1 the structure of the nucleon 3 decades of investigation 1973-2004 - a personal perspective arie...

1

The Structure of the Nucleon3 decades of investigation

1973-2004 - a personal perspectiveArie Bodek, University of RochesterMadison, Wisconsin - Sept. 8, 2004

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• Particle Physics pre -1968 simplistic viewMany different models for Hadron Structure.Quarks was considered more of a convenient way to model a

symmetry rather than real particles (since none were ever observed and they had strange properties like 1/3 charge.

“Real Particle Physics” done in hadron (proton) machines where “Resonances” and new particles were being studied and discovered (spectroscopy, group theory, partial wave analysis, resonances, Regge poles etc.

•Short Interlude – quarks “discovered” in electron scattering

•Particle Physics post 1973 simplistic view•J/psi-Charm and then Upsilon-Bottom discovered e+e-, p-p•“Real Particle Physics now done at e+e- or hadron machine where new charm and bottom mesons and hadrons are discovered and studied, but now they are made of quarks (spectroscopy, partial wave analysis, resonances etc.).

•Particle Physics Now simplistic view - “Real Particle Physics done at e+e- or hadron machine where new particles are NOT discovered

(Supersymmetry, Lepto-quarks, Higgs, Heavy Leptons etc.

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The Structure of the Nucleon3 decades of investigation1973-2004a personal perspective

In the beginning there was hadron Spectroscopy and quarks were only mathematical objects

and then came the MIT-SLAC

electron scattering

experiments 1967-1973

And Quarks became Real Particles

by 2000: Nucleon Structure is well understood and NNLO QCD works from Q2=1 GeV2 to the highest values currently accessible in hadron colliders. How did we get there?

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Like the majority of advances in High Energy Physics, progress in this area was accomplished by:

1. Higher Energies (new accelerators and machines)

And more importantly in combination with2. New experimental techniques - Higher

Precision To go beyond the Limitations/Brick Walls of old techniques

3. Better understanding (new theoretical tools)4. Higher Luminosities (more statistics)5. Different probes (new beams)

by 2000: Nucleon Structure is well understood and NNLO QCD works from Q2=1 GeV2 to the highest values currently accessible in hadron colliders. How did we get there?

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If you want to be fussy, there are also a few photons from the electromagnetic interaction

Quarks (Fermions) - close to massless (MeV range)

Gluons (bosons) =field particles of the color force

1 GeV

Mass

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Inclusive Inclusive e + p e + X scattering scattering

Alternatively:

)(' LT

dEd

d εσσσ+Γ=

Ω

onpolarizati allongitudin relative : å

photons virtualpolarizedely transversofflux :ΓWhere

)/)2/(tan2/( 212'

MFFdEd

dmott θνσσ

+=Ω

12xF

FR L

T

L ==σσ

F

)2/(sin4

)2/(cos42

22

θθασ

Emott= 122

22

2)4

1( xFFQ

xMFL −+=

Quarks are spin 1/2

Virtual photons are spin 1 and have mass =q2.

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Inclusive Inclusive e + p e + X scattering scattering Single Photon Exchange

Elastic Resonance DIS

Alternatively:

)(' LT

dEd

d εσσσ+Γ=

Ω onpolarizati allongitudin relative : å

photons virtualpolarizedely transversofflux :Γ

Where

)/)2/(tan2/( 212'

MFFdEd

dmott θνσσ

+=Ω

12xF

FR L

T

L ==σσ

F

)2/(sin4

)2/(cos42

22

θθασ

Emott= 122

22

2)4

1( xFFQ

xMFL −+=

At high Q2 -> FL = 0 for spin 1/2 partons (virtual photon has spin 1, leading to a spin helicity flip)

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Prelude: SLAC MIT 1968-1974

Why do theorists like this experiment so much? - Victor Weisskopf

Because they can understand the experimental setup- it is one of the few experiment where the apparatus and Feyman diagram look the same

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MIT SLAC e-p DATA 1970 e.g. E0 = 4.5 and 6.5 GeV

e-P scattering A. Bodek PhD thesis 1972 [ PRD 20, 1471(1979) ] Proton Data

Electron Energy = 4.5, 6.5 GeV Data

V. Weisskopf * (former faculty member at Rochester and at MIT when he showed these data at an MIT Colloquium in 1971 (* died April 2002 at age 93) Said

What doThe Frank Hertz” and “Rutherford Experiment” of the proton’ have in common?

‘The Deep Inelastic Region is the “Rutherford Experiment” of the proton.

