A.M. Baldin seminar series. XXI Baldin Seminar Retrospective A few historical remarks by Lee Pondrom.

Slides:



Advertisements
Similar presentations
Niccolo’ Moggi XII DIS April The “Underlying Event” at CDF Niccolo’ Moggi Universita’ and I.N.F.N, Bologna for the CDF Collaboration April 15,
Advertisements

INTRODUCTION TO e/ ɣ IN ATLAS In order to acquire the full physics potential of the LHC, the ATLAS electromagnetic calorimeter must be able to identify.
Ultra Peripheral Collisions at RHIC Coherent Coupling Coherent Coupling to both nuclei: photon~Z 2, Pomeron~A 4/3 Small transverse momentum p t ~ 2h 
Jet and Jet Shapes in CMS
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.
IMFP Day 4 April 6, 2006 Rick Field – Florida/CDF/CMSPage 1 XXXIV International Meeting on Fundamental Physics Rick Field University of Florida (for.
Top Turns Ten March 2 nd, Measurement of the Top Quark Mass The Low Bias Template Method using Lepton + jets events Kevin Black, Meenakshi Narain.
Kevin Black Meenakshi Narain Boston University
Interjet Energy Flow at ZEUS. Patrick Ryan. Univ. of Wisconsin DPF, Aug. 27, Patrick Ryan University of Wisconsin Aug. 27, 2004 Interjet Energy.
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.
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”.
1 Introduction to Dijet Resonance Search Exercise John Paul Chou, Eva Halkiadakis, Robert Harris, Kalanand Mishra and Jason St. John CMS Data Analysis.
A.M. Baldin seminar series. XXI Baldin Seminar Retrospective A few historical remarks by Lee Pondrom.
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.
Jet Physics in ALICE Mercedes López Noriega - CERN for the ALICE Collaboration Hot Quarks 2006 Villasimius, Sardinia - Italy.
C2CR07-Lake Tahoe February 28, 2007 Rick Field – Florida/CDFPage 1 C2CR07 Rick Field University of Florida (for the CDF Collaboration) CDF Run 2 Min-Bias.
Searches for double partons Lee Pondrom University of Wisconsin July 23, 2012.
1 Correlations between J/ψ and charged hadrons Chun Zhang / Jiangyong Jia.
Transverse Single-Spin Asymmetries Understanding the Proton: One of the fundamental building blocks of ordinary matter! Spin decomposition of proton still.
St. Andrews, Scotland August 22, 2011 Rick Field – Florida/CDF/CMSPage Rick Field University of Florida Outline  Do we need a.
The Underlying Event in Jet Physics at TeV Colliders Arthur M. Moraes University of Glasgow PPE – ATLAS IOP HEPP Conference - Dublin, 21 st – 23 rd March.
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.
Andrei Rostovtsev Moscow, ITEP December, 2010 Systematic study of inclusive hadron production spectra in collider experiments Workshop on Hadron-Hadron.
Recent multiplicity studies at ZEUS, Michele Rosin U. WisconsinHadron Structure 2004, Sept. 1st University of Wisconsin, Madison on behalf of the.
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.
CDF Paper Seminar Fermilab - March 11, 2010 Rick Field – Florida/CDF/CMSPage 1 Sorry to be so slow!! Studying the “Underlying Event” at CDF CDF Run 2 “Leading.
Cascade production – preliminary results Cascades  and  are reconstructed in decay chain   and  K, respectively. Plots in the first row show mass.
Oct. 12, 2007 Imran Younus k T Asymmetry in Longitudinally Polarized p +p Collisions at PHENIX.
Andrey Korytov, University of Florida EPS 2003 July 17-23, 2003, Aachen Soft QCD Phenomena in High-E T Jet Events at CDF Abstracts covered in this talk.
1 Experimental Particle Physics PHYS6011 Fergus Wilson, RAL 1.Introduction & Accelerators 2.Particle Interactions and Detectors (2) 3.Collider Experiments.
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.
Run 2 Jets at the Tevatron Iain Bertram Lancaster University/DØ Experiment PIC2003  Inclusive Cross Section  Dijet Mass  Structure.
Jet Production in Au+Au Collisions at STAR Alexander Schmah for the STAR Collaboration Lawrence Berkeley National Lab Hard Probes 2015 in Montreal/Canada.
ISMD2004 July 27, 2004 Rick Field - Florida/CDFPage 1 International Symposium on Multiparticle Dynamics Rick Field (theorist?) “Jet Formation in QCD”
on behalf of the CDF and DØ collaborations
Searches for double partons
Implications of First LHC Data: Underlying Event Measurements
Analysis Update: Mean Charged Multiplicity in DIS
Lake Louise Winter Institute
A Closer Look at the Underlying Event in Run 2 at CDF
The “Underlying Event” in Run 2 (CDF)
MB&UE Working Group Meeting CMS UE Data and the New Tune Z1
Predicting MB & UE at the LHC
Event Shape Analysis in minimum bias pp collisions in ALICE.
Di-jet production in gg collisions in OPAL
Modeling Min-Bias and Pile-Up University of Oregon February 24, 2009
Experimental Particle Physics PHYS6011 Putting it all together Lecture 4 6th May 2009 Fergus Wilson, RAL.
Event Shape Variables in DIS Update
Predicting “Min-Bias” and the “Underlying Event” at the LHC
Lee Pondrom, U. of Wisconsin, for the CDF Collaboration
Min-Bias and the Underlying Event in Run 2
“Min-Bias” and the “Underlying Event” in Run 2 at CDF and the LHC
Experimental Particle Physics PHYS6011 Putting it all together Lecture 4 28th April 2008 Fergus Wilson. RAL.
XXXIV International Meeting on Fundamental Physics
The “Underlying Event” in Run 2 at CDF
Experimental Particle Physics PHYS6011 Joel Goldstein, RAL
International Symposium on Multiparticle Dynamics
“Min-Bias” & “Underlying Event” at the Tevatron and the LHC
The Underlying Event in Hard Scattering Processes
Perspectives on Physics and on CMS at Very High Luminosity
PYTHIA 6.2 “Tunes” for Run II
Rick Field - Florida/CDF
Tracks and double partons
Tracks and double partons
Measurement of b-jet Shapes at CDF
Rick Field – Florida/CDF/CMS
Presentation transcript:

A.M. Baldin seminar series

XXI Baldin Seminar Retrospective A few historical remarks by Lee Pondrom

Dubna International Seminars on problems in high energy physics The first seminar was held in 1969, and about every two years since then. My first visit to Dubna was in 1970, at the Instrumentation Conference following the ‘Rochester’ conference in Kiev. The early conferences had simultaneous Rus-Eng translators. In 1988 the conference remained bilingual, but by 1998 it had switched to English.

Dubna International Seminars Professor Baldin was an organizer of the conference for many years. He was also a mountain climber. Field theory and its product QCD have been central themes of the seminars. Heavy ions and QCD plasma have been important subjects recently

A few personal recollections I gave a number of experimental reports over the years, starting with the Fermilab fixed target hyperon beams and continuing with Fermilab CDF collider work. The seminars are a good place to meet people. Frankfurt and Strikman, Gerasimov, Shirkov, Neudachin, Baldin, Pontecorvo, et al. I look forward to an interesting week, and I wish the organizers good fortune in continuing the series.

Search for double parton interactions in Z->  events from p-p collisions at 1.96 TeV Lee Pondrom, U. of Wisconsin, for the CDF Collaboration XXI International Baldin Seminar September 10-15, 2012

Old Moscow-Kitai Gorod in the 17 th century

Parts of CDF for this analysis Charged particle central tracker Central electromagnetic and hadronic calorimetry Central muon detectors Polar coordinates; origin at center of the detector, z axis in proton direction,  =- log(tan(  /2)), φ in plane perpendicular to the z axis.

CDF RunII dijet end view

Typical dijet event display

The parton model is indispensable for understanding hadron collisions Monte Carlo programs like Pythia base their analysis on the parton model, and are very successful in explaining observations. Pbar-p interactions are described by 2->2 simple parton-parton scattering, folded into parton distribution functions determined by lepton-hadron scattering.

In a double parton interaction this process occurs twice

Signature of DPI The two hard scatters are perturbative. The two hard scatters are independent, consistent with the conservation laws. If the momentum fractions and energies involved in the two scatters are modest, independence should be obtained. Two hard scatters in a single interaction can be modeled by two separate interactions (vertices) in the same event.

Single hard scatter and the ‘underlying event’

Single vertex dijet or Z+jet event

Charged tracks in the transverse region CDF studied the underlying event in the region transverse to Z production. PYTHIA was tuned to match the charged track distribution.(PRD82,034001,2010)). Track p T >.5 GeV, track |η|<1 Parameters track multiplicity, scalar sum track p T, max p T. The PYTHIA tune has been widely used.

Quick check of underlying event with dijet data

Transverse track activity depends slowly on p TZ or jet1 E T About 90% of the ∑p T plots are energy independent. PYTHIA agrees with data. Underlying event activity is the same for p TZ ≈ jet1E T If double parton interactions exist, a good place to look for them would be in the transverse region.

This suggests a new technique to look for DPI Look in the transverse region in φ, where the main event is relatively quiet. Use the high pt transverse tracks as a ‘trigger’ signature of a second hard interaction. Impose the arbitrary requirement ∑transtrackp T >15 GeV/c as the trigger

look at jet events with two vertices to test the idea Use dijet E T >100 GeV data Require jets one and two to be on the first vertex. Exactly two vertices per event. Extra jets three and four can be anywhere Separate the two vertices by at least 10 cm. Require vtx2 to have at least 3 charged tracks, with p T >.5 GeV and |η|<1. Second vtx σ ≈ 12 mb, called ‘minbias’.

