XXXVI International Meeting on Fundamental Physics Physics at the Tevatron From IMFP2006 → IMFP2008 Rick Field University of Florida (for the CDF & D0 Collaborations) 1st Lecture FF Phenomenology → Tevatron Jet Physics Palacio de Jabalquinto, Baeza, Spain CDF Run 2 IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Rick Field – Florida/CDF/CMS The Fermilab Tevatron Fermi National Laboratory (Fermilab) is near Chicago, Illinois. CDF and DØ are the the two collider detector experiments at Fermilab. Protons collide with antiprotons at a center-of-mass energy of almost 2 TeV (actually 1.96 TeV). IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Tevatron Performance The data collected since IMFP 2006 more than doubled the total data collected in Run 2! IMFP 2008 ~3.3 fb-1 delivered ~2.8 fb-1 recorded IMFP 2006 ~1.5 fb-1 delivered ~1.2 fb-1 recorded ~1.6 fb-1 Integrated Luminosity per Year 23 tt-pairs/month! Luminosity Records (IMFP 2006): Highest Initial Inst. Lum: ~1.8×1032 cm-2s-1 Integrated luminosity/week: 25 pb-1 Integrated luminosity/month: 92 pb-1 Luminosity records (IMFP 2008): Highest Initial Inst. Lum: ~2.92×1032 cm-2s-1 Integrated luminosity/week: 45 pb-1 Integrated luminosity/month: 165 pb-1 IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Many New Tevatron Results! Some of the CDF Results since IMFP2006 I cannot possibility cover all the great physics results from the Tevatron since IMFP 2006! Observation of Bs-mixing: Δms = 17.77 ± 0.10 (stat) ± 0.07(sys). Observation of new baryon states: Sb and Xb. Observation of new charmless: B→hh states. Evidence for Do-Dobar mixing . Precision W mass measurement: Mw = 80.413 GeV (±48 MeV). Precision Top mass measurement: Mtop = 170.5 (±2.2) GeV. W-width measurement: 2.032 (±0.071) GeV. WZ discovery (6-sigma): s = 5.0 (±1.7) pb. ZZ evidence (3-sigma). Single Top evidence (3-sigma) with 1.5 fb-1: s = 3.0 (±1.2) pb. |Vtb|= 1.02 ± 0.18 (exp) ± 0.07 (th). Significant exclusions/reach on many BSM models. Constant improvement in Higgs Sensitivity. I will show a few of the results! IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

In Search of Rare Processes We might get lucky! We are beginning to measure cross-sections ≤ 1 pb! ~9 orders of magnitude s(pT(jet) > 525 GeV) ≈ 15 fb! PRODUCTION CROSS SECTION (fb) 1 pb W’, Z’, T’ Higgs ED 15 fb IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Toward and Understanding of Hadron-Hadron Collisions Feynman-Field Phenomenology 1st hat! Feynman and Field From 7 GeV/c p0’s to 600 GeV/c Jets. The early days of trying to understand and simulate hadron-hadron collisions. IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Hadron-Hadron Collisions Field-Feynman 1977 (preQCD) What happens when two hadrons collide at high energy? Feynman quote from FF1 “The model we shall choose is not a popular one, so that we will not duplicate too much of the work of others who are similarly analyzing various models (e.g. constituent interchange model, multiperipheral models, etc.). We shall assume that the high PT particles arise from direct hard collisions between constituent quarks in the incoming particles, which fragment or cascade down into several hadrons.” Most of the time the hadrons ooze through each other and fall apart (i.e. no hard scattering). The outgoing particles continue in roughly the same direction as initial proton and antiproton. Occasionally there will be a large transverse momentum meson. Question: Where did it come from? We assumed it came from quark-quark elastic scattering, but we did not know how to calculate it! “Black-Box Model” IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Quark-Quark Black-Box Model No gluons! FF1 1977 (preQCD) Quark Distribution Functions determined from deep-inelastic lepton-hadron collisions Feynman quote from FF1 “Because of the incomplete knowledge of our functions some things can be predicted with more certainty than others. Those experimental results that are not well predicted can be “used up” to determine these functions in greater detail to permit better predictions of further experiments. Our papers will be a bit long because we wish to discuss this interplay in detail.” Quark Fragmentation Functions determined from e+e- annihilations Quark-Quark Cross-Section Unknown! Deteremined from hadron-hadron collisions. IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Quark-Quark Black-Box Model Field-Feynman 1977 (preQCD) Predict particle ratios Predict increase with increasing CM energy W “Beam-Beam Remnants” Predict overall event topology (FFF1 paper 1977) 7 GeV/c p0’s! IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Feynman Talk at Coral Gables (December 1976) 1st transparency Last transparency “Feynman-Field Jet Model” IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

