1 Direct Photon + Jet Events at the Compact Muon Solenoid with  s = 14 TeV Michael Anderson University of Wisconsin Preliminary Exam.

Slides:



Advertisements
Similar presentations
Bruce Kennedy, RAL PPD Particle Physics 2 Bruce Kennedy RAL PPD.
Advertisements

Guoming CHEN The Capability of CMS Detector Chen Guoming IHEP, CAS , Beijing.
1 Analysis of Prompt Diphoton Production at the Large Hadron Collider. Andy Yen Mentor: Harvey Newman Co-Mentors: Marat Gataullin, Vladimir Litvine California.
Jet and Jet Shapes in CMS
J. Leonard, U. Wisconsin 1 Commissioning the Trigger of the CMS Experiment at the CERN Large Hadron Collider Jessica L. Leonard Real-Time Conference Lisbon,
Recent Electroweak Results from the Tevatron Weak Interactions and Neutrinos Workshop Delphi, Greece, 6-11 June, 2005 Dhiman Chakraborty Northern Illinois.
1 Hadronic In-Situ Calibration of the ATLAS Detector N. Davidson The University of Melbourne.
8.882 LHC Physics Experimental Methods and Measurements Jet Energy Scale [Lecture 23, May 04, 2009]
1 Search for Excited Leptons with the CMS Detector at the Large Hadron Collider. Andy Yen, Yong Yang, Marat Gataullin, Vladimir Litvine California Institute.
17th Sep JapanTau04 - International workshop on Tau Lepton Physics1 Discovery Potential of the SM Higgs at the LHC Junichi Tanaka ICEPP, University.
Real Time 2010Monika Wielers (RAL)1 ATLAS e/  /  /jet/E T miss High Level Trigger Algorithms Performance with first LHC collisions Monika Wielers (RAL)
1 The CMS Heavy Ion Program Michael Murray Kansas.
The CMS Muon Detector Thomas Hebbeker Aachen July 2001 Searching for New Physics with High Energy Muons.
The Physics Potential of the PHENIX VTX and FVTX Detectors Eric J. Mannel WWND 13-Apr-2012.
Jake Anderson, on behalf of CMS Fermilab Semi-leptonic VW production at CMS.
LHC’s Second Run Hyunseok Lee 1. 2 ■ Discovery of the Higgs particle.
Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla DØ at Run IIa as the new B-Physics/charmonium player Heriberto Castilla Cinvestav-IPN.
Sung-Won Lee 1 Study of Jets Production Association with a Z boson in pp Collision at 7 and 8 TeV with the CMS Detector Kittikul Kovitanggoon Ph. D. Thesis.
Tau Jet Identification in Charged Higgs Search Monoranjan Guchait TIFR, Mumbai India-CMS collaboration meeting th March,2009 University of Delhi.
July CMS experiment at LHC Geoff Hall Imperial College London Geoff Hall.
Heavy charged gauge boson, W’, search at Hadron Colliders YuChul Yang (Kyungpook National University) (PPP9, NCU, Taiwan, June 04, 2011) June04, 2011,
W properties AT CDF J. E. Garcia INFN Pisa. Outline Corfu Summer Institute Corfu Summer Institute September 10 th 2 1.CDF detector 2.W cross section measurements.
1 Perspectives for quarkonium production in CMS Carlos Lourenço, on behalf of CMSQWG 2008, Nara, Japan, December 2008.
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 A Preliminary Model Independent Study of the Reaction pp  qqWW  qq ℓ qq at CMS  Gianluca CERMINARA (SUMMER STUDENT)  MUON group.
Jessica Leonard, U. Wisconsin, February 15, 2007 Preliminary Exam - 1 Vector Boson Fusion Produced Higgs Decays to  Jessica Leonard University of Wisconsin.
Jet Energy Scale at CMS Anwar A Bhatti June 8, 2006 XII International Conference on Calorimetry Chicago IL, USA.
Napoli Doct. School 9 JULY 07 1 DRELL-YAN /Z/Z q q e,e, e+, +e+, +
Olivier RavatLes Houches/June 3rd Higgs associated production at LHC : Thecase Olivier Ravat, Morgan Lethuillier IPN Lyon Les Houches 2003 : Physics.
Search for a Z′ boson in the dimuon channel in p-p collisions at √s = 7TeV with CMS experiment at the Large Hadron Collider Search for a Z′ boson in the.
Il Trigger di Alto Livello di CMS N. Amapane – CERN Workshop su Monte Carlo, la Fisica e le simulazioni a LHC Frascati, 25 Ottobre 2006.
C. K. MackayEPS 2003 Electroweak Physics and the Top Quark Mass at the LHC Kate Mackay University of Bristol On behalf of the Atlas & CMS Collaborations.
Calibration of the CMS Electromagnetic Calorimeter with first LHC data
