Presentation is loading. Please wait.

Presentation is loading. Please wait.

Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa Jets & Pile-up …. C.Roda – Universita` & INFN Pisa.

Published byBerenice Cole Modified over 8 years ago

Similar presentations

Presentation on theme: "Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa Jets & Pile-up …. C.Roda – Universita` & INFN Pisa."— Presentation transcript:

1 Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa Jets & Pile-up …. C.Roda – Universita` & INFN Pisa

2 Layout Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa Effects of large pile-up Standard pile-up correction discrimination between jets from pile-up and Hard Scattering Next steps to improver jet response Effects of large pile-up Standard pile-up correction discrimination between jets from pile-up and Hard Scattering Next steps to improver jet response Ref.: A.Schwartzman @ PC: https://indico.cern.ch/getFile.py/access?subContId=2&contribId=1&resId=0&materialId=slides&confId=184536 https://indico.cern.ch/getFile.py/access?subContId=2&contribId=1&resId=0&materialId=slides&confId=184536 J.Backus https://indico.cern.ch/getFile.py/access?contribId=1&resId=1&materialId=slides&confId=185880 L.Bryngemark https://indico.cern.ch/getFile.py/access?contribId=0&resId=0&materialId=slides&confId=161253 Note: Pile-up in 2011 – ATL-COM-PHYS-2012-349 Ref.: A.Schwartzman @ PC: https://indico.cern.ch/getFile.py/access?subContId=2&contribId=1&resId=0&materialId=slides&confId=184536 https://indico.cern.ch/getFile.py/access?subContId=2&contribId=1&resId=0&materialId=slides&confId=184536 J.Backus https://indico.cern.ch/getFile.py/access?contribId=1&resId=1&materialId=slides&confId=185880 L.Bryngemark https://indico.cern.ch/getFile.py/access?contribId=0&resId=0&materialId=slides&confId=161253 Note: Pile-up in 2011 – ATL-COM-PHYS-2012-349

3 Effects from pile-up Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa Effects: o add soft jets from different but pp interactions o add energy and fluctuations to jets Effects: o add soft jets from different but pp interactions o add energy and fluctuations to jets μ = average number of interactions per bunch-crossing N PV = number of primary vertices Pile-up event multiplicity: 2010: μ ~ 0 - 4 2011: μ ~ 3 – 8  5 - 17 2012: μ ~ 40 Signal shaping time (especially in LAr) ~ 8 bunch-crossing  large effect also of pp interaction bunch-crossing close to the one that triggers. μ = average number of interactions per bunch-crossing N PV = number of primary vertices Pile-up event multiplicity: 2010: μ ~ 0 - 4 2011: μ ~ 3 – 8  5 - 17 2012: μ ~ 40 Signal shaping time (especially in LAr) ~ 8 bunch-crossing  large effect also of pp interaction bunch-crossing close to the one that triggers. ΔpT / N PV (MeV)ΔpT / μ (MeV) ΔR = 0.437060 / -310 ΔR = 0.6850210 / -470 2011 estimates

4 What μ=40 means… Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa At pT ~ 20 GeV HS jets are ~ as pile-up jets

5 Again on the pile-up effect Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa No pile-up μ ~ 5 μ ~ 25 Simple assessment from http://www.lpthe.jussieu.fr/~salam/jet-quality/http://www.lpthe.jussieu.fr/~salam/jet-quality/ Pythia, no detector effects. Simple assessment from http://www.lpthe.jussieu.fr/~salam/jet-quality/http://www.lpthe.jussieu.fr/~salam/jet-quality/ Pythia, no detector effects.

6 Offset correction also for 2012 Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa

7 What μ = 40 means … Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa Jet multiplicity on multijet –QCD events from MC using AntiKt06 LC Topoclusters jets Pile-up largely contribute to pT > 20 GeV jets Offset partially diminish the problem… Jet multiplicity on multijet –QCD events from MC using AntiKt06 LC Topoclusters jets Pile-up largely contribute to pT > 20 GeV jets Offset partially diminish the problem…

8 Std correction effect on resolution Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa μ = 0 resolution ~ NoCorrection/3

9 What next ? Distinguishing HS from PU Jets: Jet Vertex Fraction (JVF) Correcting the energy on an event-by- event basis or jet-by-jet basis Distinguishing HS from PU Jets: Jet Vertex Fraction (JVF) Correcting the energy on an event-by- event basis or jet-by-jet basis Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa

10 JVF: Jet Vertex Fraction Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa JVF = Sum pT trks matched to the jets from primary vtx Sum pT trks matched to the jets Std cuts used in analysis to select HS jets: |JVF|>0.75