QCD Approach: Quarks & Gluons Quark & Gluon Fragmentation Functions Q2 dependence predicted from QCD FFF2 1978 Feynman quote from FFF2 “We investigate whether the present experimental behavior of mesons with large transverse momentum in hadron-hadron collisions is consistent with the theory of quantum-chromodynamics (QCD) with asymptotic freedom, at least as the theory is now partially understood.” Parton Distribution Functions Q2 dependence predicted from QCD Quark & Gluon Cross-Sections Calculated from QCD IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

High PT Jets CDF (2006) Feynman, Field, & Fox (1978) 30 GeV/c! Predict large “jet” cross-section 30 GeV/c! Feynman quote from FFF “At the time of this writing, there is still no sharp quantitative test of QCD. An important test will come in connection with the phenomena of high PT discussed here.” 600 GeV/c Jets! IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

QCD Monte-Carlo Models: High Transverse Momentum Jets “Hard Scattering” Component “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. The “underlying event” is an unavoidable background to most collider observables and having good understand of it leads to more precise collider measurements! IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Rick Field – Florida/CDF/CMS Collider Coordinates The z-axis is defined to be the beam axis with the xy-plane being the “transverse” plane. qcm is the center-of-mass scattering angle and f is the azimuthal angle. The “transverse” momentum of a particle is given by PT = P cos(qcm). h qcm 90o 1 40o 2 15o 3 6o 4 2o Use h and f to determine the direction of an outgoing particle, where h is the “pseudo-rapidity” defined by h = -log(tan(qcm/2)). The “rapidity” is defined by y = log((E+pz)/(E-pz))/2 and is equal to h in the limit E >> mc2. IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Can also construct jets from the charged particles! Quark & Gluon Jets The CDF calorimeter measures energy deposited in a cell of size DhDf = 0.11×15o, whch is converted into transverse energy, ET = E cos(qcm). “Jets” are defined to be clusters of transverse energy with a radius R in h-f space. A “jet” is the representation in the detector of an outgoing parton (quark or gluon). The sum of the ET of the cells within a “jet” corresponds roughly to the ET of the outgoing parton and the position of the cluster in the grid gives the parton’s direction. Can also construct jets from the charged particles! Calorimeter Jets IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Next-to-leading order parton level calculation Jets at Tevatron “Theory Jets” “Tevatron Jets” Next-to-leading order parton level calculation 0, 1, 2, or 3 partons! Experimental Jets: The study of “real” jets requires a “jet algorithm” and the different algorithms correspond to different observables and give different results! Experimental Jets: The study of “real” jets requires a good understanding of the calorimeter response! Experimental Jets: To compare with NLO parton level (and measure structure functions) requires a good understanding of the “underlying event”! IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Rick Field – Florida/CDF/CMS Jet Corrections Calorimeter Jets: We measure “jets” at the “hadron level” in the calorimeter. We certainly want to correct the “jets” for the detector resolution and effieciency. Also, we must correct the “jets” for “pile-up”. Must correct what we measure back to the true “particle level” jets! Particle Level Jets: Do we want to make further model dependent corrections? Do we want to try and subtract the “underlying event” from the “particle level” jets. This cannot really be done, but if you trust the Monte-Carlo models modeling of the “underlying event” you can try and do it by using the Monte-Carlo models (use PYTHIA Tune A). Parton Level Jets: Do we want to use our data to try and extrapolate back to the parton level? This also cannot really be done, but again if you trust the Monte-Carlo models you can try and do it by using the Monte-Carlo models. The “underlying event” consists of hard initial & final-state radiation plus the “beam-beam remnants” and possible multiple parton interactions. IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Inclusive Jet Cross Section (CDF) Run 1 showed a possible excess at large jet ET (see below). This resulted in new PDF’s with more gluons at large x. The Run 2 data are consistent with the new structure functions (CTEQ6.1M). IMFP2006 Run I CDF Inclusive Jet Data (Statistical Errors Only) JetClu RCONE=0.7 0.1<||<0.7 R=F=ET /2 RSEP=1.3 CTEQ4M PDFs CTEQ4HJ PDFs CTEQ4HJ CTEQ4M IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Inclusive Jet Cross Section (CDF) MidPoint Cone Algorithm (R = 0.7, fmerge = 0.75) Data corrected to the hadron level L = 1.04 fb-1 0.1 < |yjet| < 0.7 Compared with NLO QCD IMFP2006 today 1.13 fb-1 s(pT > 525 GeV) ≈ 15 fb! Sensitive to UE + hadronization effects for PT < 200 GeV/c! IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Rick Field – Florida/CDF/CMS KT Algorithm kT Algorithm: Cluster together calorimeter towers by their kT proximity. Infrared and collinear safe at all orders of pQCD. No splitting and merging. No ad hoc Rsep parameter necessary to compare with parton level. Every parton, particle, or tower is assigned to a “jet”. No biases from seed towers. Favored algorithm in e+e- annihilations! KT Algorithm Will the KT algorithm be effective in the collider environment where there is an “underlying event”? Raw Jet ET = 533 GeV Raw Jet ET = 618 GeV CDF Run 2 Only towers with ET > 0.5 GeV are shown IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