The electron scattering data in the Resonance Region is the “Frank Hertz Experiment” of the Proton.

A: Quarks! And QCD

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•A: Nobel Prize 1990 - Friedman, Kendall, Taylor for their pioneering investigations concerning deep inelastic scattering of electrons on protons and bound neutrons, which have been of essential importance for the development of the quark model in particle physics.” (1967-73)

Front row: Richard Taylor, Jerome Friedman, Henry Kendall.

Second row: Arie Bodek, David Coward, Michael Riordan, Elliott Bloom, James Bjorken, Roger (Les)

Cottrell, Martin Breidenbach, Gutherie Miller, Jurgen Drees, W.K.H. (Pief) Panofsky, Luke Mo, William

Atwood. Not pictured: Herbert (Hobey) DeStaebler Graduate students in italics

Described in detail in"The Hunting of the Quark," (Simon &

Schuster) Michael Riordan

AIP Science Writing Award 1988 & AIP Andrew Gemant Award 2003

Important to share the excitement of science with the public

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N =d d u + sea 1/3 1/3 2/3P = u u d + sea 2/3 2/3 1/3

Large x N/P -> 0.25 Explained by valence d/u PARTONS ARE QUARKS ! [ (1/3) / (2/3)]2 =1/4 Small x : N/P=1 explained by sea quarks

F2P

F2N

F2P

xx

1/4

2/3

Scaling-> Point like PARTONS

1968 - SLAC e-p scaling ==> Point like Partons in the nucleon 1970-74 - Neutron/Proton ratio - Partons are fractionally charged

(quarks)•COMPARISONS OF DEEP INELASTIC ep AND en CROSS-SECTIONS AB et al Phys. Rev. Lett. 30: 1087,1973. (SLAC Exp. E49 PhD thesis)-First result Next Step higher precision• THE RATIO OF DEEP - INELASTIC en TO ep CROSS-SECTIONSINTHE THRESHOLD REGION AB et al Phys.Lett.B51:417,1974 ( SLAC E87) PRL referees - nothing substantially new over 1973

1

2

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RP

R=σL/ σ T (small)

quarks are spin 1/2 !

EXTRACTION OF R = σL/σT FROM DEEP INELASTIC eP AND eD CROSS-SECTIONS. E. Riordan, AB et

al Phys.Rev.Lett.33:561,1974.

EXPERIMENTAL STUDIES OF THE NEUTRON AND PROTONELECTROMAGNETIC STRUCTURE FUNCTIONS. AB et al Phys.Rev.D20:1471-1552,1979.

BUT what is the x and Q2 Dependence of R?What is x, Q2 dependence of u, d, s, c quarks and antiquarks?

3

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4. Integral of F2(x) =0.5 did not add up to 1.0. Missing momentum attributed to “gluons”. Like Pauli’s missing energy in beta decay attributed to neutrinos*Gluons were “Discovered” in 1970, much before PETRA

BUT what is their x Distributions?

F2P

F2N

F2D

4

5

5. Scatter shows F2(x, Q2) as expected from bremstrahlung of gluons by struck quarks in initial of final states. BUT QCD NOT FULLY FORMALIZED YET

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QCD scaling violations from gluon emission are logarithmic with Q2

Scaling violations from quark binding effects (Higher Twist, Target mass) go like powers in 1/Q2

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• Next Higher Precision: First observation of Scaling Violations SLAC

• E. M. Riordan, AB et al TESTS OF SCALING OF THE PROTON ELECTROMAGNETIC STRUCTURE FUNCTIONS Phys.Lett.B52:249,1974 (more detail in AB et al Phys.Rev.D20:1471-1552,1979

Note in 2000. We show that Higher Twist come from Target Mass + NNLO QCD STUDIES OF HIGHER TWIST AND HIGHER ORDER EFFECTS IN NLO AND NNLO QCD ANALYSIS AB, UK Yang. Eur. Phys. J. C13 (2000) 241 245.

F2P Extracted

from Rosenbluth

separations

Scaling violations SEEN in 1974, Are they deviations from Parton Model e.g. from “gluon” emission, or are they just at Low Q2

1974: PRL Referees - obviously these are uninteresting low Q2 effects

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"Physics is generally paced by technology and not by the physical laws. We always seem to ask more questions than we have tools to answer. Wolfgang K. H. Panofsky•Questions in 1972-2000 Anti-quarks, strange , charm quarks in nucleons , individual PDFs (u,d,qbar,gluons Q2,x dependence) R= longitudinal structure function (x,Q2), quarks in nuclei , origin of scaling violations- low Q2 higher twist or QCD?,

•A Detailed understanding of Nucleon Structure Required Initiating Measurements at Different Laboratories, New Detectors, New Analysis Techniques and Theoretical Tools - AND also sorting out which experiments are right and which experiments are wrong - incremental but steady progress.

