gluon jet

jet analysis
Dec.22/2008 ~
1
visible , without smear, |eta|<1, [0.1,0.1] cells, pp5500GeV
JET PROPERTIES
2
Celljet (the Jet-Finding Method)
1.
divide η-φ space in [0.1, 0.1] cells
2.
calculate transverse energy (eTcell) in each cell
3.
select candidates of jet-seed by eTcell > ”eTseed”
4.
calculate sum of eTcell in the cone which center positioned at jet-seed
(eTsum=ΣeTcell)
5.
requirement : eTsum>”Min-eT”
6.
define the survivors as found jets
Parameters to input are
“eTseed”, “coneRadius”, “Min-eT”
3
Distance btw primary parton and celljet center
assumption:
–
–
•
•
•
dr<1にprimary partonからのjetが入っている
dr<1に他のjetがない
proton
dr<1の中でcelljet.eTが最大のjetをprimary parton起源のjetとした
celljet.coneradius = 1.
distance b/w primary parton & celljet center
proton
parton
found
jet
•
dr
quark
gluon
photon
integral(0~r)
80%
4
Distance btw celljet center and each tracks
•
assumption:
–
–
•
•
•
dr<1にprimary partonからのjetが入っている
dr<1に他のjetがない
dr<1の中でcelljet.eTが最大のjetをprimary parton起源のjetとした
celljet.coneradius = 1.
distance b/w celljet center & each tracks (eT weighted)
quark
gluon
photon
integral(0~r)
80%
5
jet energy balance
• dr(distance btw parton & celljet)
• coneradius
• qq/gg/γγ : jet2 energy/jet1 energy(jet2 energy<jet1 energy)
• qγ/gγ : q/g jet energy/photon jet energy
dr={0.45(quark),0.55(gluon),0.3(photon)},
coneradius=1.0
dr = 0.4, coneRadius=0.25
qq
gg
γγ
qγ
gγ
6
visible/charged/neutral , with smear, |eta|<3, [0.1,0.1] cells, pp5500GeV,
quark jet, dr<{0.45/0.55/0.30}, coneRadius=1.0,
SINGLE JET ANALYSIS
7
charged/neutral
• MineTcharged = MineTvisible*2/3の確認
• energy fraction of each particle seed against with energy
sum of generated particles
MinBias
pTHatMin=200GeV
だいたいOK?
8
influence by smear
•
assumption:
–
•
ALICE-EMC,TPC resolution
setting :
–
–
–
–
dr<0.45(quark)の中でcelljet.eTが最大のjet
dr<0.55(gluon)の中でcelljet.eTが最大のjet
dr<0.30(photon)の中でcelljet.eTが最大のjet
coneRadius=1.0
charged : TPC, Neutral : EMC
particle energy(momentum) is smeared
assume pion mass
EMC
TPC+ITS
P
 0.068 P  0.608[%]
P
E
8.4 2
 2.4 
[%]
E
E
2
9
energy resolution
1.
2.
3.
4.
見つけたcelljet-eT とjet-eT(parton-eT)の相関を作る
直線Fitから補正係数を決定
見つけたcelljet-eTを補正したもの(E’)とjet-eT(parton-eT)(E)から(E’-E)/Eを計算
resolution = (E’-E)/E分布のRMS
eT-eT
correlation
(E’-E)/E Profile
resolution
10
jet energy resolution
•
setting:
–
–
–
–
visible : MineT = 20 GeV
charged : MineT = 20*2/3 GeV
neutral : MineT = 20*1/3 GeV
eTseed = 0.3 * MineT
quark
gluon jet resolution がquarkに比べよい？
=>low-pT粒子でsmearingの桁落ち？
visible resolutionがあまりによい
=>計算違い？
gluon
なんだか怪しいが、計算ミスは見当たらない…
photon
11
parton energy resolution
•
setting:
–
–
–
–
visible : MineT = 20 GeV
charged : MineT = 20*2/3 GeV
neutral : MineT = 20*1/3 GeV
eTseed = 0.3 * MineT
quark
visibleで10~20%程度
ほとんどkinematicsで決まっている
gluon
前pageと同じ計算なので少し自信がない…
photon
12
visible , |eta|<2, [0.1,0.1] cells,
embedded jet : jet center eta < 1. coneradius = 1.0 quark jet
(pp5500GeV からのB-to-B jet)+(HYDJET HD+J event),
JET FINDING METHOD
13
parameter selection(threshold/coneRadius)
•
BKG subtraction
eTcell(sum of eT in cell) < threshold を集めてくる
それらのcellを使いmean-eTを求める(mean-eT)
mean-eTを中心に、v2に応じたBKGを計算(mean-eT’)
全てのeTcellからmean-eT’を引く
pythia-celljetと同じ作業
1.
