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Probing QCD and hadron physics: highlights of experimental results. Chiara Roda Universita` and INFN of Pisa ICHEP2014 - Valencia. Why bother ?. Understanding/testing the QCD theory of SM in a new kinematic range never explored before (LHC) at many different scales (HERA, TeVatron, LHC)

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Probing qcd and hadron physics highlights of experimental results

Probing QCD and hadron physics: highlights of experimental results

Chiara RodaUniversita` and INFN of Pisa

ICHEP2014 - Valencia

C.Roda – Universita` & INFN Pisa


Why bother
Why bother ? results

  • Understanding/testing the QCD theory of SM

  • in a new kinematic range never explored before (LHC)

  • at many different scales (HERA, TeVatron, LHC)

  • in a variety of initial states: ep, ppbar, pp

C.Roda – Universita` & INFN Pisa


Why bother1
Why bother ? results

  • Understanding/testing the QCD theory of SMin a new kinematic range never explored before (LHC)

  • at many different scales (HERA, TeVatron, LHC)

  • in a variety of initial states: ep, pp, pp

LHC collider

pp - √s=7-8 TeV

Operating from 2010

Tevatron collider

pp - √s=1.8 - 1.96 TeV

Operated 1987-2011

HERA collider

e±p - √s=225-320 GeV

Operated 1992-2007

C.Roda – Universita` & INFN Pisa


Why bother2
Why bother ? results

  • Understanding/testing the QCD theory of SMin a new kinematic range never explored before (LHC)

  • at many different scales (HERA, TeVatron, LHC)

  • in a variety of initial states: ep, ppbar, pp

Our level of understanding and modeling of the QCD interactions has direct impact on the potential we have for precision measurements and discovery

Largest syst. For Higgs cross-section is from σ(ggF): 7% scales / 7% PDFs

W/Z+jet is often one of the largest background to top-quark, SUSY, Higgs and exotic searches.

C.Roda – Universita` & INFN Pisa


The ingredients in the predictions
The ingredients in the predictions… results

C.Roda – Universita` & INFN Pisa


The ingredients in the predictions1
The ingredients in the predictions… results

Hard Scattering and parton shower: fixed order NLO partonic calculations (NLOJET++,MCFM,BlackHat), LO+PS (Pythia, Herwig), High multi. LO+PS (Alpgen, Sherpa, Madgraph,…). State of the art: NLO+PS ([email protected]+PS, POWHEG+PS, [email protected])

C.Roda – Universita` & INFN Pisa


The ingredients in the predictions2
The ingredients in the predictions… results

Hard Scattering and parton shower: fixed order NLO partonic calculations (NLOJET++,MCFM,BlackHat), LO+PS (Pythia, Herwig), High multi. LO+PS (Alpgen, Sherpa, Madgraph,…). State of the art: NLO+PS ([email protected]+PS, POWHEG+PS, [email protected])

PDF: CTEQ/CT, NNPDF, MSTW, ABM, HERAPDF…

Differences: data used the fit, αsvalue, treatment of errors, parameterization…

C.Roda – Universita` & INFN Pisa


The ingredients in the predictions3
The ingredients in the predictions… results

Hard Scattering and parton shower: fixed order NLO partonic calculations (NLOJET++,MCFM,BlackHat), LO+PS (Pythia, Herwig), High multi. LO+PS (Alpgen, Sherpa, Madgraph,…). State of the art: NLO+PS ([email protected]+PS, POWHEG+PS, [email protected])

Mostly anti-kT – various cone sizes

PDF: CTEQ/CT, NNPDF, MSTW, ABM, HERAPDF…

Differences: data used the fit, αsvalue, treatment of errors, parameterization…

Measurements are unfolded at particle level to be compared with predictions

C.Roda – Universita` & INFN Pisa


The ingredients in the predictions4
The ingredients in the predictions… results

Hard Scattering and parton shower: fixed order NLO partonic calculations (NLOJET++,MCFM,BlackHat), LO+PS (Pythia, Herwig), High multi. LO+PS (Alpgen, Sherpa, Madgraph,…). State of the art: NLO+PS ([email protected]+PS, POWHEG+PS, [email protected])

A sizeable contribution in understanding our measurements also comes from the quality of modeling of soft hadronic physics… no results in this talk but the measurements are used for the tuning of MC used.