Meanwhile: the J/Psi was discovered in 1974 ---> and the age of Spectroscopy returned; and then came the Upsilon and there was more spectroscopy to be done. - but a few people continued to study the nucleon.

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How are Parton Distributions (PDFs) Extract from various data at large momentum transfer (e//ν and other expts.)

d/u

PDF(x)=

Valence and sea

Also Drell Yan, jets etc

H and D

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Also thanks to our Collaborators over the past 3.5 decades +FUTURE ( Blue awarded Panofsky Prize)

The Electron Scattering SLAC-MIT collaboration at SLAC End Station A (E49, E87) with Kendall, Friedman, Taylor, Coward, Breidenbach, Riordan, Elias, Atwood& others (1967-1973)

•The Electron Scattering E139, E140, E140x, NE8 collaboration at SLAC ESA/ NPAS injector at SLAC (with Rock, Arnold, Bosted, Phillipone, Giokaris & others) (1983-1993)

•The E379/E595 Hadronic Charm: with Barish, Wojcicki, Merrit. Fisk, Shaevitz& others) Production collaboration at Fermilab lab E (1974-83)

•The AMY e+e- Collaboration at TRISTAN/KEK (with Steve Olsen& others) (1982-1990)•The CCFR(W)-NuTeV Neutrino Collaboration at Fermilab Lab E (with (1974-2004) Barish, Sciulli, Shaevitz, Fisk, Smith,Merritt, Bernstein, McFarland and others)

•The CDF proton-antiproton Collaboration at Fermilab (1988-•And in particular I thank the graduate students and 2004) postdocs over the years, and Rochester Senior Scientists Budd, deBarbaro Sakumoto.+more progress to be made with collaborators at the CMS-LHC experiment,(1995-->)

The New Electron Scattering JUPITER Collaboration at

Jefferson Lab,& the new MINERvA Neutrino (1993-->

Collaboration at Fermilab (McFarland, Morfin, Keppel, Manly),

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Conclusion

Fermilab

CCFR/NuTeV v-N Expt.

-N (data)CDF Collider Expt

MINERvA Expt

J-lab

e-N (Data)

JUPITER Expt.

SLAC ESA SLAC NPAS programs

e-N Data

KEK

AMY @ TRISTAN

JHF

CERN -N, v-N (data)

CMS Collider

Rochester

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Caltech (->Columbia)- Chicago - Fermilab - Rochester -(Wisconsin) •The CCFR(W)-NuTeV Neutrino Collaboration at Fermilab Lab E (1974-2004) - separate quark and antiquark distributions, Valence and Sea• Barish, Sciulli, Shaevitz, Fisk, Smith,Merritt, Bernstein, McFarland and others)

. Budd, deBarbaro

Sakumoto

Rochester Senior Scientists









V-A Weak Interaction => difference between quarks and anti-quarks (Neutrinos are left handed and antineutrinos right handed)

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Neutrino physics is information rich

NC- Electroweak

CC- quarks antiquarks, PDFs and QCD

dimuons- Charm and Strange quarks

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Neutrino Experiments REQUIRE good Hadron Calorimetry and Muon Energy calibration (~0.3%) 10 cm Fe Sampling, NuTeV simultaneous neutrino running and hadron and muon test beamsD.A. Harris (Rochester), J. Yu et alNuTeV PRECISION CALIBRATION OF THE NUTEV CALORIMETER. UR-1561 Nucl. Inst. Meth. A447 (2000)W.K. Sakumoto (Rochester), et al. CCFR CALIBRATION OF THE CCFR TARGET CALORIMETER.Nucl.Instrum.Meth.A294:179-192,1990.CCFR Developed Fe-scintillator compensating calorimeter. 3mx3m large counters with wavelength shifting readout



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. CCFR(W) Neutrino detector used as a final state muon identifier in a high energy proton beam - what is the origin of prompt muon productxion in hadronic collision P+N-> D--> Muon 30% and P+N - > Dimuons 70%

B: Hadronic Charm Production - Lab E Fermilab E379/E595

Single muons from charm, dimuons from Drell-Yan, vary target density to determine rate of muons from pion decays (1974-1983)

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B: Hadronic Charm Production -Lab E Fermilab E379/E595 Single muons from charm, dimuons from Drell-Yan, vary target density to determine rate of muons from pion decays (1974-1983

Jack L. Ritchie, HADRONIC CHARM PRODUCTION BY PROTONS AND PIONS ON IRON. UR-861 (1983) Ph.D. Thesis (Rochester). Dexter Prize, U of Rochester - Now Professor at UT Austin

Hadronic Charm Production is about 20 mb. Distribution is peaked at small Feynman x and is dominated by quark-quark and gluon-gluon processes. No Intrinsic Charm quarks in the nucleon - in contradiction with ISR results.

