jet calibration in cms: experience… lot of questions… and few answers… …a work in...

Jet Calibration in CMS: experience…

lot of questions… and

few answers……a work in progress…

Attilio SantocchiaINFN PerugiaFrascati – 2nd Workshop sui Monte Carlo, la Fisica e le Simulazioni a LHC22.05.2006

FRASCATI 22.05.2006 - MC WorkShop Attilio Santocchia 2

Motivations

• ttH channel very challenging: we have to optimize all the tools we need to use…

• Which is the best Jet Algorithm to use for such a complex multi-jet final state rich with b-jets?

• I used to study the fully hadronic decay 8 jets (4 light + 4 b jets)

• Honestly? It’s a mess! And jets are the most important object I had to understand…


Chosen Algorithm & Data Sample

• 5 Different Iterative Cone Algorithm + 3 KT inclusive

– ICA DeltaR=0.30, 0.35, 0.40, 0.45 and 0.50

– KT r=0.35, 0.40 and 0.45

• COMPHEP+PYTHIA 6.215+CTEQ4L– ttH120 (200K)

– ttjj (1000K) 1.6M events

– ttbb (400K)

• ALPGEN2+PYTHIA 6.325+CTEQ5L– tt1j exclusive (1000K)

– tt2j exclusive (560K)

– tt3j exclusive (68K)

– tt4j inclusive (97K)

1.725M events


• To do physics we need to go back to parton energy

• 2 different aspect to be considered:– Detector Effects PARTICLE level correction

– Physics Model Effects PARTON level correction

• I tried to factorize the 2 effects:

• 2 different set of Calibration functions are calculate

for correction to JetMC Energy and to Parton Energy

• These functions are then applied to the raw jet energy in cascade to recover the initial Parton Energy

Calibration

ET(raw) ET(MCjet) ET(parton)


Raw Jet

• Standard Jets from CMS simul+reco

software

• No Calibration

• Calorimeter Noise Cut are: ET > 0.5

GeV and E > 0.8 GeV

• Raw Jet ET > 5 GeV

• All Jets are considered massless


MC Jets• Built from stable generator particles and ET > 0.5 (1) GeV

• Muons and Neutrinos are included in the calculation

• Muons and Neutrinos are excluded in the calculation

– If you keep all particles Jet is the same (difference in ET below 5%)

but CPU time needed for ICA increases of a factor 2-3

• Jet is kept if ET(jet) > 10 (20) GeV

• We need to b-tag MC jets to build flavored dependant calibration:

– Each particle belonging to a jet is classified as daughter of a b-

flavored unstable particle or not

– Define b-ratio as sum of energy from particles from b divided jet

energy

– If b-ratio > 0.20 then jet is tagged as a MC b-jet


Jet Costituents• After ICA application, I can list all the

particles used to form the Jet (Jet Components)

• Each Particle in the Jet can be associated either to the partons from the hard scattering or nothing

• Most of the time 100% of the particles within a jet comes from the same original parton…

• But sometimes there is a mixing…


Particles String Partonsi part Name Isthep m1 M2 D1 d2 px py pz E m

0 2212 proton 3 -1 -1 -1 -1 0 0 7000 7000 0,941 2212 proton 3 -1 -1 -1 -1 0 0 -7000 7000 0,942 21 g 3 0 -1 -1 -1 0,02 0,04 162,9 162,9 03 2 u 3 1 -1 -1 -1 0,16 -0,54 -3202,62 3202,62 04 21 g 3 2 -1 -1 -1 0,2 14,28 87,85 89,01 05 21 g 3 3 -1 -1 -1 -21,45 -17,27 -933,09 933,5 06 6 t 3 4 5 -1 -1 74,18 -72,67 -305,09 367,41 176,427 -6 t_bar 3 4 5 -1 -1 -128,4 105,45 -368,51 440,11 174,038 25 h0 3 4 5 -1 -1 32,96 -35,76 -171,63 214,99 119,999 24 W+ 3 6 -1 -1 -1 95,14 -77,25 -147,82 208,61 81,53