Mostly AntikT – various cone sizes

PDF: CTEQ/CT, NNPDF, MSTW, AMB, HERAPDF…

Differences: data used the fit, αsvalue, treatment of errors, parameterization…

Measurements are unfolded at particle level to be compared with predictions

C.Roda – Universita` & INFN Pisa


Jet cross sections
Jet cross-sections results

Just two examples among the many results …

C.Roda – Universita` & INFN Pisa


Inclusive cross section @ 8 tev

STDM-2013-11 CMS-PAS-FSQ-12-031 CMS-PAS-SMP-12-012 results

Inclusive cross-section @ 8 TeV

8 TeV

16 orders of magnitude

Low pile-up data to extend to the low pT range down to 20 GeV and |y|<4.7

20 Gev – 2 TeV

LHC data allows pQCD tests in a new kinematic regime – extended in pT and y

Covers 16 orders of magnitude / two jet sizes

Reference prediction: NLOJET + NNPDF2.1 but other PDF tested

C.Roda – Universita` & INFN Pisa


More challenge higher multiplicities
More challenge… higher multiplicities results

3-jet

|Y*|=|y1-y2| + |y2-y3| + |y1-y3|

9 orders of magnitude

Mjjj = [0.38,1.2] TeV

Distributions are sensitive both to jet pT and to the angular distributions

Data are compared to many different PDFs, different jet sizes

Data can be used to constrain PDFs (exp and theory uncertainties similar)

C.Roda – Universita` & INFN Pisa


Jet with different sizes what we learn

arXiv:1406;0324 results

Jet with different sizes … what we learn

Inclusive cross-section ratio

R(0.5,0.7) = [dσ(0.5)/dpT]/[dσ(0.7)/dpT]

Variable sensitive to pertubative

radiation, hadronization,

underlying-event

C.Roda – Universita` & INFN Pisa


Jet with different sizes what we learn1

arXiv:1406;0324 results

Jet with different sizes … what we learn

R(0.5,0.7) = [dσ(0.5)/dpT]/[dσ(0.7)/dpT]

C.Roda – Universita` & INFN Pisa


Jet with different sizes what we learn2

arXiv:1406;0324 results

Jet with different sizes … what we learn

R(0.5,0.7) = [dσ(0.5)/dpT]/[dσ(0.7)/dpT]

LONLO

C.Roda – Universita` & INFN Pisa


Jet with different sizes what we learn3

arXiv:1406;0324 results

Jet with different sizes … what we learn

R(0.5,0.7) = [dσ(0.5)/dpT]/[dσ(0.7)/dpT]

LONLO

NLONLO*NP

C.Roda – Universita` & INFN Pisa


Jet with different sizes what we learn4

arXiv:1406;0324 results

Jet with different sizes … what we learn

R(0.5,0.7) = [dσ(0.5)/dpT]/[dσ(0.7)/dpT]

Best description need NLO and parton shower are needed to describe correctly the ratio …

C.Roda – Universita` & INFN Pisa


What we learned from jets
what we learned from jets … results

Inclusive and multiple jet cross-sections have been measured in ATLAS and CMS extending the previously tested kinematic range

Good agreement is found with NLOJET++ prediction

Various PDF tested and most of them show good data description with exception of HERAPDF and in particular ABM11 which show disagreement in some kinematic regions

POWHEG+PYTHIA is found to give the best description of inclusive jet cross-section for different jet sizes

Measurements are used as input to constrain gluon PDFs

C.Roda – Universita` & INFN Pisa


Strong measurement
α strong measurement results

C.Roda – Universita` & INFN Pisa


S measurement

CMS-PAS-SMP-12-028 CMS-PAS-SMP-12-027 resultsarXiv 1406:470

αs measurement

World average (2014)

αs(MZ)= 0.1185 ± 0.0006 (0.5%)

https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSMP

C.Roda – Universita` & INFN Pisa


S measurement1

CMS-PAS-SMP-12-028 CMS-PAS-SMP-12-027 resultsarXiv 1406:470

αs measurement

World average (2014)

αs(MZ)= 0.1185 ± 0.0006 (0.5%)

CMS Most recent: inclusive jet (5%)

https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSMP

C.Roda – Universita` & INFN Pisa


S measurement2

CMS-PAS-SMP-12-028 CMS-PAS-SMP-12-027 resultsarXiv 1406:470

αs measurement

World average (2014)