11 JVF for μ=20 Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa PU HS

12 JVF efficiency and fake rate Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa Studies are ongoing to define a weighted JVF (using for example DeltaR trk) to improve the efficiency in selecting HS jets μ=20 μ=40

13 Event-by-event offset Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa Jet Area + pTDensity (ρ)

14 Event-by-event offset Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa

15 Event-by-event offset Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa

16 Summary Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa Effect of high pile-up: -increase low pT jets, large contribution to jet pT and large pT fluctuation Step0: Average correction developed for 2011 data fne(N PV,μ) is also validated for μ=40. Work on-going Step1: optimize JVF to be able to discriminate HS from PU jets in with large pile-up Step2: use Jet Area and/or track from non-primary vtx to correct the jet pT  better resolution The road is still long ….

17 Back up slides Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa

18 Jet-by-Jet correction Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa Use the Sum of the track pT not belonging to the primary vtx and matched to the jet (SPTO) to correct the energy response. Δp T = pTAfterOffsetCorrection - pTTruth Similar behavior at mu=40 But low pT trend not understood yet… Similar behavior at mu=40 But low pT trend not understood yet…

19 Area correction Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa

20 Sigma noise calo Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa

21 Understanding the pile-up Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa N PV inclusive or μ inclusive No pT dependence for the slope Choose p T =[20,30] GeV and consider offset vs N PV and μ N PV inclusive or μ inclusive No pT dependence for the slope Choose p T =[20,30] GeV and consider offset vs N PV and μ offset = difference between the pT of the jet and the pT of the jet at the mean values of N PV and µ. Slopes gives N PV dependence intercept µ dependence. offset = difference between the pT of the jet and the pT of the jet at the mean values of N PV and µ. Slopes gives N PV dependence intercept µ dependence.

22 Estimating the pile-up systematic Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa Evaluate μ inclusive offset from: γ+jet – p T =[25-45] GeV track-jet - p T =[20-25] GeV MC truth - p T =[20-30] GeV MC is μ weighed Evaluate μ inclusive offset from: γ+jet – p T =[25-45] GeV track-jet - p T =[20-25] GeV MC truth - p T =[20-30] GeV MC is μ weighed Linear Fit to MC truth slope and evaluate the residuals of various methods. Error is evaluated by fitting a linear function to Δoffset (blu line) Linear Fit to MC truth slope and evaluate the residuals of various methods. Error is evaluated by fitting a linear function to Δoffset (blu line) J.Backus Mayes

23 More distant future Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa

Download ppt "Atlas Italia Meeting Roma – 17.4.2012C.Roda – INFN & University of Pisa Jets & Pile-up …. C.Roda – Universita` & INFN Pisa."

Similar presentations

Impact parameter studies with early data from ATLAS

Impact parameter studies with early data from ATLAS
Barbara Sciascia – LNF 1 K  semileptonic BR measurement B. Sciascia 4 may 2006 KpmKSL joint meeting.

Barbara Sciascia – LNF 1 K  semileptonic BR measurement B. Sciascia 4 may 2006 KpmKSL joint meeting.
B Tagging with CMS Fabrizio Palla INFN Pisa B  Workshop Helsinki 29 May – 1 June 2002.

B Tagging with CMS Fabrizio Palla INFN Pisa B  Workshop Helsinki 29 May – 1 June 2002.
Niccolo’ Moggi XII DIS April 15 2004 The “Underlying Event” at CDF Niccolo’ Moggi Universita’ and I.N.F.N, Bologna for the CDF Collaboration April 15,

Niccolo’ Moggi XII DIS April The “Underlying Event” at CDF Niccolo’ Moggi Universita’ and I.N.F.N, Bologna for the CDF Collaboration April 15,
June 6 th, 2011 N. Cartiglia 1 “Measurement of the pp inelastic cross section using pile-up events with the CMS detector” 1 2 4 3 8 5 6 7 How to use pile-up.

June 6 th, 2011 N. Cartiglia 1 “Measurement of the pp inelastic cross section using pile-up events with the CMS detector” How to use pile-up.
Top Turns Ten March 2 nd, 2005. Measurement of the Top Quark Mass The Low Bias Template Method using Lepton + jets events Kevin Black, Meenakshi Narain.

Top Turns Ten March 2 nd, Measurement of the Top Quark Mass The Low Bias Template Method using Lepton + jets events Kevin Black, Meenakshi Narain.
Kevin Black Meenakshi Narain Boston University

Kevin Black Meenakshi Narain Boston University
Sept 30 th 2004Iacopo Vivarelli – INFN Pisa FTK meeting Z  bb measurement in ATLAS Iacopo Vivarelli, Alberto Annovi Scuola Normale Superiore,University.

