Studying the “Underlying Event” at CDF

Studying the “Underlying Event” at CDF “Leading Jet” vs Z-Boson Rick Field University of Florida Outline of Talk CDF Run 2 ◻The “Towards”, “Away”, and “Transverse” regions of η-φ space. ◻Four Jet Topologies. ◻The “transMAX” and “transMIN” regions. ◻The “underlying event” in Drell-Yan production. “Leading Jet” Proton Underlying Event Outgoing Parton Final-State Radiation Outgoing Parton PT(hard) Initial-State Radiation AntiProton Underlying Event ◻The observables: First look at average quantities. Then do Drell-Yan Production Lepton distributions. ◻Look at

versus Nchg in “min-bias” and Drell-Yan. Proton Underlying Event AntiProton Underlying Event ◻Show some extrapolations of Drell-Yan to the LHC. Anti-Lepton Fourth HERA-LHC Workshop Rick Field – Florida/CDF/CMS Page 1 May 26-30, 2008 Studying the “Underlying Event” at CDF “Leading Jet” vs Z-Boson Rick Field University of Florida Outline of Talk CDF Run 2 The goal is to produce data (corrected to the particle level) that can be used by the theorists to tune and improve the QCD Monte-Carlo models that are used to simulate hadron-hadront ◻The “transMAX” and “transMIN” regions. Outgoing Parton PT(hard) Initial-State Radiation AntiProton Underlying Event ◻The “underlying event” in Drell-Yan production. ield Outgoing Parton Final-State Radiation ◻The observables: First look at average quantities. Then do Drell-Yan Production distributions. Deepak Kar ◻Look-at versus Nchg in “min-bias” and Underlying Event Lepton AntiProton Underlying Event ◻Show some extrapolations of Drell-Yan to the LHC. Anti-Lepton Fourth HERA-LHC Workshop Rick Field – Florida/CDF/CMS Page 2 May 26-30, 2008 QCD Monte-Carlo Models: High Transverse Momentum Jets Hard Scattering Initial-State Radiation Outgoing Parton PT(hard) Hard Scattering Initial-State Radiation Outgoing Parton PT(hard) “Hard Scattering” Component Proton Underlying Event AntiProton Underlying Event Final-State Radiation Outgoing Parton Final-State Radiation Outgoing Parton Proton Underlying Event AntiProton Underlying Event “Underlying Event” ◻Start with the perturbative 2-to-2 (or sometimes 2-to-3) parton-parton scattering and add initial and final-state gluon radiation (in the leading log approximation or modified leading log approximation). ◻The “underlying event” consists of the “beam-beam remnants” and from particles arising from soft or semi-soft multiple parton interactions (MPI). ◻Of course the outgoing colored partons fragment into hadron “jet” and inevitably “underlying event” observables receive contributions from initial and final-state radiation. Fourth HERA-LHC Workshop Rick Field – Florida/CDF/CMS Page 3 May 26-30, 2008 QCD Monte-Carlo Models: High Transverse Momentum Jets Hard Scattering Initial-State Radiation Outgoing Parton PT(hard) Hard Scattering “Jet” Outgoing Parton Initial-State Radiation PT(hard) “Hard Scattering” Component Proton Underlying Event AntiProton Underlying Event Final-State Radiation Outgoing Parton “Final-State Radiation Outgoing Parton Proton Underlying Event AntiProton Underlying Event “Underlying Event” ◻Start with the perturbative 2-to-2 (or sometimes 2-to-3) parton-parton scattering and add initial and final-state gluon radiation (in the leading log approximation or modified leading log approximation). ◻The “underlying event” consists of the “beam-beam remnants” and from particles arising from soft or semi-soft multiple parton interactions (MPI). ◻Of course the outgoing colored partons fragment into hadron i“jet” andi inevitably “underlying event” observables receive contributions from initial and final-state radiation.ads to more precise collider measurements! Fourth HERA-LHC Workshop Rick Field – Florida/CDF/CMS Page 4 May 26-30, 2008 QCD Monte-Carlo Models: Lepton-Pair Production Lepton-Pair Production Anti-Lepton Initial-State Radiation Lepton-Pair Production Anti-Lepton Initial-State Radiation “Hard Scattering” Component Proton Underlying Event AntiProton Lepton Underlying Event Proton Lepton Underlying Event AntiProton Underlying Event “Underlying Event” ◻Start with the perturbative Drell-Yan muon pair production and add initial-state gluon radiation (in the leading log approximation or modified leading log approximation). ◻The “underlying event” consists of the “beam-beam remnants” and from particles arising from soft or semi-soft multiple parton interactions (MPI). ◻Of course the outgoing colored partons fragment into hadron “jet” and inevitably “underlying event” observables receive contributions from initial and final-state radiation. Fourth HERA-LHC Workshop Rick Field – Florida/CDF/CMS Page 5 May 26-30, 2008 ... - tailieumienphi.vn