αs(MZ)= 0.1185 ± 0.0006 (0.5%)

CMS Most recent: inclusive jet (5%)

https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSMP

H1 most recent αs extraction from inclusive and multjet cross-section. Best precision is reached from fit to normalised multijet cross sections:

0.0036 (scale)

exp. unc.0.7%

C.Roda – Universita` & INFN Pisa


S measurement3

CMS-PAS-SMP-12-028 CMS-PAS-SMP-12-027 resultsarXiv 1406:470

αs measurement

World average (2014)

αs(MZ)= 0.1185 ± 0.0006 (0.5%)

CMS Most recent: inclusive jet (5%)

https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSMP

H1 most recent αs extraction from inclusive and multjet cross-section. Best precision is reached from fit to normalised multijet cross sections:

All measurements consistent with world average

Fantastic proof of αs(Q) running up to the TeV region

0.0036 (scale)

exp. unc.0.7%

C.Roda – Universita` & INFN Pisa


S measurement4

CMS-PAS-SMP-12-028 CMS-PAS-SMP-12-027 resultsarXiv 1406:470

αs measurement

World average (2014)

αs(MZ)= 0.1185 ± 0.0006 (0.5%)

CMS Most recent: inclusive jet (5%)

https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSMP

H1 most recent αs extraction from inclusive and multjet cross-section. Best precision is reached from fit to normalised multijet cross sections:

All measurements consistent with world average

Fantastic prove of αs(Q) running up to the TeV region

0.0036 (scale)

exp. unc.0.7%

C.Roda – Universita` & INFN Pisa


Parton distribution functions
Parton Distribution Functions results

C.Roda – Universita` & INFN Pisa


Pdf @ hera zeus h1

H1prelim14-041; ZEUS-prel-14-005 results

PDF @ HERA (ZEUS+H1)

  • HERA – most important data to measure the PDF

  • HERAPDF are based solely on the HERA ep data

e+p - NC

HERAPDF2.0 set recently obtained: use the full HERAI and HERAII dataset

Larger HERAII lumi yields significant improvement in precision at high x, Q2 region

  • Consistent data

  • Large reduction in uncertainties

C.Roda – Universita` & INFN Pisa


Pdf hera2 0 pdf set

H1prelim14-042 ZEUS-prel-14-007 results

PDF – HERA2.0 PDF set

How does HERAPDF1.5 compare to new 2.0 NNLO ?

  • Shapes are similar

  • Gluon and sea at low and high x have smaller uncertainty and they become slightly softer

  • Valence at high x has also smaller uncertainty

C.Roda – Universita` & INFN Pisa


The gluon pdf and input from lhc

CMS-PAS-SMP-12-028 results

The gluon PDF… and input from LHC

PDF fits using only data from experiments with lower momentum transfer than available at the LHC have large uncertainties for the LHC kinematic region.

Data from LHC start to be precise enough to be used for PDF constraint

C.Roda – Universita` & INFN Pisa


The gluon pdf and input from lhc1

CMS-PAS-SMP-12-028 results

The gluon PDF… and input from LHC

PDF fits using only data from experiments with lower momentum transfer than available at the LHC have large uncertainties for the LHC kinematic region.

Gluon PDF constraint from CMS with

7 TeV inclusive jet cross-section

Data from LHC start to be precise enough to be used for PDF constraint

  • CMS fit a harder gluon, with respect to the fit using HERA alone (same results from ATLAS on lower stat. sample)

  • • Fractional uncertainty is smaller at high x, partly due to increased prediction

  • • Measurements are systematic limited at lower jet pT, dominated by the JES uncertainty

C.Roda – Universita` & INFN Pisa


The gluon pdf and input from lhc2

CMS-PAS-SMP-12-028 results

The gluon PDF… and input from LHC

PDF fits using only data from experiments with lower momentum transfer than available at the LHC have large uncertainties for the LHC kinematic region.

