A Comparison of Three-jet Events in p Collisions to Predictions from a NLO QCD Calculation Sally Seidel QCD’04 July 2004.

Slides:



Advertisements
Similar presentations
Charged Particle Jet measurements with the ALICE Experiment in pp collisions at the LHC Sidharth Kumar Prasad Wayne State University, USA for the ALICE.
Advertisements

Jet and Jet Shapes in CMS
09/30/'06SPIN2006, T. Horaguchi1 Measurement of the direct photon production in polarized proton-proton collisions at  s= 200GeV with PHENIX CNS, University.
10/03/'06 SPIN2006, T. Horaguchi 1 Measurement of the direct photon production in polarized proton-proton collisions at  s= 200GeV with PHENIX CNS, University.
Dijet Transverse Thrust cross sections at DØ Veronica Sorin University of Buenos Aires.
DØ Run II jet algorithms E. Busato (LPNHE, Paris) TeV4LHC Workshop 12/1/2004 Outline:  Introduction  The Ideal Jet Algorithm  DØ Run II Cone Jet Algorithm.
Jet Physics at the Tevatron Sally Seidel University of New Mexico XXXVII Rencontres de Moriond For the CDF and D0 Collaborations.
Jets Physics at CDF Sally Seidel University of New Mexico Ninth Adriatic Meeting 8 September 2003 for the CDF Collaboration.
Michele Gallinaro, "QCD Results at CDF" - XXXVIII Rencontres de Moriond, March 22-29, QCD Results at CDF Inclusive Jet Cross Section Dijet Mass.
Single-Top Cross Section Measurements at ATLAS Patrick Ryan (Michigan State University) Introduction to Single-Top The measurement.
November 1999Rick Field - Run 2 Workshop1 We are working on this! “Min-Bias” Physics: Jet Evolution & Event Shapes  Study the CDF “min-bias” data with.
ATLAS UK Physics meeting
Measurement of Inclusive Jet cross section Miroslav Kop á l University of Oklahoma on behalf of the D Ø collaboration DIS 2004, Štrbské pleso, Slovakia.
Moriond 2001Jets at the TeVatron1 QCD: Approaching True Precision or, Latest Jet Results from the TeVatron Experimental Details SubJets and Event Quantities.
CDF Joint Physics Group June 27, 2003 Rick FieldPage 1 PYTHIA Tune A versus Run 2 Data  Compare PYTHIA Tune A with Run 2 data on the “underlying event”.
PIC 2001 Michael Strauss The University of Oklahoma Recent Results on Jet Physics and  s XXI Physics in Collision Conference Seoul, Korea June 28, 2001.
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.
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.
Studies of the jet fragmentation in p+p collisions in STAR Elena Bruna Yale University STAR Collaboration meeting, June
16/04/2004 DIS2004 WGD1 Jet cross sections in D * photoproduction at ZEUS Takanori Kohno (University of Oxford) on behalf of the ZEUS Collaboration XII.
Run 2 Monte-Carlo Workshop April 20, 2001 Rick Field - Florida/CDFPage 1 The Underlying Event in Hard Scattering Processes  The underlying event in a.
Fermilab MC Workshop April 30, 2003 Rick Field - Florida/CDFPage 1 The “Underlying Event” in Run 2 at CDF  Study the “underlying event” as defined by.
Multiple Parton Interaction Studies at DØ Multiple Parton Interaction Studies at DØ Don Lincoln Fermilab on behalf of the DØ Collaboration Don Lincoln.
Study of Direct Photon Pair Production in Hadronic Collisions at √s=14 TeV (Preliminary Results) Sushil Singh Chauhan Department of Physics & Astrophysics.
Hadronic Event Shapes at 7 TeV with CMS Detector S,Banerjee, G. Majumdar, MG + ETH, Zurich CMS PAS QCD M. Guchait DAE-BRNS XIX High Energy Physics.
7 th April 2003PHOTON 2003, Frascati1 Photon structure as revealed in ep collisions Alice Valkárová Institute of Particle and Nuclear Physics Charles University.
Oct 6, 2008Amaresh Datta (UMass) 1 Double-Longitudinal Spin Asymmetry in Non-identified Charged Hadron Production at pp Collision at √s = 62.4 GeV at Amaresh.
Jet Physics at CDF Sally Seidel University of New Mexico APS’99 24 March 1999.
QCD Multijet Study at CMS Outline  Motivation  Definition of various multi-jet variables  Tevatron results  Detector effects  Energy and Position.
A Comparison Between Different Jet Algorithms for top mass Reconstruction Chris Tevlin University of Manchester (Supervisor - Mike Seymour) Atlas UK top.
Chunhui Chen, University of Pennsylvania 1 Heavy Flavor Production and Cross Sections at the Tevatron Heavy Flavor Production and Cross Sections at the.
DIS Conference, Madison WI, 28 th April 2005Jeff Standage, York University Theoretical Motivations DIS Cross Sections and pQCD The Breit Frame Physics.