2.
3.
4.
5.
threshold/coneRadiusはどの程度に設定すべきか？
(Ejet’-Ejet)/Ejetの幅が最小となる値を見つけたい
coneRadius(0.05~0.5)
•
•
jet energy
resolution
(0.1~0.75)
threshold[GeV](0~22)
14
50GeV
100GeV
threshold : 15GeV
coneRadius : centralityの関数
150GeV
0-10%
10-20%
20-30%
30-40%
40-50%
50-60%
16
60-75%
parameter selection(Min-eT/eTseed)
• S/(S+B) ≡ Nreal/Nfound
• efficiency ≡ Nreal/Nembed
Nreal : 見つかったpythiaからのB-to-B jetの数
Nfound : celljetで見つけたB-to-B jetの数
Nembed : 埋め込んだB-to-B jetの数
eTseed/Min-eT(0.1~0.9)
• S/(S+B), efficiencyの値からMin-eT, eTseedの最適化
• {S/(S+B)}*{efficiency}
隣のcellまで許容
pythia B-to-B jet : dphi-PI
1.5sigma
S/(S+B)(0~1)
efficiency(0~1)
{S/(S+B)}*{efficiency}(0~0.9)
Min-eT/pTHat(0.2~1.0)
energy resolution
B-to-B jet の決め方/答え合わせ方法
|dφ-π|<0.284
dr(pythia-jet/found jet) < 0.11
1.-|Efound jet/Epythia jet| < 0.45
17
single quark jet
50~100GeV
{S/(S+B)}*eff
efficiency
S/(S+B)
100~150GeV
150~200GeV
0-10%
10-20%
20-30%
30-40%
40-50%
50-60%
21
60-75%
BtoB quark jet
50~100GeV
{S/(S+B)}*eff
efficiency
S/(S+B)
100~150GeV
150~200GeV
0-10%
10-20%
20-30%
30-40%
40-50%
50-60%
22
60-75%
plan
•
•
•
•
•
gluon jet, photon jet でも同様にconeRadius等の最適化
gamma-jetのS/(S+B),efficiencyの計算
gamma-jetのenergy balanceの計算
(method dependence)
jet quenchingした上で、parton energy lossの計算(再現性能)
27
visible , |eta|<2, [0.1,0.1] cells,
embedded jet : jet center eta < 1. coneradius = 1.0 gluon jet
(pp5500GeV からのB-to-B jet)+(HYDJET HD+J event),
JET FINDING METHOD
28
50GeV
100GeV
threshold : 15GeV
coneRadius : centralityの関数
150GeV
0-10%
10-20%
20-30%
30-40%
40-50%
50-60%
29
60-75%
parameter selection(Min-eT/eTseed)
• S/(S+B) ≡ Nreal/Nfound
• efficiency ≡ Nreal/Nembed
Nreal : 見つかったpythiaからのB-to-B jetの数
Nfound : celljetで見つけたB-to-B jetの数
Nembed : 埋め込んだB-to-B jetの数
eTseed/Min-eT(0.1~0.9)
• S/(S+B), efficiencyの値からMin-eT, eTseedの最適化
• {S/(S+B)}*{efficiency}
隣のcellまで許容
pythia B-to-B jet : dphi-PI
1.5sigma
S/(S+B)(0~1)
efficiency(0~1)
{S/(S+B)}*{efficiency}(0~0.9)
Min-eT/pTHat(0.2~1.0)
B-to-B jet の決め方/答え合わせ方法
|dφ-π|<0.409
dr(pythia-jet/found jet) < 0.11
1.-|Efound jet/Epythia jet| < 0.45
30
single gluon jet
50~100GeV
{S/(S+B)}*eff
efficiency
S/(S+B)
100~150GeV
150~200GeV
0-10%
10-20%
20-30%
30-40%
40-50%
50-60%
31
60-75%
BtoB gluon jet
50~100GeV
{S/(S+B)}*eff
efficiency
S/(S+B)
100~150GeV
150~200GeV
0-10%
10-20%
20-30%
30-40%
40-50%
50-60%
32
60-75%
jet(parton) energy resolution
•
•
•
•
coneRadius : function of centrality
threshold : 15GeV
Min-eT : pTHat * 0.5
eTseed : 0.3 * Min-eT
central