Multiple Parton Interaction Studies at DØ Multiple Parton Interaction Studies at DØ Don Lincoln Fermilab on behalf of the DØ Collaboration Don Lincoln.
P ARTICLE D ETECTORS Mojtaba Mohammadi IPM-CMPP- February
25 sep Reconstruction and Identification of Hadronic Decays of Taus using the CMS Detector Michele Pioppi – CERN On behalf.
1 Direct Photon Studies in the ATLAS Detector Ivan Hollins 11/04/06 The University of Birmingham.
FIMCMS, 26 May, 2008 S. Lehti HIP Charged Higgs Project Preparative Analysis for Background Measurements with Data R.Kinnunen, M. Kortelainen, S. Lehti,
Prospects in ALICE for  mesons Daniel Tapia Takaki (Birmingham, UK) for the ALICE Collaboration International Conference on STRANGENESS IN QUARK MATTER.
Jet Physics at CDF Sally Seidel University of New Mexico APS’99 24 March 1999.
SUSY08 Seoul 17 June 081 Daniel Teyssier RWTH Aachen University Searches for non-standard SUSY signatures in CMS on behalf of the CMS collaboration.
Jessica Leonard, U. Wisconsin, December 19, 2006 Preliminary Exam - 1 H->  Jessica Leonard University of Wisconsin - Madison Preliminary Examination.
Overview of the High-Level Trigger Electron and Photon Selection for the ATLAS Experiment at the LHC Ricardo Gonçalo, Royal Holloway University of London.
First CMS Results with LHC Beam
Alternatives: Beyond SUSY Searches in CMS Dimitri Bourilkov University of Florida For the CMS Collaboration SUSY06, June 2006, Irvine, CA, USA.
24/08/2009 LOMONOSOV09, MSU, Moscow 1 Study of jet transverse structure with CMS experiment at 10 TeV Natalia Ilina (ITEP, Moscow) for the CMS collaboration.
Abstract Several models of elementary particle physics beyond the Standard Model, predict the existence of neutral particles that can decay in jets of.
Jet Studies at CDF Anwar Ahmad Bhatti The Rockefeller University CDF Collaboration DIS03 St. Petersburg Russia April 24,2003 Inclusive Jet Cross Section.
From the Standard Model to Discoveries - Physics with the CMS Experiment at the Dawn of the LHC Era Dimitri Bourilkov University of Florida CMS Collaboration.
Susan Burke DØ/University of Arizona DPF 2006 Measurement of the top pair production cross section at DØ using dilepton and lepton + track events Susan.
April 7, 2008 DIS UCL1 Tevatron results Heidi Schellman for the D0 and CDF Collaborations.
1 Experimental Particle Physics PHYS6011 Fergus Wilson, RAL 1.Introduction & Accelerators 2.Particle Interactions and Detectors (2) 3.Collider Experiments.
Régis Lefèvre (LPC Clermont-Ferrand - France)ATLAS Physics Workshop - Lund - September 2001 In situ jet energy calibration General considerations The different.
July 27, 2002CMS Heavy Ions Bolek Wyslouch1 Heavy Ion Physics with the CMS Experiment at the Large Hadron Collider Bolek Wyslouch MIT for the CMS Collaboration.
Search for a Standard Model Higgs Boson in the Diphoton Final State at the CDF Detector Karen Bland [ ] Department of Physics,
V. Pozdnyakov Direct photon and photon-jet measurement capability of the ATLAS experiment at the LHC Valery Pozdnyakov (JINR, Dubna) on behalf of the HI.
Searches for Resonances in dilepton final states Searches for Resonances in dilepton final states PANIC th -14 th November 2008, Eilat, ISRAEL A.
 reconstruction and identification in CMS A.Nikitenko, Imperial College. LHC Days in Split 1.
Study of Z  e + e - + Jets with CMS at the LHC Christos Lazaridis University of Wisconsin-Madison Preliminary Examination.
XLIX International Winter Meeting on Nuclear Physics January 2011 Bormio, Italy G. Cattani, on behalf of the ATLAS Collaboration Measurement of.
Direct Photon + Jet Events at CMS with Ös = 14 TeV
Study of Gamma+Jets production
The Compact Muon Solenoid Detector
Kevin Burkett Harvard University June 12, 2001
QCD at LHC with ATLAS Arthur M. Moraes University of Sheffield, UK
Ze+e- + Jets with CMS at the LHC
by M. Della Negra, P. Jenni, and T. S. Virdee
Experimental Particle Physics PHYS6011 Putting it all together Lecture 4 6th May 2009 Fergus Wilson, RAL.
Experimental Particle Physics PHYS6011 Putting it all together Lecture 4 28th April 2008 Fergus Wilson. RAL.
Susan Burke, University of Arizona
Presentation transcript:

1 Direct Photon + Jet Events at the Compact Muon Solenoid with  s = 14 TeV Michael Anderson University of Wisconsin Preliminary Exam

2 Outline  Standard Model   + jet Events  Large Hadron Collider  Compact Muon Solenoid Detector  Detector/Physics Simulation  Reconstructed Jets and Photons  Conclusions & Plans

3 Standard Model  12 elementary matter particles  4 force-carrying particles  1 so far undetected particle: Higgs Quarks (Fermions) Leptons (Fermions) Force Carriers (Bosons) Higgs Quarks only exist in colorless composites!

4 Direct Photons Compton-like Annihilation  Emerge directly from hard scattering  Why look for direct photons? –Energy & position can be measured accurately –Provide good probe of hard-scattering process –Provides direct measure of pdf for gluons  Direct  ’s have high cross-section,  ~ 1 nb for Et(  > 20 GeV  Useful in new physics searches: –Heavy/Composite quarks b’ -> b +  –Supersymmetry Non-direct  ’s example: final state radiation

5 Jets  Quarks exist in colorless composites –Thus fragment to into hadrons  Detector needs to be calibrated for jets –Want to accurately measure 4- momentum of scattered parton  Jet energy losses can be divided into categories: –response of the calorimeter to different particles, –non-linearity response of the calorimeter to the particle energies, –un-instrumented regions of the detector, –multiple interactions and underlying event

6 Photon + Jet  Good for Calibration! –High resolution on prompt  energy ~1% –Jet &  balance in   Can use data to make jet energy corrections –Photon energy calibrated from  0 decays   +jet calibration used by D0 for better than 3% accuracy for jets with 20 GeV < E t < 500 GeV  pp B. Abbot et al. “Determination of the Absolute Jet Energy Scale in the D0 Calorimeter.” Nucl Instr and Meth. A424 (1999)

7 Large Hadron Collider  14 TeV proton-proton collider  Circumference of 27 km  Luminosity up to cm -2 s -1  8T Magnets

8 Proton interactions at LHC Luminosity L = particle flux/time Interaction rate Cross section  = “effective” area of interacting cm -2 s -1