10 5 b 3 6 -1 -1 -1 -20,96 4,58 -157,27 158,8 4,6211 -1 d_bar 3 9 -1 -1 -1 58,79 -57,55 -145,59 167,22 0,3312 2 u 3 9 -1 -1 -1 36,15 -19,55 -2,11 41,15 0,3313 -24 W- 3 7 -1 -1 -1 -28,16 -9,75 -163,05 184,07 80,0614 -5 b_bar 3 7 -1 -1 -1 -100,24 115,2 -205,47 256,04 4,6215 1 d 3 13 -1 -1 -1 -36 -39,74 -113,75 125,75 0,3316 -2 u_bar 3 13 -1 -1 -1 7,78 30,15 -49,17 58,2 0,3317 5 b 3 8 -1 -1 -1 -21,01 26,09 -12,82 36,16 4,6218 -5 b_bar 3 8 -1 -1 -1 53,97 -61,85 -158,81 178,83 4,62

61 2 u 2 12 -1 240 240 4,27 -6,82 4,24 9,11 0,3362 21 g 2 12 -1 240 240 12,34 -4,73 -5,47 14,3 063 21 g 2 12 -1 240 240 6,71 -2,61 -5,35 8,97 064 21 g 2 12 -1 240 240 8,6 -5,38 -7,82 12,81 065 21 g 2 11 -1 240 240 3,19 -2,93 -3,46 5,54 066 -1 d_bar 2 11 -1 240 240 14,09 -7,52 -8,18 17,95 0,33

240 92 string 2 61 66 241 252 49,21 -29,99 -26,04 68,69 26,8


Jet Classification - ExampleJET= 4 jet= 4 EtJ=33.731 EtaJ=-1.211 PhiJ=-0.899 EJ=61.810 n= 0 Npar=192 Strg=191 Part= 4 EtP= 6.883 EtaP=-1.234 PhiP=-0.864 EP=12.832 dR= 0.042 n= 1 Npar=193 Strg=191 Part= 4 EtP=13.563 EtaP=-1.249 PhiP=-0.921 EP=25.595 dR= 0.044 n= 2 Npar=371 Strg=191 Part= 4 EtP= 1.528 EtaP=-1.243 PhiP=-0.918 EP= 2.873 dR= 0.038 n= 3 Npar=373 Strg=191 Part= 4 EtP= 1.604 EtaP=-0.925 PhiP=-0.825 EP= 2.391 dR= 0.295 n= 4 Npar=375 Strg=191 Part= 4 EtP= 4.728 EtaP=-1.204 PhiP=-0.892 EP= 8.606 dR= 0.009 n= 5 Npar=376 Strg=191 Part= 4 EtP= 1.334 EtaP=-1.417 PhiP=-1.046 EP= 2.916 dR= 0.254 n= 6 Npar=507 Strg=191 Part= 4 EtP= 2.061 EtaP=-1.067 PhiP=-0.838 EP= 3.351 dR= 0.155 n= 7 Npar=508 Strg=191 Part= 4 EtP= 2.061 EtaP=-1.027 PhiP=-0.890 EP= 3.246 dR= 0.184

JET= 5 jet= 5 EtJ=25.726 EtaJ= 1.639 PhiJ= 2.254 ThetaJ= 0.384 EJ=68.962 n= 0 Npar=238 Strg= 91 Part= 0 EtP= 3.739 EtaP= 1.902 PhiP= 2.357 EP=12.810 dR= 0.283 n= 1 Npar=258 Strg=110 Part= 3 EtP= 3.686 EtaP= 1.487 PhiP= 2.340 EP= 8.585 dR= 0.174 n= 2 Npar=261 Strg=110 Part= 3 EtP= 5.652 EtaP= 1.518 PhiP= 2.170 EP=13.564 dR= 0.147 n= 3 Npar=262 Strg=110 Part= 3 EtP= 1.627 EtaP= 1.466 PhiP= 2.034 EP= 3.716 dR= 0.279 n= 4 Npar=422 Strg= 91 Part= 0 EtP= 1.370 EtaP= 1.977 PhiP= 2.286 EP= 5.042 dR= 0.340 n= 5 Npar=438 Strg=110 Part= 3 EtP= 3.864 EtaP= 1.560 PhiP= 2.246 EP= 9.615 dR= 0.079 n= 6 Npar=439 Strg=110 Part= 3 EtP= 4.426 EtaP= 1.622 PhiP= 2.279 EP=11.641 dR= 0.031 n= 7 Npar=440 Strg=110 Part= 3 EtP= 1.457 EtaP= 1.665 PhiP= 2.249 EP= 3.990 dR= 0.027

• First Jet is PURE: all the particles comes from the same string ; the associated parton code is 4 (a W+)

• Second Jet is a mixing of t_bar (code 3) and something else (code 0)

• How can I treat this kind of situation?