上 : (pythia jet eT) vs (celljet eT(corrected))
下 : (pythia parton eT) vs (celljet eT(corrected))
peripheral
33
jet(parton) energy resolution
jet energy resolution
parton energy resolution
100GeV jet
energy resolution = 25%程度(central)
100GeV parton energy resolution = 25%程度(central)
34
S/(S+B), efficiency, eff*S/(S+B)
• S/(S+B) ≡ Nreal/Nfound
• efficiency ≡ Nreal/Nembed
Nreal : 見つかったpythiaからのB-to-B jetの数
Nfound : celljetで見つけたB-to-B jetの数
Nembed : 埋め込んだB-to-B jetの数
• Min-eT : pTHat * 0.5
• eTseed : 0.3 * Min-eT
S/(S+B)
efficiency
{S/(S+B)}*eff
35
visible , |eta|<2, [0.1,0.1] cells,
embedded jet : jet center eta < 1. coneradius = 1.0 photon
(pp5500GeV からのB-to-B jet)+(HYDJET HD+J event),
JET FINDING METHOD
36
50GeV
100GeV
threshold : 15GeV
coneRadius : 0.1
150GeV
0-10%
10-20%
20-30%
30-40%
40-50%
50-60%
37
60-75%
parameter selection(Min-eT/eTseed)
• S/(S+B) ≡ Nreal/Nfound
• efficiency ≡ Nreal/Nembed
Nreal : 見つかったpythiaからのB-to-B jetの数
Nfound : celljetで見つけたB-to-B jetの数
Nembed : 埋め込んだB-to-B jetの数
eTseed/Min-eT(0.1~0.9)
• S/(S+B), efficiencyの値からMin-eT, eTseedの最適化
• {S/(S+B)}*{efficiency}
隣のcellまで許容
pythia B-to-B jet : dphi-PI
1.5sigma
S/(S+B)(0~1)
efficiency(0~1)
{S/(S+B)}*{efficiency}(0~0.9)
Min-eT/pTHat(0.2~1.0)
B-to-B jet の決め方/答え合わせ方法
|dφ-π|<0.169
dr(pythia-jet/found jet) < 0.11
1.-|Efound jet/Epythia jet| < 0.45
38
single photon
50~100GeV
{S/(S+B)}*eff
efficiency
S/(S+B)
100~150GeV
150~200GeV
0-10%
10-20%
20-30%
30-40%
40-50%
50-60%
39
60-75%
BtoB photon
50~100GeV
{S/(S+B)}*eff
efficiency
S/(S+B)
100~150GeV
150~200GeV
0-10%
10-20%
20-30%
30-40%
40-50%
50-60%
40
60-75%
jet(parton) energy resolution
•
•
•
•
coneRadius : function of centrality
threshold : 15GeV
Min-eT : pTHat * 0.5
eTseed : 0.3 * Min-eT
central
上 : (pythia jet eT) vs (celljet eT(corrected))
下 : (pythia parton eT) vs (celljet eT(corrected))
peripheral
41
jet(parton) energy resolution
jet energy resolution
parton energy resolution
100GeV jet
energy resolution = 25%程度(central)
100GeV parton energy resolution = 25%程度(central)
42
S/(S+B), efficiency, eff*S/(S+B)
• S/(S+B) ≡ Nreal/Nfound
• efficiency ≡ Nreal/Nembed
Nreal : 見つかったpythiaからのB-to-B jetの数
Nfound : celljetで見つけたB-to-B jetの数
Nembed : 埋め込んだB-to-B jetの数
• Min-eT : pTHat * 0.5
• eTseed : 0.3 * Min-eT
S/(S+B)
efficiency
{S/(S+B)}*eff
43
BACK UP SLIDES
44
PYTHIA jet resolution
correlation of jet eT
correlation of parton/jet eT
45
quark
gluon
photon
jet-Not smeared
visible
charged
neutral
46
quark
gluon
photon
jet-smeared
visible
charged
neutral
47