Gluon PDF constraint from CMS with 7 TeV inclusive jet cross-section

Very active field more results expected soon…

Data from LHC start to be precise enough to be used for PDF constraint

  • CMS fit a harder gluon, with respect to the fit using HERA alone (same results from ATLAS on lower stat. sample)

  • • Fractional uncertainty is smaller at high x, partly due to increased prediction

  • • Measurements are systematic limited at lower jet pT, dominated by the JES uncertainty

C.Roda – Universita` & INFN Pisa


Inclusive jet hf
Inclusive γ, γ+jet, γ+HF results

C.Roda – Universita` & INFN Pisa


Isolated photon production
Isolated photon production results

  • Photon is used as clean/uncolored probe for underlying parton-parton interaction

  • Test pQCD but also sensitive to non-prompt photons produced in fragmentation processes

  • Provide information on PDFs

Tevatron

LHC – 14 TeV

C.Roda – Universita` & INFN Pisa


Isolated photon production1

Phys.Rev.D 89, 052004 (2014) ATL-PHYS-PUB-2013-018 results

Isolated photon production

7 TeV

No γ from fragmentation

  • New measurement extend the range from 0.1-1TeV ET and 5 orders of magnitude

  • NLO prediction (Jetphox+MSTW or CT10) describe very well the data up to high ET

  • Data demonstrate the need to have fragmentation photon to describe the data

Data is also used to verify the sensitivity to the gluon-PDF and show some tensions with all PDFs expectially with ABM shows a too soft gluon-PDF.

Measurement limited by scale uncertainty, NNLO prediction would help.

C.Roda – Universita` & INFN Pisa


Isolated photon production2

CMS-PAS-SMP-14-005 results

Isolated photon production

8 TeV

Njet ≥1

4 times more statistics  halving of statistical uncertainty

Comparison is at LO … but NLO is coming

  • New measurement extend the range from 0.1-1TeV ET and 5 orders of magnitude

  • NLO prediction (Jetphox+MSTW or CT10) describe very well the data up to high ET

  • Data demonstrate the need to have fragmentation photon to describe the data

Data is also used to verify the sensitivity to the gluon-PDF and show some tensions with all PDFs expectially with ABM shows a too soft gluon-PDF.

Measurement limited by scale uncertainty, NNLO prediction would help.

C.Roda – Universita` & INFN Pisa


Bb cross section d0

Phys.Rev.D 89, 074001 (2014) FERMILAB-PUB-14-135-E results

γ+bb cross-section – D0

  • Higher uncertainty in the prediction than for LF jets

  • Direct access to b-quark PDF

  • Isolation to limit photon from fragmentation

  • Very different process contribution for Tevatron and LHC

  • NLO calculation and kT factorization/NLO approach show good agreement with data.

  • NLO calculation has smaller scale uncertainty

  • PYTHIA fails both shape and rate

  • SHERPA fails at low pT

C.Roda – Universita` & INFN Pisa


W z jets
W/Z+jets results

C.Roda – Universita` & INFN Pisa


A deep look at w jet atlas cms
A deep look at W+jet – ATLAS & CMS results

A detailed comparison on a high statistics sample and in a large kinematics range  precious information to validate/tune the predictions.

Tested variables: 1st , 2nd, 3rd 4th-leading jet pT and η, HT,ST (Sum pT including or not lepton and neutrino), angular separation of jets, invariant mass of lead-subleading jets. Inclusive and exclusive distributions…

Predictions: NLO calculations, resummation calculations, MC generators NLO,LO + PS

C.Roda – Universita` & INFN Pisa


A deep look at w jet atlas cms1

CMS-PAS-SMP-12-023 ATLAS-CONF-2014-035 results

A deep look at W+jet – ATLAS & CMS

Jet multiplicity

C.Roda – Universita` & INFN Pisa


A deep look at w jet atlas cms2

CMS-PAS-SMP-12-023 ATLAS-CONF-2014-035 results

A deep look at W+jet – ATLAS & CMS

Jet multiplicity

Jet multiplicity well reproduced up to ≥7 jets on 5 order of magnitudes !

Best overall description NLO+PS (BlackHat+Sherpa) with some exception for high HT, ST distributions.

