1 / 16

Jets at the LPC

Jets at the LPC. Robert M. Harris Fermilab Jet Week at Fermilab Theory Group August 24, 2009. 1. Outline. The LHC Physics Center JetMET working group at LPC Dijet Topology Group at LPC Conclusions. Disclaimer. There are a wide variety of LPC activities associated with jets.

hollye
Download Presentation

Jets at the LPC

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Jets at the LPC Robert M. Harris Fermilab Jet Week at Fermilab Theory Group August 24, 2009 1

  2. Outline • The LHC Physics Center • JetMET working group at LPC • Dijet Topology Group at LPC • Conclusions Robert Harris, Fermilab

  3. Disclaimer • There are a wide variety of LPC activities associated with jets. • Jets are ubiquitous • Many LPC subgroups have done work on jets • Many calorimeter activities are directly related to jets • I apologize in advance for not covering all this work here • Here I will concentrate on a few areas • Only CMS approved results • Mainly physics analysis, primarily of dijets • Approved results on jet performance will be shown on Thursday • Talk on “Jets at CMS” immediately following Peter’s talk on “Jets at ATLAS” Robert Harris, Fermilab

  4. LHC Physics Center (LPC) • The LPC is a center of CMS physics in the USA • Centered at one “brick and mortar” location are • CMS experts in Physics object reconstruction. • Object working groups: JetMET, e/g, m, t, tracking, btagging. • CMS efforts in Physics analysis • Signature based topology groups: dijet, dilepton, Jet+MET, g+X, lepton + jet + MET • Benefitting from the expertise in hadron colliders here at Fermilab • Powerful computing (T1 + T3) that facilitates physics analysis • Remote operations center (ROC) monitoring the detector • Providing organizational and educational services to CMS • Workshops and tutorials in addition to regular meetings • Mentoring of graduate students and postdocs • Theorist of the week and strong ties to the FNAL theory group Robert Harris, Fermilab

  5. LPC Organization Chart • US CMS LPC AB • G&V • Fellows • Housing • Offices CMS US CMS US CMS RP CMS Center @ FNAL LPC Facilitators (I. Shipsey, D. Green) • Enabling Analysis • Trigger (K. Maeshima, L. Apanasevich) • ROC, DQM (K. Maeshima, N. Hadley) • Gen/Simul ( H. Cheung, A. Kharchilava, S. Mrenna) • Physics Support ( L. Sexton, P. Maksimovic) • DPGs & POGs • Tracking (K. Burkett, S. Wagner) • b tag/Vertex (C. Gerber, A. Dominguez) • e/gamma (C. Jessop, J. Berryhill) • Muon ( E. James, M. Schmitt) • Tau ( A. Safonov, A. Anastassov) • Jet/MET (M. Zielinski, F. Chlebana) • Physics Topologies • J+J (R. Harris, J. Nachtman) • J+MET (A. Bhatti, T. Kamon) • +J, + (A. Askew, M. Gataullin) • ℓ+J+MET (K. Bloom, M. Narain) • ℓ+ℓ (V. Halyo, Y. Maravin) Legend ℓ Stakeholders Working groups Data Ops LPC Physics Forum B. Klima, Y. Gershtein Points of contact Educaton & Outreach (D.Lincoln,R.Ruchti) LHC (J. Strait) Theory (B. Kilminster) USCMS Phys. Coordinator (Y.Gershtein) Robert Harris, Fermilab

  6. JetMET working group Details On Thursday at LPC Examples in this talk • Working group formed in 2005 at LPC • Concentrated on basics of jets and jet physics • Calorimeter cell energy thresholds • Software and algorithms for jet reconstruction • Jet energy corrections • Jet resolutions and efficiencies • Jet trigger • Dijet physics before the formation of topology groups • By 2008 group had been absorbed into international CMS JetMET • LPC effort was a majority of the international CMS effort on jets • Meetings became international with little distinction between LPC and CMS Robert Harris, Fermilab

  7. |jet h|<1 Early Jet Work at LPC: Triggers and Dijet Mass at √s = 14 TeV Prescaled Trigger Samples • Prepared CMS to measure jet spectrum with triggers, and studied the uncertainties (2005) • Published in physics TDR J.Phys.G34:995-1579,2007. Robert Harris, Fermilab