quark
gluon
photon
parton-Not smeared
visible
charged
neutral
48
quark
gluon
photon
parton- smeared
visible
charged
neutral
49
|dφ-π|<0.38
dr(pythia-jet/found jet) < 0.11
1.-|Efound jet/Epythia jet| < 0.45
50
50~100GeV
S/(S+B)
100~150GeV
150~200GeV
0-10%
10-20%
20-30%
30-40%
40-50%
50-60%
51
60-75%
50~100GeV
efficiency
100~150GeV
150~200GeV
0-10%
10-20%
20-30%
30-40%
40-50%
50-60%
52
60-75%
50~100GeV
{S/(S+B)}*eff
100~150GeV
Min-eT = 0.5*pTHat
eTseed = 0.3*Min-eT
実際にはひとつの値しか使えない
150~200GeV
0-10%
10-20%
20-30%
30-40%
40-50%
50-60%
53
60-75%
|dφ-π|<0.3
dr(pythia-jet/found jet) < 0.11
1.-|Efound jet/Epythia jet| < 0.2
54
50~100GeV
S/(S+B)
100~150GeV
150~200GeV
0-10%
10-20%
20-30%
30-40%
40-50%
50-60%
55
60-75%
50~100GeV
efficiency
100~150GeV
150~200GeV
0-10%
10-20%
20-30%
30-40%
40-50%
50-60%
56
60-75%
50~100GeV
{S/(S+B)}*eff
100~150GeV
150~200GeV
0-10%
10-20%
20-30%
30-40%
40-50%
50-60%
57
60-75%
PYTHIA-jetの作り直し
• cellJet configuration : R=0.7
• MineT=20GeV, eTseed=6GeV -> jet candidate
• primary partonからの距離dr<0.3内で最大のeTの
jet(|eta|<1)を選ぶ
• BtoBの決め方
–
–
–
–
２つのprimary partonからのjet(jet1,jet2)
|eTjet1-eTpr1|/(eTjet1+eTpr1)<0.1
|eTjet2-eTpr2|/(eTjet2+eTpr2)<0.1
|veTjet1+veTjet2|/(eTjet1+eTjet2)<0.2
• celljet, primary parton, final particlesの情報を記録
PYTHIA-jetの作り直し
• parameters
–
–
–
–
–
R=0.7 : 充分広く
MineT =20GeV : efficiency ,eTseed=6GeV : MineT*0.3
dr=0.3 : (prparton-celljet)のdphi,detaのRMS~0.2
energy fraction 0.1 : (2~3)*RMS
BtoB variable 0.2 : (2~3)*RMS
quark
gluon
50GeV
100GeV
150GeV
gluon
0.68
0.63
0.58
quark
0.32
0.37
0.42
その前に．．．
• quark/gluon jet separationは難しそう
– quark(gluon) enrich sample
• dijet, gamma-jet
dijet はなんとか識別methodを作った方がよい
gamma-jetはquark-rich
0.73-1.01e-3x
0.27+1.02e-3x
BKGの選択
• mean-eT = <eTcell>|(eTcell<threshold)を求め
る
• mean-eTを中心とした、dphi分布(eTweighted)の幅を持たせてた分布からBKGを
設定
jet energy resolution
• celljet energyによってRを変えるのは変なバイアスがかか
りそうで気持ち悪い
• quark/gluon jetは同じconeRadiusを選ぶ
Min-eT, eTseed
• single/di-jet のS/(S+B) * efficiencyの最大値
• 本物の決め方(1jet)
– PYTHIA-jetとcelljetの距離<0.15^2
– |eTjet-eTcelljet|/eTjet<0.45
• BtoB の決め方
– |dphi-PI|<0.3
– エネルギーの高いjetから選んでいき、一度使ったものは使わない
• 本物の決め方(dijet)
– (1jet)+(1jet)
• 実際には一種類しか使えない
– 50GeV conf.(Min-eT=25GeV, eTseed=7.5GeV)で一度jetを見つけ、その
jet-eTに対しseed-cell-eT > 0.3*jet-eTを要請
yield
• 前頁のdijetのグラフよりそれぞれのcentrality
でのjet-yieldを計算
– Ncollで重み付け
• 前に求めたefficiencyをかけることで
reconstruct可能なjet数が求まる
• acceptanceの効果を加えることでannual
(reconstucted) yieldが求まる

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