KT Inclusive Jet Cross Section (CDF) KT Algorithm (D = 0.7) Data corrected to the hadron level L = 385 pb-1 0.1 < |yjet| < 0.7 Compared with NLO QCD. IMFP2006 today 1.0 fb-1 Sensitive to UE + hadronization effects for PT < 200 GeV/c! IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Big uncertainty for high-x gluon PDF! from Run I Forward jets measurements put constraints on the high x gluon distribution! Big uncertainty for high-x gluon PDF! Uncertainty on gluon PDF (from CTEQ6) x Forward Jets high x low x IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

KT Forward Jet Cross Section (CDF) KT Algorithm (D = 0.7). Data corrected to the hadron level. L = 385 pb-1. Five rapidity regions: |yjet| < 0.1 0.1 < |yjet| < 0.7 0.7 < |yjet| < 1.1 1.1 < |yjet| < 1.6 1.6 < |yjet| < 2.1 Compared with NLO QCD today 1.0 fb-1 IMFP2006 IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Forward Jet Cross Section (CDF) since IMFP2006 New MidPoint Cone Algorithm (R = 0.7, fmerge = 0.75) Data corrected to the hadron level L = 1.13 pb-1. Five rapidity regions: |yjet| < 0.1 0.1 < |yjet| < 0.7 0.7 < |yjet| < 1.1 1.1 < |yjet| < 1.6 1.6 < |yjet| < 2.1 Compared with NLO QCD 1.0 fb-1 IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Inclusive Jet Cross Section (DØ ) MidPoint Cone Algorithm (R = 0.7, fmerge = 0.5) L = 378 pb-1 Two rapidity bins Highest PT jet is 630 GeV/c Compared with NLO QCD (JetRad, No Rsep) today 0.9 fb-1 IMFP2006 Log-Log Scale! IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Without threshold corrections! CDF versus DØ Without threshold corrections! Inclusive Jet (CDF) Inclusive Jet (DØ) MidPoint Cone Algorithm (R = 0.7, fmerge = 0.75) CTEQ6.1M m = PT/2 MidPoint Cone Algorithm (R = 0.7, fmerge = 0.5) CTEQ6.1M m = PT Threshold corrections (2 loops) IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