9 Compact Muon Solenoid Solenoid (4T)Muon chambers Silicon Strip & Pixel Tracker Electromagnetic Calorimeter Hadronic Calorimeter Brass/Scintillator Forward calorimeter 6 m diameter

10 Current CMS Surface Underground

11 Particle Detection in CMS  Photons: –Deposit of of Energy in ECAL –No nearby track  Jets –Energy deposit in ECAL & HCAL –With tracks  Detailed reconstruction on later slide

12 Silicon Tracker  Measures pt & path of charged particles within |  | < 2.5  Strip Tracker –200 m 2 coverage –10  m precision measurements –11M electronic channels  Inner Pixel tracking system –66M channels  Used for finding isolated photons and rejecting jets

13   =-ln(tan(  /2) Electromagnetic Calorimeter  Measures energy & position of electrons and photons within |  | < 3  PbWO 4 crystals, very dense (8.3 g/cm 3 ) –23 cm long (26 radiation lengths) –61K in the barrel, 22 x 22 mm 2 –15K in the endcaps, 28 x 28 mm 2  Ultimate precision of energy resolution: 0.5%

14 50 GeV electrons After calibration ECAL Crystal Calibration 9 GeV beam uncalibrated Raw  0 mass  9 GeV beam of  0 ’s used to calibrate ECAL crystals  Energy spectra for 50 GeV electron beam centered on different crystals after calibration –Width of 0.67% consistent with statistical expectation

15 Hadron Calorimeter  HCAL Barrel and HCAL Endcap: brass & scintillator –Coverage to  < 3 –  x  =0.087x0.087  Hadron Outer calorimeter (tail catcher) outside solenoid  Hadron Forward: steel & quartz fiber: coverage 3 <  < 5 –Approx 10K channels HBHE Barrel Resolution

16 Trigger  Level 1: Hardware trigger operating at 40MHz beam crossing rate –Brings event rate down to 100 kHz  Level 2: –Reconstruction done using High-Level Trigger (HLT) -- computer farm –Reduces rate from Level-1 value of up to 100 kHz to final value of ~100 Hz –Slower, but determines energies and track momenta to high precision

17 Level-1 TriggerHFHCALECAL RPCCSCDT Pattern Comparator Trigger Regional Calorimeter Trigger 4  e, J, E T, H T, E T miss Calorimeter Trigger Muon Trigger max. 100 kHz L1 Accept Global Trigger Global Muon Trigger Global Calorimeter Trigger Local DT Trigger Local CSC Trigger DT Track Finder CSC Track Finder 40 MHz pipeline, latency < 3.2  s  Every event is ~1MB each  Identifies potential photons, jets…  Hardware implemented  Reduces rate from 40 MHz -> 100 kHz  Processes each event in 3  s

18 Level-2 e/  Trigger Pixels Tracker Strips ETET   Create “super-clusters” from clusters of energy deposits using Level-1 ECAL information –Must be in area specified by Level-1 trigger –Must have E T greater than some threshold  Match super-clusters to hits in pixel detector –Photons don’t create a hit –Electrons do!  Combine with full tracking information –Track seeded with pixel hit –Final cuts made to isolate photons

19 Outline  Standard Model   + jet Events  Large Hadron Collider  Compact Muon Solenoid Detector  Detector/Physics Simulation  Reconstructed Jets and Photons  Conclusions & Plans

20 Computing PIC Barcelona FZK Karlsruhe CNAF Bologna IN2P3 Lyon T1 T0 FNAL Chicago T1 CMS data sizes and computing needs require a worldwide approach to Physics analysis. FNAL is US CMS national computing center. T2 UW Madison Tier 0 at CERN Record raw data & reconstruction Distribute to T1’s Tier 1 centers Store data from T0’s Make available to T2’s Tier 2 centers Data Analysis Local Data Distribution Wisconsin is a T2 site RAL Oxford