Jet Classification – An Event• ttH fully hadronic CompHEP• Iterative Cone Algo (Cone Size 0.4)

• ET(particles isthep=1)>1GeVIndex 0 Jet 3 Et=164.511 Eta=-2.067 Phi=-2.742 RatioE=0.800 Quark Higgs Index 1 Jet 0 Et=147.849 Eta=-2.614 Phi= 0.030 RatioE=1.000 Quark top Index 2 Jet 2 Et=105.950 Eta=-2.131 Phi=-0.131 RatioE=0.742 Quark W+ Index 3 Jet 1 Et=102.842 Eta=-0.176 Phi= 2.456 RatioE=0.981 Quark top_bar Index 4 Jet 4 Et= 33.731 Eta=-1.211 Phi=-0.899 RatioE=1.000 Quark W+ Index 5 Jet 5 Et= 25.726 Eta= 1.639 Phi= 2.254 RatioE=0.741 Quark top_bar Index 6 Jet 7 Et= 11.329 Eta=-1.117 Phi= 1.326 RatioE=1.000 Quark Higgs Index 7 Jet 8 Et= 8.020 Eta=-2.585 Phi=-2.695 RatioE=1.000 Quark Higgs Index 8 Jet 9 Et= 6.469 Eta= 0.227 Phi= 2.937 RatioE=1.000 Quark W- Index 9 Jet 10 Et= 4.530 Eta=-0.108 Phi=-3.023 RatioE=1.000 Quark W- Index 10 Jet 6 Et= 4.008 Eta=-2.951 Phi= 0.251 RatioE=1.000 Quark top Index 11 Jet 12 Et= 3.490 Eta=-1.442 Phi= 0.667 RatioE=1.000 Quark Higgs Index 12 Jet 11 Et= 2.566 Eta= 0.574 Phi=-2.994 RatioE=1.000 Quark W- Index 13 Jet 13 Et= 1.797 Eta=-2.101 Phi= 3.061 RatioE=1.000 Quark Higgs Index 14 Jet 14 Et= 1.566 Eta=-3.743 Phi=-0.466 RatioE=1.000 Quark top Index 15 Jet 15 Et= 1.548 Eta=-2.106 Phi=-2.194 RatioE=1.000 Quark Higgs Index 16 Jet 16 Et= 1.494 Eta=-0.598 Phi= 1.332 RatioE=1.000 Quark Higgs Index 17 Jet 17 Et= 1.325 Eta=-1.567 Phi=-0.483 RatioE=1.000 Quark W+ Index 18 Jet 18 Et= 1.320 Eta= 1.166 Phi= 2.320 RatioE=1.000 Quark top_bar Index 19 Jet 19 Et= 1.297 Eta= 2.246 Phi= 2.674 RatioE=1.000 Quark no partIndex 20 Jet 20 Et= 1.263 Eta=-2.534 Phi=-0.745 RatioE=1.000 Quark top Index 21 Jet 21 Et= 1.003 Eta=-0.934 Phi=-2.936 RatioE=1.000 Quark no part

• In real life, low ET Jets are objects difficult to detect

• Only jets with ET>10(20)GeV will be used in the next slides


How many MC jets?tt1j – All Particles – ET>10GeV

tt1j tt2j tt3j tt4j

IC30 8.32/ 8.27 9.52/ 9.47 10.72/ 10.67 13.94/ 13.88

I C35 8.43/ 8.39 9.59/ 9.54 10.74/ 10.69 13.78/ 13.73

I C40 8.52/ 8.48 9.62/ 9.58 10.70/ 10.66 13.58/ 13.53

I C45 8.59/ 8.55 9.62/ 9.59 10.64/ 10.60 13.33/ 13.29

I C50 8.63/ 8.60 9.61/ 9.57 10.55/ 10.52 13.05/ 13.02

KT r=0.35 8.51/ 8.46 9.70/ 9.65 10.88/ 10.84 14.04/ 13.99

KT r=0.40 8.61/ 8.57 9.75/ 9.71 10.88/ 10.85 13.87/ 13.83

KT r=0.45 8.70/ 8.66 9.78/ 9.75 10.85/ 10.82 13.66/ 13.62

• <Njet> distribution for different jet algo– Black is ICA– Red is KT

• In the table <Njet>: – red is maximum <Njet>– 1st number is AllParticle –

2nd is noMuNu

Iterative Cone• If <Njet> increase when R

increase I get more jets because of ET(jet)>10GeV

• If <Njet> decrease when R increase overlapping

KT

• If <Njet> increase when r increase Again depends on ET(jet)>10GeV

• If <Njet> decrease when r increase ???