DiJet Cross Section (CDF) since IMFP2006 New CDF Run II Preliminary MidPoint Cone Algorithm (R = 0.7, fmerge = 0.75) Data corrected to the hadron level L = 1.13 fb-1 |yjet1,2| < 1.0 Compared with NLO QCD Sensitive to UE + hadronization effects! IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Inclusive Jet versus DiJet (CDF) Inclusive Jet (CDF) DiJet (CDF) MidPoint Cone Algorithm (R = 0.7, fmerge = 0.75) CTEQ6.1M m = PT/2 MidPoint Cone Algorithm (R = 0.7, fmerge = 0.75) CTEQ6.1M m = mean(PT1,PT2) IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

CDF DiJet Event: M(jj) ≈ 1.4 TeV ETjet1 = 666 GeV ETjet2 = 633 GeV Esum = 1,299 GeV M(jj) = 1,364 GeV Exclusive p+p → p+p+e++e- (16 events) s = 1.6 ± 0.3 pb since IMFP2006 New M(jj)/Ecm ≈ 70%!! CDF Run II IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

“Towards”, “Away”, “Transverse” Look at the charged particle density, the charged PTsum density and the ETsum density in all 3 regions! Df Correlations relative to the leading jet Charged particles pT > 0.5 GeV/c |h| < 1 Calorimeter towers ET > 0.1 GeV |h| < 1 “Transverse” region is very sensitive to the “underlying event”! Look at correlations in the azimuthal angle Df relative to the leading charged particle jet (|h| < 1) or the leading calorimeter jet (|h| < 2). Define |Df| < 60o as “Toward”, 60o < |Df| < 120o as “Transverse ”, and |Df| > 120o as “Away”. Each of the three regions have area DhDf = 2×120o = 4p/3. IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Event Topologies Rick Field & Craig Group CDF-QCD Data for Theory 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-hadron collisions. Rick Field & Craig Group “Leading Jet” events correspond to the leading calorimeter jet (MidPoint R = 0.7) in the region |h| < 2 with no other conditions. “Leading Jet” subset “Back-to-Back Inclusive 2-Jet” events are selected to have at least two jets with Jet#1 and Jet#2 nearly “back-to-back” (Df12 > 150o) with almost equal transverse energies (PT(jet#2)/PT(jet#1) > 0.8) with no other conditions . “Back-to-Back Inc2J” “Back-to-Back Exclusive 2-Jet” events are selected to have at least two jets with Jet#1 and Jet#2 nearly “back-to-back” (Df12 > 150o) with almost equal transverse energies (PT(jet#2)/PT(jet#1) > 0.8) and PT(jet#3) < 15 GeV/c. subset “Back-to-Back Exc2J” “Charged Jet” “Leading ChgJet” events correspond to the leading charged particle jet (R = 0.7) in the region |h| < 1 with no other conditions. IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Overall Totals (|h| < 1) ETsum = 775 GeV! “Leading Jet” ETsum = 330 GeV PTsum = 190 GeV/c Nchg = 30 Data at 1.96 TeV on the overall number of charged particles (pT > 0.5 GeV/c, |h| < 1) and the overall scalar pT sum of charged particles (pT > 0.5 GeV/c, |h| < 1) and the overall scalar ET sum of all particles (|h| < 1) for “leading jet” events as a function of the leading jet pT. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A at the particle level (i.e. generator level).. IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