  8. Early Jet Work at LPC: Dijet Resonance at √s = 14 TeV 95% CL Sensitivity to Dijet Resonances Tevatron Exclusion (Dijets) CMS 100 pb-1 CMS 1 fb-1 CMS 10 fb-1 E6 Diquark Excited Quark Axigluon or Coloron Color Octet Technirho W ’ R S Graviton Z ’ J.Phys.G34:995-1579,2007. 0 1 2 3 4 5 6 Mass (TeV) Early study of search for resonances in the dijet mass spectrum (2006) Robert Harris, Fermilab

  9. Early Jet Work at LPC: Dijet Ratio at √s = 14 TeV Dijet Ratio and Contact Interactions Dijet Ratio and Resonances L+ (TeV) 3 5 10 QCD 95% CL L<8.3 TeV, 5s L<6.8 TeV • Early study of search for contact interactions and resonances with simple dijet angular measurements (2007) • Dijet Ratio = N(|h|<0.7) / N(0.7<|h|<1.3) is sensitive to angular distribution • Publicly available in CMS Physics Analysis Summary SBM-07-001 Robert Harris, Fermilab

  10. Required Corrections Optional Corrections Reconstructed Jets Calibrated Jets Offset Parton Rel: h Abs: pT EMF Flavor UE Recent Jet Work at LPC:Corrections, Resolutions and Efficiencies • Factorizing the correction into pieces that are measured in collider data: • Offset: pile-up and noise measured in zero-bias events. • Relative: jet response vs. h relative to barrel found using dijet balance, etc. • Absolute: jet response vs. PT found in barrel using g / Z + jets, top, etc. • Many of the factors are being measured at the LPC • Results publicly available in 7 Physics Analysis Summaries • Data driven methods for measuring jet resolution and efficiency • Details in talk “Jets at CMS” Thursday afternoon at LPC • We have lead the development of jet energy corrections at CMS • Applying the experience of the Tevatron to the LHC environment. Robert Harris, Fermilab

  11. Jet 2 Jet 1 ET h f -1 0 1 Dijet Topology Group • Since 2008 concentrated on measuring dijet process • Test QCD • Search for physics beyond SM • Continuation of earlier analyses begun in JetMET • Dijet Mass and Ratio • Search for resonances and quark contact interactions • Background suppression • New analyses focused more on QCD with CMS/QCD group • Inclusive jet pt distribution • Dijet azimuthal decorrelations • Dijet angular distribution • Jet Shapes Dijet Event (m = 900 GeV) Robert Harris, Fermilab

  12. Background Suppression • Studied MET/SET to reject cosmic rays, detector noise, and beam halo. • Publicly available in CMS PAS QCD-08-001. Robert Harris, Fermilab

  13. Inclusive Jet PT at √s = 10 TeV • Flagship jet analysis and its uncertainties with 10 pb-1 • Classic test of NLO QCD and search for contact interactions • Dominated by jet energy uncertainties at CMS startup • Publicly available in CMS PAS QCD-08-001 Robert Harris, Fermilab

  14. Dijet Azimuthal Decorrelations at √s = 10 TeV • Dijet Df distribution sensitive to higher orders of QCD • Can be used to tune level of QCD radiation in Monte Carlo • Publicly available in CMS PAS QCD-09-003 Robert Harris, Fermilab

  15. Jet Shapes at √s = 14 TeV Fraction of Jet Energy outside r=0.2 • Measurement of energy in annulus about jet axis • Sensitive to parton showering models for quarks and gluons • Publicly available in CMS PAS QCD-08-002 Robert Harris, Fermilab

  16. Conclusions • The LPC is a center of CMS Physics in the USA • Jets are actively being studied at LPC. • This work is well integrated into the CMS physics organization. • Producing CMS approved and publicly available results • We are preparing for the basic jet physics measurements • Inclusive jets • Dijet Mass • Dijet Angular Measurements • We eagerly anticipate searching for new physics with jets. Robert Harris, Fermilab

More Related