Jet Formation Overlapping

tt1j tt2j tt3j tt4j

IC30 99.21% 99.16% 99.15% 99.97%

I C35 99.11% 99.07% 99.03% 98.99%

I C40 99.00% 98.98% 98.94% 98.91%

I C45 98.91% 98.88% 98.87% 98.83%

I C50 98.81% 98.8% 98.79% 98.77%

KT r=0.35 99.09% 99.06% 99.01% 98.99%

KT r=0.40 98.98% 98.95% 98.92% 98.90%

KT r=0.45 98.86% 98.84% 98.82% 98.83%

tt1j – All Particles – ET>10GeV

Black is ICA – Red is KT

Fractio of jets with jetRatio > 0.80

Fractio of jets with jetRatio > 0.90 97.3% ÷ 97.9%


• Look for each particle belonging to the jet…

• Define b-Ratio and c-Ratio– ratioParticle = E(particle)/E(jet)

– If(decayFromBquark) ratioForBjet+=ratioParticle

– elseIf(decayFromCquark) ratioForCjet+=ratioParticle

• A jet is a bJet if:– (ratioForBjet>ratioForCjet) && (ratioForBjet>CutBjetRatio)

• A jet is a cJet if:– (ratioForCjet>ratioForBjet) && (ratioForCjet>CutCjetRatio)

• What are CutBjetRatio And CutBjetRatio?

• See next slides…

bJets and cJets Classification

Jet

Bfrom

E

Eb ratio-

Jet

Cfrom

E

Ec ratio-


b-ratio Distribution

b-ratio>0.2

Jet

Bfrom

E

Eb ratio-b-ratio>0.2

Sample tt2j: ICA 0.300.50 – KT r=0.350.45 ICA 0.40: sample tt1j… tt4j

tt1j

tt1j tt2j tt3j tt4j

2/7=28.6% 2/8=25% 2/9=22.2% <2/10=20%

IC30 22.02% 19.51% 17.51% 14.25%

I C35 22.03% 19.62% 17.69% 14.51%

I C40 22.01% 19.72% 17.85% 14.79%

I C45 21.96% 19.77% 18.00% 15.04%

I C50 21.88% 19.83% 18.11% 15.27%

KT r=0.35 22.07% 19.60% 17.63% 14.39%

KT r=0.40 21.92% 19.56% 17.67% 14.55%

KT r=0.45 21.78% 19.54% 17.73% 14.72%

Percentuale di bJet taggabili!

Sono meno di quelli che mi aspetto… (in percentuale!)

I bJet troppo soffici li perdo…

E il gluon splitting è trascurabile


c-ratio Distribution

c-ratio>0.2

Jet

Cfrom

E

Ec ratio-

c-ratio>0.2

• Same criteria a jet is classified as a cJet when more than

20% of its energy comes from c haddrons (and there are no b

in the decay chain…)

– tt1j ~ 11.2% are cJets




tt1j tt2j tt3j tt4j

bJ ets 22.0% - 1.9 19.7% - 1.9 17.7% - 1.9 14.7% - 2.0

cJ ets 11.2% - 0.9 10.4% - 1.0 9.8% - 1.0 8.8% - 1.2

light J ets 66.8% - 5.7 67.9% - 6.5 72.5% - 7.8 76.5 - 10.5

<Njet> 8.5 9.6 10.7 13.7


Minimum Distance (b and c partons)

tt1j tt2j tt3j tt4j

bJ ets 84.7% 84.2% 83.4% 81.5%

cJ ets 83.7% 83.0% 81.5% 77.7%

Fractio of jets nearer than 0.2 from a b(c) parton in the hard scatteringJet Algo is ICA and R=0.4


b Minimum Distance VS bRatio

• Example for tt2j and ICA cone 0.4

• Here we can evaluate the gluon splitting

• bJets with bRatio>0.5 and minDistB>0.5 are not

coming from a b parton in the hard scattering 6.2%

• bJets with bRatio>0.2 and minDistB>0.8 are not

coming from a b parton in the hard scattering 4.0%


Calibration Raw Jet MC Jet• Build jets from Full Reco (FR)