Two vertex event with 2 jets on primary vtx and 2 jets on 2 nd vtx

Transverse tracks on the 2 nd vtx Minbias

Transverse track activity The first vertex transverse tracks are defined with respect to the azimuth φ of the highest E T jet:  /3<Δφ(jet-track)<2  /3 second vertex transverse tracks are defined in the same way with respect to the same jet – highest E T jet on vtx1, track on vtx2. ~60% of all ‘triggers’ have a pair of transverse jets with E T >5 GeV on 2 nd vtx.

∑transtrackp T >15 GeV Note that the fraction increases from.001 to.015 going from minbias (plotted as E T =5GeV) to jet E T >20 GeV Using σ ≈ 12 mb for the 2 nd vertex, the effective cross section for the ∑p T >15 GeV ‘trigger’ is σ ≈ 12  b.

Recoil jet E T against E T >20 GeV compared to 2 nd vtx jets

Δφ for 2 nd vtx jets relative to jet1 on 1 st vtx CDF Preliminary

2 nd vtx ‘trigger’ jets The ∑transtrackp T >15GeV ‘trigger’ creates two jets on the second vertex which are softer than jet20 (the lowest E T CDF jet trigger). The two jets created by the trigger are in the transverse region in φ relative to jet1, which is on the first vertex.

Δφ of jet pair on 2 nd vtx created by ∑transtrackp T >15 GeV/c

Δφ for jet pair on 2 nd vtx There is a clear back-to-back signal for the jet pair created in the transverse region in φ of the leading jet pair on the first vertex. The Δφ resolution is broader than for jetE T >20 Gev, which has on average higher E T jets.

DPI search strategy Use Z->  data to define the φ region transverse to p TZ. Require only one vertex in the event Apply the ∑transtrackp T >15 GeV ‘trigger’ Look for a pair of back to back jets like those found on the second vertex.

Use entire  Ldt=9/fb high p T muon dataset Require two muons opposite charge |η|<1. Eliminate events with cosmic rays Require at least one good quality central muon events 30GeV<m  <130GeV events 80GeV<m  <100 GeV Require at least one jet with E T >5 GeV events Z pair p T >10 GeV events Z pair p T >20 GeV

Z->  kinematics data and Pythia CDF Preliminary

E T jets 1&2 data and Pythia

E T jet3 and Δφ jet1-p TZ

Δφ jets-p TZ

Δφ p TZ and recoil jets Jet1 has a strong peak near Δφ≈ , but also has a long flat tail. Jets2 and 3 have a slight preference to be close to the p TZ vector direction! All three jets can occupy the transverse region. Pythia agrees with data regarding these features.

Drell-Yan mechanism and p TZ

Lowest order diagram has p TZ =0. Initial state radiation by either incident quark can give low p TZ, but soft multijets can cancel each other out. There are several variations of the Compton diagram, which dominate at higher p TZ.. Extra jets can radiate from anywhere..

∑transtrackp T for p TZ >10GeV

‘Trigger’=∑transtrackp T >15GeV/c. 3 jets required with E T >5GeV

Δφ jets p TZ data and Pythia

∑transtrackp T >15 GeV Jet E T distributions are broader after the ‘trigger’, the opposite of DPI expectations. Jets 1 and 2 both move into the transverse region in φ! This is not supposed to happen in double parton scattering. Jet 1 stays put to balance the Z.

∑transtrackp T >15 GeV The ‘trigger’ has little effect on jet3. The ‘trigger’ moves both jets 1&2 into the transverse φ region relative to p TZ. Δφ12 then favors ~140 degrees, forming a Mercedes Benz pattern in φ: p TZ -E Tj1 -E Tj2 Jet3 can be anywhere.

Jets 1 and 2 combine to balance p TZ,, jet 3 is anywhere

Δφ12 data and Pythia

Δφ23 data and Pythia

Δφ jet3 p TZ data and Pythia

Search for DPI in recoil jets 2&3

Effect of the trigger on jets 2&3 Pythia agrees with data regarding the behavior of jet3, given limited statistics. The true shape of Δφ23 without DPI is unknown. DPI should enhance Δφ23 near  radians No enhancement is observed.

Expected DPI yield Assume that each Z production event contains a DPI vertex as defined by the two vertex study. Then.0006 of all Z production events should have two extra back to back jets. Given 46,000 events implies 28 DPI events on the Δφ jets2&3 plot.

Expected DPI yield

Outlook Pythia and Z + jets data agree very well. Data show no sign of DPI. Z production is a clean environment- minimal color flow, no jets along p TZ, although there is jet activity ‘transverse’. The new technique of ∑transtrackp T >15GeV/c, which gives dijets on a 2 nd vertex, simply rearranges the kinimatics of the Z production.

Дополнительный материал Конец доклада

CDF detector

CDF RunII dijet end view

‘Trigger’=∑transtrackp T >15 GeV/c

The parton model is indispensable for understanding hadron collisions

‘Trigger’=∑transtrackp T >15 GeV/c

Second vertex is ‘minbias’ CDF ‘minbias’ σ ≈ 36 mb defined by the luminosity monitor Track requirements here are different, and σ ≈ 12 mb is smaller. In the data the avge probability of two vertices is 30%.