“Towards”, “Away”, “Transverse” “Leading Jet” Factor of ~13 Factor of ~16 Factor of ~4.5 Data at 1.96 TeV on the charged particle scalar pT sum density, dPT/dhdf, with pT > 0.5 GeV/c and |h| < 1 for “leading jet” events as a function of the leading jet pT for the “toward”, “away”, and “transverse” regions. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A at the particle level (i.e. generator level). Data at 1.96 TeV on the density of charged particles, dN/dhdf, with pT > 0.5 GeV/c and |h| < 1 for “leading jet” events as a function of the leading jet pT for the “toward”, “away”, and “transverse” regions. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A at the particle level (i.e. generator level). Data at 1.96 TeV on the particle scalar ET sum density, dET/dhdf, for |h| < 1 for “leading jet” events as a function of the leading jet pT for the “toward”, “away”, and “transverse” regions. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A at the particle level (i.e. generator level). IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Rick Field – Florida/CDF/CMS The “Toward” Region “Leading Jet” Data at 1.96 TeV on the charged scalar pT sum density, dPT/dhdf, with pT > 0.5 GeV/c and |h| < 1 for “leading jet” events as a function of the leading jet pT for the “toward” region. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A and HERWIG (without MPI) at the particle level (i.e. generator level). Data at 1.96 TeV on the density of charged particles, dN/dhdf, with pT > 0.5 GeV/c and |h| < 1 for “leading jet” events as a function of the leading jet pT for the “toward” region. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A and HERWIG (without MPI) at the particle level (i.e. generator level). Data at 1.96 TeV on the scalar ET sum density, dET/dhdf, with |h| < 1 for “leading jet” events as a function of the leading jet pT for the “toward” region. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A and HERWIG (without MPI) at the particle level (i.e. generator level). IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Rick Field – Florida/CDF/CMS The “Away” Region “Leading Jet” Data at 1.96 TeV on the charged scalar pT sum density, dPT/dhdf, with pT > 0.5 GeV/c and |h| < 1 for “leading jet” events as a function of the leading jet pT for the “away” region. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A and HERWIG (without MPI) at the particle level (i.e. generator level). Data at 1.96 TeV on the density of charged particles, dN/dhdf, with pT > 0.5 GeV/c and |h| < 1 for “leading jet” events as a function of the leading jet pT for the “away” region. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A and HERWIG (without MPI) at the particle level (i.e. generator level). Data at 1.96 TeV on the scalar ET sum density, dET/dhdf, with |h| < 1 for “leading jet” events as a function of the leading jet pT for the “away” region. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A and HERWIG (without MPI) at the particle level (i.e. generator level). IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

The “Transverse” Region “Leading Jet” Data at 1.96 TeV on the charged scalar pT sum density, dPT/dhdf, with pT > 0.5 GeV/c and |h| < 1 for “leading jet” events as a function of the leading jet pT for the “transverse” region. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A and HERWIG (without MPI) at the particle level (i.e. generator level). Data at 1.96 TeV on the density of charged particles, dN/dhdf, with pT > 0.5 GeV/c and |h| < 1 for “leading jet” events as a function of the leading jet pT for the “transverse” region. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A and HERWIG (without MPI) at the particle level (i.e. generator level). Data at 1.96 TeV on the scalar ET sum density, dET/dhdf, with |h| < 1 for “leading jet” events as a function of the leading jet pT for the “transverse” region. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A and HERWIG (without MPI) at the particle level (i.e. generator level). Data at 1.96 TeV on the charged particle maximum pT, with pT > 0.5 GeV/c and |h| < 1 for “leading jet” events as a function of the leading jet pT for the “transverse” region. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A and HERWIG (without MPI) at the particle level (i.e. generator level). Data at 1.96 TeV on the charged particle average pT, with pT > 0.5 GeV/c and |h| < 1 for “leading jet” events as a function of the leading jet pT for the “transverse” region. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A and HERWIG (without MPI) at the particle level (i.e. generator level). IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