Sept 30 th 2004Iacopo Vivarelli – INFN Pisa FTK meeting Z  bb measurement in ATLAS Iacopo Vivarelli, Alberto Annovi Scuola Normale Superiore,University.
Introduction to Hadronic Final State Reconstruction in Collider Experiments Introduction to Hadronic Final State Reconstruction in Collider Experiments.

Introduction to Hadronic Final State Reconstruction in Collider Experiments Introduction to Hadronic Final State Reconstruction in Collider Experiments.
1 N. Davidson Calibration with low energy single pions Tau Working Group Meeting 23 rd July 2007.

1 N. Davidson Calibration with low energy single pions Tau Working Group Meeting 23 rd July 2007.
Introduction Week of Jets FNAL, Aug. 24-28, 2009 Aug 23, 2009 Introduction To Jet Reconstruction In ATLAS Peter Loch University of Arizona Tucson, Arizona.

Introduction Week of Jets FNAL, Aug , 2009 Aug 23, 2009 Introduction To Jet Reconstruction In ATLAS Peter Loch University of Arizona Tucson, Arizona.
4/10/12 Contribution in ATLAS Collaboration 1 Talk “Multi-jet balance for high pT jet calibration” presented on ATLAS Hadronic Calibration Workshop 2011(SLAC.

4/10/12 Contribution in ATLAS Collaboration 1 Talk “Multi-jet balance for high pT jet calibration” presented on ATLAS Hadronic Calibration Workshop 2011(SLAC.
Tau Jet Identification in Charged Higgs Search Monoranjan Guchait TIFR, Mumbai India-CMS collaboration meeting 27-28 th March,2009 University of Delhi.

Tau Jet Identification in Charged Higgs Search Monoranjan Guchait TIFR, Mumbai India-CMS collaboration meeting th March,2009 University of Delhi.
Energy Flow and Jet Calibration Mark Hodgkinson Artemis Meeting 27 September 2007 Contains work by R.Duxfield,P.Hodgson, M.Hodgkinson,D.Tovey.

Energy Flow and Jet Calibration Mark Hodgkinson Artemis Meeting 27 September 2007 Contains work by R.Duxfield,P.Hodgson, M.Hodgkinson,D.Tovey.
Jet Studies at CMS and ATLAS 1 Konstantinos Kousouris Fermilab Moriond QCD and High Energy Interactions Wednesday, 18 March 2009 (on behalf of the CMS.

Jet Studies at CMS and ATLAS 1 Konstantinos Kousouris Fermilab Moriond QCD and High Energy Interactions Wednesday, 18 March 2009 (on behalf of the CMS.
1 2vtx tagged diBjets mass cross section measurement Univeristy of Notre Dame Hong Luo Mar 3 th 2005.

1 2vtx tagged diBjets mass cross section measurement Univeristy of Notre Dame Hong Luo Mar 3 th 2005.
August 30, 2006 CAT physics meeting Calibration of b-tagging at Tevatron 1. A Secondary Vertex Tagger 2. Primary and secondary vertex reconstruction 3.

August 30, 2006 CAT physics meeting Calibration of b-tagging at Tevatron 1. A Secondary Vertex Tagger 2. Primary and secondary vertex reconstruction 3.
HERA-LHC, CERN Oct.11 2004 Preliminary study of Z+b in ATLAS /1 A preliminary study of Z+b production in ATLAS The D0 measurement of  (Z+b)/  (Z+jet)

HERA-LHC, CERN Oct Preliminary study of Z+b in ATLAS /1 A preliminary study of Z+b production in ATLAS The D0 measurement of  (Z+b)/  (Z+jet)
Multiple Parton Interaction Studies at DØ Multiple Parton Interaction Studies at DØ Don Lincoln Fermilab on behalf of the DØ Collaboration Don Lincoln.

Multiple Parton Interaction Studies at DØ Multiple Parton Interaction Studies at DØ Don Lincoln Fermilab on behalf of the DØ Collaboration Don Lincoln.
Status of K S   e analysis C. GattiT. Spadaro Selection on data Selection on MC Efficiencies from data, K L   e, K S    ,      , bhabha.

Status of K S   e analysis C. GattiT. Spadaro Selection on data Selection on MC Efficiencies from data, K L   e, K S    ,      , bhabha.

Similar presentations

Ads by Google