•Intrinsic C(x) = 0

B: Are there charm quarks in nucleon ?

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C: Strange Quarks in the Nucleon - Caltech-Fermilab --> CCFR (Columbia -Chicago-Fermilab-Rochester) and -Later- NuTeV Neutrino Collaborations at Fermilab LAB E.

Dimuon event

Karol Lang, AN EXPERIMENTAL STUDY OFDIMUONS PRODUCED IN HIGH-ENERGY NEUTRINO INTERACTIONS. UR-908 (1985) Ph.D. Thesis (Rochester) Now Professor at UT AustinMost recently M. Goncharov and D. Mason (NuTeV PhDs)

The Strange Sea Anti-quarks are about 1/2 of the average of u and d sea - i.e Not

SU3 Symmetric.

K

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H. Kim (CCFR Columbia PhD); D.Harris (Rochester) et. al. MEASUREMENT OF αS (Q2) FROM THE GROSS- LLEWELLYN SMITH SUM RULE. Phys. Rev. Lett. 81, 3595 (1998)

W.G. Seligman et al. (CCFR Columbia PhD), IMPROVED DETERMINATION OF αS FROM NEUTRINO NUCLEON SCATTERING. Phys. Rev. Lett. 79 1213 (1997)

Precision High Statistics Neutrino Experiments at Fermilab - Valence, Sea, Scaling Violations, gluons F2 xF3 , Precise

αs GLS sum rule (Q2 dependence)

GLS( q2) dependence αs

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Precision Neutrino ExperimentsCCFR/NuTeVUn Ki Yang UR-1583,2000 Ph.D. Thesis, (Rochester) Lobkowicz Prize, U of R; URA Best Thesis Award Fermilab 2001 (now at Univ. of Chicago)Un-Ki Yang et al.. MEASUREMENTS

OF F2 AND XF3 FROM CCFR ν-FE DATA IN A PHYSICS MODEL INDEPENDENT WAY. By CCFR/NuTeV Phys.Rev.Lett.86, 2742,2001

Experiment vs Theory: Ratio of

F2 (neutrino)/F2 (muon)

Resolved 10% to 20% difference between ν and data

Same PDFs should describe all processes

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A lot of other physics (not related to nucleon structure) was investigated in the lab E E595 hadron program and the Lab E

CCFR (W) /NuTeV Neutrino Program --- a few examples:

Some discoveries and precise measurements e.g. • Neutral Currents and electroweak mixing angle, Trimuons

(CCFR(w)/NuTeV)And also searches and limits (A few non-discoveries)• Limits on Dzero to Dzero-bar mixing (E595)• Search for New Heavy Leptons – Pawel de Barbaro,

Rochester PhD Thesis 1990• Search for inclusive oscillations of muon neutrinos - Ian

Stockdale, Rochester PhD Thesis 1984• Search for exclusive oscillations of muon neutrinos to

electron neutrinos – Sergei Avvakumov, Rochester PhD Thesis 2002

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D Quark Distributions in Nuclei - New Parallel Program at SLAC

AB, J Ritchie FERMI MOTION EFFECTS IN DEEP INELASTIC LEPTON SCATTERING FROM NUCLEAR TARGETS, Phys.Rev.D23:1070,1981; Phys.Rev.D24:1400,1981.

1983 (conference proceeding) surprising report of difference between Iron and Deuterium muon scattering data from the European Muon Collaboration (EMC) Disagreement with Fermi Motion Models.