The “Transverse” Region “Leading Jet” 0.1 density corresponds to 0.42 charged particles in the “transverse” region! Data at 1.96 TeV on the density of charged particles, dN/dhdf, with pT > 0.5 GeV/c and |h| < 1 for “leading jet” events as a function of the leading jet pT for the “transverse” region. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A and HERWIG (without MPI) at the particle level (i.e. generator level). Shows the Data - Theory for the density of charged particles, dN/dhdf, with pT > 0.5 GeV/c and |h| < 1 for “leading jet” events as a function of the leading jet pT for the “transverse” region for PYTHIA Tune A and HERWIG (without MPI). IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

The “Transverse” Region “Leading Jet” 0.1 density corresponds to 420 MeV/c in the “transverse” region! Data at 1.96 TeV on the charged scalar pT sum density, dPT/dhdf, with pT > 0.5 GeV/c and |h| < 1 for “leading jet” events as a function of the leading jet pT for the “transverse” region. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A and HERWIG (without MPI) at the particle level (i.e. generator level). Shows the Data - Theory for the charged scalar pT sum density, dPT/dhdf, with pT > 0.5 GeV/c and |h| < 1 for “leading jet” events as a function of the leading jet pT for the “transverse” region for PYTHIA Tune A and HERWIG (without MPI). IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

The “Transverse” Region “Leading Jet” 0.4 density corresponds to 1.67 GeV in the “transverse” region! Data at 1.96 TeV on the scalar ET sum density, dET/dhdf, with |h| < 1 for “leading jet” events as a function of the leading jet pT for the “transverse” region. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A and HERWIG (without MPI) at the particle level (i.e. generator level). Shows the Data - Theory for the scalar ET sum density, dET/dhdf, with |h| < 1 for “leading jet” events as a function of the leading jet pT for the “transverse” region for PYTHIA Tune A and HERWIG (without MPI). IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Rick Field – Florida/CDF/CMS The Leading Jet Mass “Leading Jet” Off by ~2 GeV Data at 1.96 TeV on the leading jet invariant mass for “leading jet” events as a function of the leading jet pT. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A and HERWIG (without MPI) at the particle level (i.e. generator level). Shows the Data - Theory for the leading jet invariant mass for “leading jet” events as a function of the leading jet pT for PYTHIA Tune A and HERWIG (without MPI). IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

The “Transverse” Region “Leading Jet” PT(min) = 0 → 0.5 GeV/c Shows the generator level predictions for the charged fraction, PTsum/ETsum, for PTsum (all pT, |h| < 1) and ETsum (all pT, |h| < 1) and for PTsum (pT > 0.5 GeV/c, |h| < 1) and ETsum (all pT, |h| < 1) for “leading jet” events as a function of the leading jet pT for the “transverse” region from PYTHIA Tune A and HERWIG (without MPI). Data at 1.96 TeV on the charged fraction, PTsum/ETsum, for PTsum (pT > 0.5 GeV/c, |h| < 1) and ETsum (all pT, |h| < 1) for “leading jet” events as a function of the leading jet pT for the “transverse” region. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A and HERWIG (without MPI) at the particle level (i.e. generator level). IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

bb DiJet Cross Section (CDF) ≈ 85% purity! Collision point b-quark tag based on displaced vertices. Secondary vertex mass discriminates flavor. Require two secondary vertex tagged b-jets within |y|< 1.2 and study the two b-jets (Mjj, Dfjj, etc.). IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