C.Roda – Universita` & INFN Pisa


Double differential z jet @ 8 tev

CMS-PAS-SMP-14-009 results

Double differential Z+jet @ 8 TeV

30

First double differential measurement Z+jet

Jet up to |η|<4.7 – 30 < pT<550 GeV

Largest experimental uncertainty JES

Predictions: MadGraph norm.NNLO / Sherpa2 (NLO 1j,2j)

C.Roda – Universita` & INFN Pisa


Double differential z jet @ 8 tev1

CMS-PAS-SMP-14-009 results

Double differential Z+jet @ 8 TeV

First double differential measurement Z+jet

Jet up to |η|<4.7 – 30 < pT<550 GeV

Largest experimental uncertainty JES

Predictions: MadGraph norm.NNLO / Sherpa2 (NLO 1j,2j /LO<=4j)

MadGraph overshoot for pTjet > 100 GeV

Reasonable description from Sherpa2, some regions to investigate

C.Roda – Universita` & INFN Pisa


Boson jets production ratios

CMS-PAS-SMP-14-005 ATLAS-CONF-2014-034 results

Boson+jets production ratios

Ratios allows to reduce experimental systematic uncertainties

Ratio is studied in inclusive and exclusive distributions for Njet≥3

C.Roda – Universita` & INFN Pisa


Boson jets production ratios1

CMS-PAS-SMP-14-005 ATLAS-CONF-2014-034 results

Boson+jets production ratios

Ratios allows to reduce experimental systematic uncertainties

Ratio is studied in inclusive and exclusive distributions of Njet=3

W+jet/Z+jet vs pT jet leading

Njet≥1 - 7 TeV

C.Roda – Universita` & INFN Pisa


Boson jets production ratios2

CMS-PAS-SMP-14-005 ATLAS-CONF-2014-034 results

Boson+jets production ratios

Ratios allows to reduce experimental systematic uncertainties

Ratio is studied in inclusive and exclusive distributions of Njet=3

W+jet/Z+jet vs pT jet leading

Njet≥1 - 7 TeV

Z+jet/γ+jet vs pT boson

Njet≥1 - 8 TeV

C.Roda – Universita` & INFN Pisa


Boson jets production ratios3

CMS-PAS-SMP-14-005 ATLAS-CONF-2014-034 results

Boson+jets production ratios

Ratios allows to reduce experimental systematic uncertainties

Ratio is studied in inclusive and exclusive distributions of Njet=3

W+jet/Z+jet vs pT jet leading

Njet≥1 - 7 TeV

Z+jet/γ+jet vs pT boson

Njet≥1 - 8 TeV

Flattens at high transferred transverse momentum

LO prediction 10% off in norm / good in shape

Detailed test of ratios with respect to NLO/LO predictions

C.Roda – Universita` & INFN Pisa


W z hf
W/Z+HF results

C.Roda – Universita` & INFN Pisa


W charm lhc

JHEP 05 (2014) 068 JHEP 02(2014)013 results

W+charm - LHC

  • Probes the strange content of the proton

  • contribution from d quark about ~10% (Cabibbo suppressed)

  • Different PDFs assume different level of suppression of s-quark w.r. to d-quark sea.

C.Roda – Universita` & INFN Pisa


W c lhc

JHEP05(2014)068 arXiv:1402.6263 arXiv:1312.6283 results

W+c – LHC

ATLAS  no s-sea suppression w.r. to light flavour sea


W c lhc1

JHEP05(2014)068 arXiv:1402.6263 arXiv:1312.6283 results

W+c – LHC

ATLAS  no s-sea suppression w.r. to light flavour sea

CMS  consistent with s-sea suppression


W c lhc2

JHEP05(2014)068 arXiv:1402.6263 arXiv:1312.6283 results

W+c – LHC

ATLAS  no s-sea suppression w.r. to light flavour sea

CMS  consistent with s-sea suppression

Fit s-quark PDF:

HERAPDF including W+c data


W z d production cdf

CDF note 11087 results

W/Z+D* production - CDF

  • Charm identified reconstructing:

    • D* D0 π  Kπ π

  • Measure

  • Separate contributions process comparing same and opposite sign productions and using difference in pT(D∗) distributions: Wc (14±6)%, Wg(cc) (73±8)% , Wg(bb) (13±5)%

PYTHIA6.2+CTEQ5L in good agreement with data

C.Roda – Universita` & INFN Pisa


Z b bb cross sections atlas

STDM-2012-15 results

Z+b/bb cross-sections - ATLAS

5FNS

4FNS and 5FNS

Test of NLO/LO multileg predictions

Test of Number Flavour schemes (4NFS / 5NFS)

C.Roda – Universita` & INFN Pisa


Z b bb cross sections atlas1

STDM-2012-15 results

Z+b/bb cross-sections - ATLAS

5FNS

4FNS and 5FNS

Test of NLO/LO multileg predictions

Test of Number Flavour schemes (4NFS / 5NFS)

