<"1"GeV"

Scale"uncertainty"in"NLO"top"decay

+0.3//0.2"GeV

LO

NLO NLO

t t

b b

preliminary

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4."Summary

!"We"proposed"two"methods"for"precise"mt"measurement" """at"hadron"colliders." !Precise"determinaTon"of"a"theoreTcally"well/defined"mt"" """"is"demanded. Δmt

pole"<"1GeV"is"probable"at"LHC

!Diphoton"mass"spectrum" !Lepton"energy"distribuTon" Δstat"mt"="0.06"GeV"for"10"ab/1"at"FCC