The Sources of Heavy Quarks Leading-Log Order QCD Monte-Carlo Model (LLMC) Leading Order Matrix Elements We do not observe c or b quarks directly. We measure D-mesons (which contain a c-quark) or we measure B-mesons (which contain a b-quark) or we measure c-jets (jets containing a D-meson) or we measure b-jets (jets containing a B-meson). (structure functions) × (matrix elements) × (Fragmentation) + (initial and final-state radiation: LLA) IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Other Sources of Heavy Quarks “Flavor Excitation” (LLMC) corresponds to the scattering of a b-quark (or bbar-quark) out of the initial-state into the final-state by a gluon or by a light quark or antiquark. “Gluon-Splitting” (LLMC) is where a b-bbar pair is created within a parton shower or during the the fragmentation process of a gluon or a light quark or antiquark. Here the QCD hard 2-to-2 subprocess involves only gluons and light quarks and antiquarks. In the leading-log order Monte-Carlo models (LLMC) the separation into “flavor creation”, “flavor excitation”, and “gluon splitting” is unambiguous, however at next to leading order the same amplitudes contribute to all three processes! and there are interference terms! Next to Leading Order Matrix Elements 2 s(gg→QQg) = Amp(gg→QQg) = + + IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

bb DiJet Cross Section (CDF) IMFP2006 ET(b-jet#1) > 35 GeV, ET(b-jet#2) > 32 GeV, |h(b-jets)| < 1.2. Preliminary CDF Results: sbb = 34.5  1.8  10.5 nb QCD Monte-Carlo Predictions: PYTHIA Tune A CTEQ5L 38.7 ± 0.6 nb HERWIG CTEQ5L 21.5 ± 0.7 nb MC@NLO 28.5 ± 0.6 nb MC@NLO + Jimmy 35.7 ± 2.0 nb Differential Cross Section as a function of the b-bbar DiJet invariant mass! JIMMY Runs with HERWIG and adds multiple parton interactions! Proton AntiProton “Flavor Creation” b-quark Underlying Event Initial - State Radiation Final State Radiation JIMMY: MPI J. M. Butterworth J. R. Forshaw M. H. Seymour Adding multiple parton interactions (i.e. JIMMY) to enhance the “underlying event” increases the b-bbar jet cross section! IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

bb DiJet Cross Section (CDF) since IMFP2006 New ET(b-jet#1) > 35 GeV, ET(b-jet#2) > 32 GeV, |h(b-jets)| < 1.2. Systematic Uncertainty Preliminary CDF Results: sbb = 5664  168  1270 pb QCD Monte-Carlo Predictions: PYTHIA Tune A CTEQ5L 5136 ± 52 pb HERWIG CTEQ5L+Jimmy 5296 ± 98 pb MC@NLO+Jimmy 5421 ± 105 nb Predominately Flavor creation! Sensitive to the “underlying event”! IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

bb DiJet Df Distribution (CDF) since IMFP2006 New Large Df (i.e. b-jets are “back-to-back”) is predominately “flavor creation”. Small Df (i.e. b-jets are near each other) is predominately “flavor excitation” and “gluon splitting”. It takes NLO + “underlying event” to get it right! IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

Z + b-Jet Production (CDF) since IMFP2006 New IMFP2006 Important background for new physics! Leptonic decays for the Z. Z associated with jets. CDF: JETCLU, D0: R = 0.7, |hjet| < 1.5, ET >20 GeV Look for tagged jets in Z events. L = 335 pb-1 today 1.5 fb-1 Extract fraction of b-tagged jets from secondary vertex mass distribution: NO assumption on the charm content. Observable CDF Data PYTHIA Tune A MCFM NLO (+UE) s(Z+b-jet) 0.94±0.15±0.15 pb -- 0.51 (0.56) pb s(Z+b-jet)/s(Z) 0.369±0.057±0.055 % 0.35% 0.21 (0.23) % s(Z+b-jet)/s(Z+jet) 2.35±0.36±0.45 % 2.18% 1.88 (1.77) % Sensitive to the “underlying event”! IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS

XXXVI International Meeting on Fundamental Physics Physics at the Tevatron From IMFP2006 → IMFP2008 Rick Field University of Florida (for the CDF & D0 Collaborations) 2nd Lecture (Tomorrow) Bosons, Top, and Higgs Palacio de Jabalquinto, Baeza, Spain CDF Run 2 IMFP2008 - Day 1 February 4, 2008 Rick Field – Florida/CDF/CMS