Event Shapes, Alexander Savin University of WisconsinDIS 2006, April 21, Event Shapes in NC DIS at ZEUS Alexander A. Savin University of Wisconsin.
Jets and α S in DIS Maxime GOUZEVITCH Laboratoire Leprince-Ringuet Ecole Polytechnique – CNRS/IN2P3, France On behalf of the collaboration On behalf of.
April 5, 2003Gregory A. Davis1 Jet Cross Sections From DØ Run II American Physical Society Division of Particles and Fields Philadelphia, PA April 5, 2003.
7/20/07Jiyeon Han (University of Rochester)1 d  /dy Distribution of Drell-Yan Dielectron Pairs at CDF in Run II Jiyeon Han (University of Rochester) For.
Some recent QCD results at the Tevatron N. B. Skachkov (JINR, Dubna)
Measurement of inclusive jet and dijet production in pp collisions at √s = 7 TeV using the ATLAS detector Seminar talk by Eduardo Garcia-Valdecasas Tenreiro.
Jet Studies at CDF Anwar Ahmad Bhatti The Rockefeller University CDF Collaboration DIS03 St. Petersburg Russia April 24,2003 Inclusive Jet Cross Section.
Jet + Isolated Photon Triple Differential Cross Section Nikolay Skachkov: “Photon2007”, Paris, 9-13 July 2007 DO Measurement of Triple Differential Photon.
Don LincolnExperimental QCD and W/Z+Jet Results 1 Recent Dijet Measurements at DØ Don Lincoln Fermi National Accelerator Laboratory for the DØ Collaboration.
Charged Particle Multiplicity, Michele Rosin U. WisconsinQCD Meeting May 13, M. Rosin, D. Kçira, and A. Savin University of Wisconsin L. Shcheglova.
1 Measurement of the Mass of the Top Quark in Dilepton Channels at DØ Jeff Temple University of Arizona for the DØ collaboration DPF 2006.
A. Bertolin on behalf of the H1 and ZEUS collaborations Charm (and beauty) production in DIS at HERA (Sezione di Padova) Outline: HERA, H1 and ZEUS heavy.
Photon and Jet Physics at CDF Jay R. Dittmann Fermi National Accelerator Laboratory (For the CDF Collaboration) 31 st International Conference on High.
Moriond QCD March 24, 2003Eric Kajfasz, CPPM/D01 b-production cross-section at the TeVatron Eric Kajfasz, CPPM/D0 for the CDF and D0 collaborations.
1 Jets in PHENIX Jiangyong Jia, Columbia Univerisity How to measure jet properties using two particle correlation method (In PHENIX)? Discuss formula for.
Mean Charged Multiplicity in DIS, Michele Rosin U. WisconsinZEUS Collaboration Meeting, Oct. 21st Analysis Update: Mean Charged Multiplicity in.
Jet + Isolated Photon Triple Differential Cross Section Nikolay Skachkov: “Photon2007”, Paris, 9-13 July 2007 DO Measurement of Triple Differential Photon.
Search for a Standard Model Higgs Boson in the Diphoton Final State at the CDF Detector Karen Bland [ ] Department of Physics,
F Don Lincoln f La Thuile 2002 Don Lincoln Fermilab Tevatron Run I QCD Results Don Lincoln f.
Recent QCD Measurements at the Tevatron Mike Strauss The University of Oklahoma The Oklahoma Center for High Energy Physics for the CDF and DØ Collaborations.
1 Underlying Event studies & Charged particle multiplicities in inelastic pp events with the ATLAS.
Modern Approach to Monte Carlo’s (L1) The role of resolution in Monte Carlo’s (L1) Leading order Monte Carlo’s (L1) Next-to-Leading order Monte Carlo’s.
Upsilon production and μ-tagged jets in DØ Horst D. Wahl Florida State University (DØ collaboration) 29 April 2005 DIS April to 1 May 2005 Madison.
KIT High Pt Jet Studies with CMS On behalf of the CMS Collaboration Andreas Oehler University of Karlsruhe (KIT) DIS 2009 XVII International Workshop on.
Inclusive jet photoproduction at HERA B.Andrieu (LPNHE, Paris) On behalf of the collaboration Outline: Introduction & motivation QCD calculations and Monte.
Performance of jets algorithms in ATLAS
Measurement of SM V+gamma by ATLAS
Studies of prompt photon identification and 0 isolation in first p-p collisions at √s=10 TeV May 20, 2009 Meeting Frascati Raphaëlle Ichou.
Explore the new QCD frontier: strong color fields in nuclei
Event Shapes in NC DIS at ZEUS
Observation of Diffractively Produced W- and Z-Bosons
Inclusive Jet Cross Section Measurement at CDF
Di-jet production in gg collisions in OPAL
The Tevatron Connection
Observation of Diffractively Produced W- and Z-Bosons
The Underlying Event in Hard Scattering Processes
Inclusive Jet Production at the Tevatron
Measurement of b-jet Shapes at CDF
Presentation transcript:

A Comparison of Three-jet Events in p Collisions to Predictions from a NLO QCD Calculation Sally Seidel QCD’04 July 2004

Three-jet event cross sections have been measured in CDF Run 1b data to: test models of QCD processes leading to gluon emission, and estimate the magnitude of contributing processes higher than NLO. The data are compared to predictions by Trirad ‡, a complete NLO QCD generator for hadronic three-jet production at hadron colliders. ‡ W. Kilgore and W. Giele, hep-ph/

Kinematics and labelling: Define jet transverse energy E T  E sin  relative to primary event vertex. Sum all calorimeter clusters with uncorrected E T > 10 GeV. Consider events with  E T > 175 GeV. Identify the three leading jets in lab system. Boost to their rest frame. Order jets by energy in that rest frame: E 3 > E 4 > E 5.

A three-jet system in the massless parton approximation can be uniquely described by 5 variables. † We use: m 3J : mass of the three-jet system X 3  E 3 /m 3J : Dalitz variable, leading jet X 4  E 4 /m 3J : Dalitz variable, second jet for the angle between average beam direction and parton 3 in the 3-jet frame, and † S. Geer and T. Akasawa, PRD 53, 4793 (1996).

for the angle between the plane containing the average beam direction and the plane containing partons 3, 4, and 5.

Further selection to reject cosmics, beam halo, calorimeter malfunctions — veto if: energy deposited in the Had Cal out of time with the collision  E T > 2000 GeV

Also require: primary vertex has |z| < 60 cm relative to detector origin (to maintain calorimeter projective geometry) and largest  p i. reject events with resolved multiple interactions (having a second vertex of  10 tracks separated by  10 cm from primary). apply iterative cone jet algorithm with cone radius reject events with < 3 jets. 3 leading jets must all have E T > 20 GeV and |  | < 2.0.

To avoid collinear instability, cut on cone overlap: reject events if  R < 1.0 between any 2 of the 3 leading jets. To exclude regions with geometrical acceptance < 95%, require require full trigger efficiency: events remain. sort the events into bins of size 0.02  0.02 in the X 3 - X 4 plane.

Corrections: absolute energy scale, relative energy scale, underlying event z vertex cut efficiency (93%) “unsmear”: simultaneous correction for energy mismeasurement and detector resolution. Generate Herwig events at parton level, hadronize final state, bin in the Dalitz plane, pass through CDF detector simulation, rebin. Compute for each bin: F = #events before sim / #events after Multiply each data bin by F.

The data, after all selection requirements have been applied but prior to the energy correction:

Uncertainties: absolute jet energy scale: due to calorimeter calibration resolution (~1.8%), jet fragmentation model (~1.6%), calorimeter stability (1%), and underlying event correction (~1.1GeV) relative (  -dependent) jet energy scale (~6%) total integrated luminosity (4.2%) z-vertex cut efficiency (2%) implementation of simulated events in the correction procedure (<5%).

The Trirad calculation: 2  3 parton processes at one loop, and 2  4 parton processes at tree level.

The cross section calculation: uses CTEQ4M, for every bin in the Dalitz plane, multiplies the result by the effective total integrated luminosity of the data to predict a #events in each bin, and excludes bins with X 3  0.98: perturbative expansion is not reliable where 3-jet configuration approaches 2-jet. Compare data to prediction for 215 bins.

Data NLO prediction Note some shape difference between data and this absolute (normalized to luminosity) prediction. We compare data to theory in 2 ways...

To compare shapes, normalize theory and data to the same number of events:

To compare absolute cross sections, normalize data and theory to the same luminosity...

Using all bins with X 3  0.98, measured cross section: predicted cross section: Using all bins in the Dalitz plane, measured cross section is

Scale  R default is E T. Scale uncertainty is estimated by varying scale from E T /2 to 2E T while maintaining  R =  F. PDF uncertainty estimated from spread of predictions generated with all members of the CTEQ4A family.

Summary: Data agree in absolute magnitude with theory and with previous CDF measurements. The shapes of the theoretical and experimental Dalitz distributions differ somewhat. This may indicate the size of higher order corrections and may indicate that up to NLO the theory predicts more soft radiation than the data have in the region where the primary partons are approximately back-to-back. The data may be useful input to theoretical models of gluon emission processes, especially above X 3 = 0.98, where a perturbative expansion is not reliable.