• Build jets from Generator (MC) particles list

• Match FR-MC jets minimizing RFR-MC; keep jets where

RFR-MC< 0.3

• Fill 50x 200ET histos with ET(FR)/ET(MC) for b-jets and

not-b-jets in the range abs(eta)<5 and ET<600 GeV

• Gaussian Fit if Nent>30

• For each Eta Value, fit the ET Ratio as a function of

ET(raw) using the function

cbEaE

ErecoT

MCT

recoT

1


Calibration MC Jet Parton• Build jets from Generator (MC) particles list

• Match jets-Parton minimizing RMC-Parton; keep jets

where RMC-Parton< 0.15

• Fill 50x 200ET histos with ET(MC)/ET(Parton) for b-

jets and not-b-jets in the range abs(eta)<5 and ET<600 GeV

• Gaussian Fit if Nent>30

• For each Eta Value, fit the ET Ratio as a function of

ET(MC) using the function

cbEaE

EMCT

PartonT

MCT

1


Raw-MC jet Ratio Distribution MC jet-Parton Ratio Distribution

• Example for 1 of the 10000 bins in which the eta-ET plane has

been divided

• Red is b-jets - Black is not-b-jets

• Fit done in 2 steps:– First in the whole histo range [0,2] Get Mean and Sigma

– Second in the range [mean-2.5*sigma,mean+2.5*sigma]

Single ET Ratio Distribution


Ratio vs ET Distribution

• Eta Ring 0.5<<0.6• Red is b-jets - Black is not-b-jets• No needs to distinguish b-jets for MC-Parton• Error Bar are defined as /sqrt(N) where is the width of

the second fit and N is number of Entry (see slide #11)

Raw-MC jet Ratio Distribution MC jet-Parton Ratio Distribution

ET(GeV) ET(GeV)


Fitted Parameter Raw Jet MC Jet

• Fitted parameters as a function of eta• Red is b-jets - Black is not-b-jets

Parameter a Parameter b Parameter c

Here is the tracker Barrel-EndCaps Border!


Fitted Parameter MC Jet Parton (R=0.5)

• Fitted parameters as a function of eta• b-jets and not-b-jets are together• Each parameter fitted with a streight line

Parameter a Parameter b Parameter c


Parton Calibration - Fitted Para – Different Cone – All Particles

● ICA 0.30● ICA 0.35● ICA 0.40● ICA 0.45● ICA 0.50

Light Jets

bJets


Ratio vs ET DistributionInput Particles is NoMuNu

Eta=0.5-0.6ET=51-54GeV


Ratio vs Eta Distribution (ET=45-48 GeV)

Input Particles is NoMuNu and All Particles

• Here AllParticles and NoMuNu show differences (for low eta)• But this is not a homogeneous functions…• Matching 0.15 is not enough? See also the Single

distributions and the left tail…


MCJet to ttH Comparison (cone 0.5)

• 3 different eta bin No major difference above 40 GeV for not-b-jets and 60 GeV for b-jets

• Difference due to different Calibration:– MCJet is only particle level– ttH is particle level and parton level

• Parton level correction important for low ET jets


MC Jet Definition… what I learned…

• Option Jet input list:– All Particles

– NoMuNu

• No major differences the difference in bJets/lightJets is minor (negligible?)

• Particle Calibration keeps the high difference btw bJets/lightJets…– Depends on the fragmentation used…

– bJets charged spectrum different from lightJets

– To recover correctly the jet energy is mandatory to tag the jets and use 2 different corrections for bJets and lightJets

• Parton Calibration could be the same for all experiments (ATLAS/CMS)…– Providing the definition is the same for both od us…

– All Particles keeps simple the definition for parton calibration


Invariant Masses ttH fully Hadronic

• To cross-check the quality of the calibration functions, invariant masses for the W,t and Higgs particles are used

• The 8 most energetic jets in the tracker are paired to the 8 partons in the final state using R.

• All the events where alle the 8 jets are paired with R<0.3 have been selected

• Invariant mass are built using the calibrated jets for each algorithm-calibration


Cono ET(min) Part. ET(min) J et M(w) Sigma(W) M(top) Sigma(top) M(Higgs) Sigma(Higgs) Nevent

0,30 0,00 10 73,5 5,5 162,5 9,7 109,2 7,9 219

0,30 0,00 20 73,7 5,1 162,5 9,6 108,5 7,5 239

0,30 0,25 10 73,4 5,6 162,2 8,7 109,6 7,1 224

0,30 0,25 20 73,5 5,1 162,4 9,4 108,3 7,3 232

0,30 0,50 10 72,6 5,8 161,1 8,8 107,8 7,4 2360,30 0,50 20 73,0 4,9 161,7 9,0 106,6 7,9 219