21 Simulation Workflow   +jets simulated with Alpgen v2.1 –Fixed order matrix element simulated event generator –Generates multi-parton and boson + multi-parton processes in hadronic collisions  Jet simulation with Pythia v6.409 –Generates event hadronization, parton shower, and Initial/Final State Radiation, underlying event  Detector simulated using GEANT4 –Toolkit for the simulation of the passage of particles through matter  Reconstruction with CMS software –Same software will be used on real data! ALPGEN Hard scattering PYTHIA Hadronization GEANT4 Detector simulation CMSSW Reconstruction of event

22 Photon Reconstruction  Photons are built from ECAL SuperClusters  All SuperClusters are candidate Photons  “Photon object” contains: –energy in 5x5 crystals –Ratio of energy in 3x3 crystal to SuperCluster energy (R9) –ratio of the energy in center crystal to 3x3 crystals (R19) –presence or not of a matched pixel seed R9 R19 Number of Events / bin

23 Fake Photons  Jet can fake photon –Leading neutral mesons in jet (like  0 ->  and  - >  ) can make narrow deposit of electromagnetic energy –Charged mesons and electrons rejected by tracking system –Shower is often wider for meson decay

24 Reducing Fake Photons  Strategies to minimize fake  background –Reconstruct multiple  energy deposits - see if are decay products of a neutral meson –Select narrow energy deposits –Reject  ->e+e- conversions (multiple  ’s from meson decay more likely to have conversions) –Isolation: require no high energy particles near it

25 Event Selection Start with events corresponding to ∫L  100 pb -1 where  gen  not in ECAL  gap, and Et(  ) > 15 GeV CutReason Events After cut Start480k Photon  < Select barrel photons (well measured)  R Nearest Track > 0.1 (track pt > 10 GeV) Isolation (reject fake photons) Photon R9 > 0.9Narrow Energy Deposit (Shower shape & rejects conversions)

26 Photon ,   Relatively flat in  and   Crack in ECAL  :  Photons near this  harder to find/reconstruct   Generated Reconstructed # Events / bin Keep |  |<1.479

27 Et gen – Et rec Et gen Longer tail on positive side GeV Photon Et  Et of the generated & reconstructed photon match well  Difference in Et ~< 10%  Used default vertex (0,0,0) Generated Reconstructed # Events / bin Keep 15 GeV < Et

28 Photon Shower-Shape  R9 = –Photon shower is narrow  Photons that convert to e + e - pair in Tracker have lower R9  ~73% of all photons in  +jet have R9 > 0.94 –R9 used to select well measured photons E (3x3 crystals) E (SuperCluster) RR # Events / bin Keep 0.94 < R9

29 Nearest Track to Photon RR Nearest Track  R Nearest Track p t GeV # Events / bin Most in overflow Keep 0.1 <  R  Want isolated photons  Nearest Track where –Track pt > 10 GeV –Will lower to 1.5 GeV in future   R =  (  ) 2 + (  ) 2

30 Photon Energy Resolution  Select clean  ’s for calibration  (Et gen –Et rec )/ Et gen  After cuts, fewer events in positive tail  ~24% loss in # of events after R9 cut Before cuts After cuts # Events / bin

31 Event Selection Start with events corresponding to ∫L  100 pb -1 where  gen  not in ECAL  gap, and Et(  ) > 15 GeV CutReason Events After cut Start480k Photon  < Select barrel photons (well measured) 330k (67%)‏  R Nearest Track > 0.1 (track pt > 10 GeV) Isolation (reject fake photons) 310k (65%)‏ Photon R9 > 0.9Narrow Energy Deposit (Shower shape & rejects conversions) 240k (49%)‏