PDF

MCFM agrees with data within uncertainties

NLO is still too affected by scale uncertainty to be sensitive to PDFs

Double differential distributions are also compared to different predictions

C.Roda – Universita` & INFN Pisa


Z b bb cross sections atlas2

STDM-2012-15 results

Z+b/bb cross-sections - ATLAS

5FNS

4FNS and 5FNS

Test of NLO/LO multileg predictions

Test of Number Flavour schemes (4NFS / 5NFS)

4FNS

5FNS

MCFM agrees well with data

NLO is still too affected by scale uncertainty to be sensitive to PDFs

Double differential distributions are also compared to different predictions

C.Roda – Universita` & INFN Pisa


And last but not least
and last but not least … results

C.Roda – Universita` & INFN Pisa


Total cross section measurement

ATLAS-CONF-2014-040 results

Total cross-section measurement

  • Basic principle - use Optical theorem to calculate the total cross-section

Measure the differential elastic cross section in the 4-momentum transfer variable t and the extrapolate to t0 to determine the total cross section.

Data are collected with

the ATLAS-ALFA Roman

Pot detector in a

dedicated run.

C.Roda – Universita` & INFN Pisa


Total cross section measurement1

ATLAS-CONF-2014-040 results

Total cross-section measurement

  • Basic principle - use Optical theorem to calculate the total cross-section

Measure the differential elastic cross section in the 4-momentum transfer variable t and the extrapolate to t0 to determine the total cross section.


Conclusions
Conclusions results

  • QCD tested in new kinematic regions, with exclusive and inclusive measurement, often differential or double differential measurements !

  • In many cases the experimental uncertainty is at the level or smaller than theoretical uncertainty

  • The new tools for theoretical predictions have proved to provide a reliable description of data for most of the measurements

  • αsrunning proved up to TeV scale

  • A lot of information to be improve PDF description

C.Roda – Universita` & INFN Pisa


Conclusions1
Conclusions results

  • QCD tested in new kinematic regions, with exclusive and inclusive measurement, often differential or double differential measurements !

  • In many cases the experimental uncertainty is at the level or smaller than theoretical uncertainty

  • The new tools for theoretical predictions have proved to provide a reliable description of data for most of the measurements

  • αsrunning proved up to TeV scale

  • A lot of information to be improve PDF description

pQCD is doing very well up to now …

we are ready for the new challenge at √s = 13 TeV

C.Roda – Universita` & INFN Pisa


Conclusions2
Conclusions results

  • QCD tested in new kinematic regions, with exclusive and inclusive measurement, often differential or double differential measurements !

  • In many cases the experimental uncertainty is at the level or smaller than theoretical uncertainty

  • The new tools for theoretical predictions have proved to provide a reliable description of data for most of the measurements

  • αsrunning proved up to TeV scale

  • A lot of information to be improve PDF description

pQCD is doing very well up to now …

we are ready for the new challenge at √s = 13 TeV

Many thanks to: Sasha Glazov, Maxime Gouzevitch, Ashish Kumar, Christina Mesropian, Alexander Savin, Alessandro Tricoli, Stefan Schmitt, Matthew Wing.

C.Roda – Universita` & INFN Pisa


Back up
Back up results

C.Roda – Universita` & INFN Pisa


Combined fit using lhc jet data

CMS-PAS-SMP-12-028 EPJ (2013) 73 2509 results

Combined fit using LHC jet data

Gluon PDF constraint from CMS with 7 TeV inclusive jet cross-section

ATLAS uses cs ratio (2.7 TeV /7 TeV) to reduce systematic uncertainty

  • Both ATLAS and CMS fit a harder gluon, with respect to the fit using HERA alone

  • • Fractional uncertainty is smaller at high x, partly due to increased prediction

  • • Measurements are systematic limited at lower jet PT, dominated by the Jet Energy Scale uncertainty

C.Roda – Universita` & INFN Pisa


Three jet cross sections
Three jet cross-sections results

C.Roda – Universita` & INFN Pisa


Three jet cross section
Three jet cross-section results

C.Roda – Universita` & INFN Pisa


Three jet cross section1
Three jet cross-section results

C.Roda – Universita` & INFN Pisa


Inclusive jet cross section
Inclusive jet cross-section results

C.Roda – Universita` & INFN Pisa


Inclusive jet cross section1
Inclusive jet cross-section results

C.Roda – Universita` & INFN Pisa



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