0,40 0,00 10 75,3 6,1 168,4 10,0 112,8 7,1 240

0,40 0,00 20 76,0 5,6 167,2 10,2 112,4 6,6 227

0,40 0,25 10 75,0 6,7 167,7 10,1 111,4 7,1 246

0,40 0,25 20 75,1 5,5 166,9 9,1 112,4 6,1 221

0,40 0,50 10 73,5 6,5 165,3 9,3 111,1 5,7 269

0,40 0,50 20 74,6 5,2 164,3 10,0 111,4 6,6 213

0,50 0,00 10 77,1 7,1 170,7 11,8 115,4 6,8 190

0,50 0,00 20 78,3 7,0 171,3 12,8 115,5 7,0 195

0,50 0,25 10 76,6 7,1 169,7 12,5 115,1 6,3 207

0,50 0,25 20 77,3 6,7 170,1 12,5 115,0 7,2 194

0,50 0,50 10 75,7 6,9 167,4 12,4 112,3 6,9 2170,50 0,50 20 76,1 6,6 167,4 11,9 112,9 6,9 184

Invariant Masses ttH fully Hadronic from MC Jets

• 1000 events used for this exercise…• No DeltaR matching Look for configuration 3+3+2 and correct

JetRatio associations (see slide #9-#10)• Cone 0.5 is the more ermetic… OK but how many events survive

the request 3+3+2?• Cone 0.4 is better… less ermetic but sigma is better, and Nevents

is a lot better!


Invariant Masses ttH fully Hadronic

• Invariant Masses for (from left to right) W,t and Higgs• Upper row is Standard CMS MC-Jet calibration and DeltaR=0.5• Lower row is ttH-calibration and DeltaR=0.5

Minv(GeV) Minv(GeV) Minv(GeV)

Minv(GeV) Minv(GeV) Minv(GeV)


Invariant Masses full Results

• Resolution is defined as /M• Numer of selected events and Resolution give a hint on the

best algorithm to use

• ICA R=0.4 and inclusive KT seems good choice

CMS ICA 0.30 ICA 0.35 ICA 0.40 ICA 0.45 ICA 0.50 KT incl

MW 81,50 81,58 81,58 81,80 82,12 82,80 82,74

Mt 172,05 172,86 173,05 173,72 174,70 176,09 176,20

MH 105,54 108,85 109,29 109,92 110,72 111,15 112,20

W 13,84 12,98 13,19 13,22 13,46 13,56 12,58

t 22,20 21,06 20,97 21,01 21,30 21,20 20,63

H 19,29 18,83 19,05 19,04 19,12 19,33 18,58

RESW 0,170 0,159 0,162 0,162 0,164 0,164 0,152

RESt 0,129 0,122 0,121 0,121 0,122 0,120 0,117

RESH 0,183 0,173 0,174 0,173 0,173 0,174 0,166

Eff(%) 4,08 5,90 6,39 5,98 5,20 4,28 5,40


• Analysys based on mass for jet pairing

• 8 most energetic jets in ||<2.7

• Centrality Cuts (All and Higgs)

• The mass for 2W and 2tops within 3 sigma from expected values

• Different cut for Btag and ET jets

• Significance S/sqrt(N) and S/N used as benchMark

Analysis from the CMS P-TDR ttH fully Hadronic

2222

2

)()()()(

t

jjt

t

jjt

W

jjW

W

jjWmass m

mm

m

mm

m

mm

m

mm

jet

jetT

E

E

8

8All Centrality

jet

jetT

E

E

2

2Higgs Centrality


Same Analisys Different Parton Calibration

2.4

2.2

2.0

1.8

1.6

1.4

1.2

1.0

121086420

CompHEP ALPGEN No Parton Calibration ICA 0.30 ICA 0.30 ICA 0.30 ICA 0.40 ICA 0.40 ICA 0.40 ICA 0.50 ICA 0.50 ICA 0.50


ConclusionsNon ci sono ancora! ma…

• La parton calibration è necessaria per noi sperimentali

• La definizione di MCjet potrebbe essere uguale per tutti

(ATLAS/CMS)…

• In questo modo si potrebbe chiedere ai teorici/sperimentali di

definire un unico oggetto che può essere usato da noi

sperimentali per la particle calibration…

• E dai teorici per la parton calibration… che è uguale per tutti…

• In ogni caso la particle calibration non può essere unica per tutti

i jets…

• Ma una distinzione tra bJets e lightJets è necessaria…

• Non ho ancora guardato il KT… mea culpa…

jet calibration in cms: experience… lot of questions… and few answers… …a work in...

Documents

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