32 Jet Reconstruction  Cone algorithms: –Find seed crystals (starting positions for cone) –Move cone around until E T in cone is maximized –Determine the merging of overlapping cones  Example: –Iterative Cone Seed Et > 1 GeV  R = 0.5 or 0.7 Good for new physics searches and photon+Jet balancing  R =  (  ) 2 + (  ) 2

33 Jet ,   Jet alg: Iterative Cone –R = 0.5 –(Will try out others)  Highest-p t Jet with –p t > 10 GeV –0.8  < |  jet -   | < 1.2   ~93% of events have reconstructed jet that meet this criteria Generated Reconstructed # Events / bin

34 # Events / bin Jet Calibration  Et of reconsructed photon matches well with generated jet pt  But reconstructed jet pt lower by ~ 22 GeV –Even the MC must be calibrated  Well-reconstructed  ’s can be used to calibrate jets! GeV (pt genJet – pt recJet ) pt genJet Generated  Et Generated Jet pt Reconstructed Jet pt # Events / bin (Et gen  – Et rec  ) Et gen  Calibration will shift mean

35 Conclusion & Plans  Photon + Jet events have high cross section –  ~ 1 nb (about 500,000 events in 100 pb -1 )  Calibration of Jet energies is possible and effective using direct photons –Does not depend on monte-carlo jet simulations  Future plans –Probe hard scattering processes –Measure gluon pdf –Tune MC generators  Search for new physics 

36 Extras

37 Calibration Procedure  True jet-parton calibration variable  Can be approximated by  These would be determined in bins of p t,g

38 Supersymmetry  Suggests new symmetry of nature –Every known Standard Model (SM) particle has a SUSY pair particle –SM fermions have SUSY boson partner –SM bosons have SUSY fermion partner  No SUSY particles discovered yet –SUSY particles have higher mass –Thus a broken symmetry!  Predicts massive, stable, weakly interacting particles  One signal for Gauge-Mediated SUSY involves: –decay of next-to-lightest SUSY particle to photon + lightest SUSY particle pp ~~ G ~ G ~  

39 Prev.  + Jet Studies  Konoplianikov, V. et. al. “Jet Calibration using g+Jet Events in the CMS Detector.” CMS NOTE 2006/042  D0 Collaboration, Abbot et al., “Determination of the absolute jet enrgy scale in the D0 Calorimeters.” Nuclear Instruments & Methods A 424 (1999)  D0 Collaboration, B. Abbott et al., "High-pT jets in pbar p collisions at √s=630 and 1800 GeV." Phys.Rev. D64 (2001)  D0 Collaboration, B. Abbott et al., "Isolated Photon Cross Section in ppbar Collisions at √s = 1.8 TeV." Phys.Rev.Lett. 84 (2000)2786.  CDF Collaboration, F. Abe et al., "Properties of photon plus two-jet events in pbar p collisions at sqrt[s]=1.8 TeV." Phys.Rev. D57 (1998)67.  ISR-AFS Collaboration, T. Akesson et al., "Direct-photon plus away- side jet production in pbar p collisions at √s = 63 GeV and a determination of the gluon distribution." Zeit.Phys. C34 (1987)293.

40 3 Generations  Measured cross-section for e+e- > Z/  > q q as function of center of mass energy.  Width of the peak gives a precise measurement of the rate at which Z decays, which in turn specifies the number of neutrino types (number of generations of matter).

41 Photon + Jet  Number of events with direct photons for three regions of  and ∫L = 10 fb -1 ∫L = 10 fb -1

42 Muon System  3 technologies, all self-triggering –drift-tubes(DT), cathode strip chambers(CSC), resistive plate chambers (RPC)  m 2 of active detection planes –100  m position precision in DT and CSC  About 1M electronic channels DTCSCRPC

43 Muons Through Matter  Stopping power (= −dE/dx) for positive muons in copper as a function of βγ = p/Mc over nine orders of magnitude in momentum. Solid curves indicate the total stopping power.