ELECTRON SCATTERING FROM NUCLEAR TARGETS AND QUARK DISTRIBUTIONS IN NUCLEI. AB et al Phys.Rev.Lett.50:1431,1983.. - Use Empty Target Data from SLAC E87 (1972)(initially rejected by Phys. Rev, Letters) IRONA COMPARISON OF THE DEEP INELASTIC STRUCTURE FUNCTIONS OF DEUTERIUM AND ALUMINUM NUCLEI. AB et al Phys.Rev.Lett.51:534,1983. Use empty target data from SLAC E49B (1970) ALUMINUM

AB, EMPTY TARGET SUBTRACTIONS AND RADIATIVE CORRECTIONS IN ELECTRON SCATTERING EXPERIMENTS, Nucl. Inst. Meth. 109 (1973). - factor of 6 increase in rate of empty target data by making empty target same radiation length as H2 and D2 targets; - used in SLAC E87 - more payoff later

Physics Archeology - Use 12 and 13 year old SLAC Empty target data to check on this

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Quark Distributions in Nuclei AB et al Phys. Rev. Lett. 51: 534, 1983 (SLAC Expt. E49, E87 empty tgt data 1970,1972)

EMC

PRL Referees: (1) How can they claim that there are quarks in nuclei + (2) Obviously uninteresting multiple scattering of electrons in a nucleus- --> later accepted by PRL editors.

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D. Back to SLAC using High Energy Beam and the Nuclear Physics Injector NPAS - SLAC E139, E140, E140x, E141, NE8

R.G. Arnold et al., MEASUREMENTS OF THE A-DEPENDENCE OF DEEP INELASTIC ELECTRON SCATTERING FROM NUCLEI Phys. Rev. Lett.52:727,1984; (initial results incorrect by 1% since two photon external radiative corrections for thick targets not initially accounted for. Found out later in SLAC E140)

J. Gomez et al., MEASUREMENT OF THE A-DEPENDENCE OF DEEP INELASTIC ELECTRON SCATTERING. Phys.Rev.D49:4348-4372,1994.

Back to SLAC End Station A to measure effect on various nuclei

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1983: The field of quark distributions in nuclei hit a brick wall: The issues:

(1) Precise Values and Kinematic dependence of R needed to extract F2 from all electron muon and neutrino experiments.

(2) Precise normalization of F2 needed to establish normalization of PDFs for all DIS experiments to 1%. Solution-->SLAC E140 -

New hardware, new theoretical tools 1 month run worth years of data, IMPACT all DIS Experiments Past and Future.

(1) Upgrade Cerenkov Counter for ESA 8 GeV spectrometer - N2 with wavelength shifter on phototube

(2) Upgrade Shower Counter from lead-acrylic (to segmented lead glass)

(3) Upgraded tracking (wire chambers instead of scintillator-hodoscope)

(4) Upgraded Radiative Corrections - Improved treatment using Bardin, Complete Mo-Tsai, test with different r.l. targets ( to 0.5%)

(5) Cross normalize all previous SLAC experiment to SLAC E140 by taking data in overlap regions.(Re-analysis with upgraded rad corr).

SLAC E140, E140x - . New Precision Measurement of R and F2, and Re-Analysis of all SLAC DIS data to obtain 1% precision.

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Sridhara Rao Dasu, PRECISION MEASUREMENT OF X, Q2 AND A-DEPENDENCE OF R = σL/σT AND F2 IN DEEP INELASTIC SCATTERING. UR-1059 (Apr 1988) . Ph.D. Thesis. (Rochester) SLAC E140 - winner of the Dexter Prize U of Rochester 1988(now on the faculty at U. Wisconsin, Madison)

S. Dasu (Rochester PhD )et al., MEASUREMENT OF THE DIFFERENCE IN R = σL/σT, and σA/σD IN DEEP INELASTIC ed, eFE AND eAuSCATTERING. Phys.Rev.Lett.60:2591,1988;

S. Dasu et al., PRECISION MEASUREMENT OF R = σL/σT AND F2 IN DEEP INELASTIC ELECTRON SCATTERING. Phys.Rev.Lett.61:1061,1988;

S. Dasu et al., MEASUREMENT OF KINEMATIC AND NUCLEAR DEPENDENCE OF R =

σL/σT IN DEEP INELASTIC ELECTRON SCATTERING. Phys.Rev.D49:5641-5670,1994.

L.H. Tao (American U PhD) et al., PRECISION MEASUREMENT OF R = σL/σT ON HYDROGEN, DEUTERIUM AND BERYLLIUM TARGETS IN DEEP INELASTIC ELECTRON SCATTERING. Z.Phys.C70:387,1996 L.W. Whitlow (Stanford PhD), et al. , A PRECISE EXTRACTION OF R = σL/σT FROM A GLOBAL ANALYSIS OF THE SLAC DEEP INELASTIC ep AND ed SCATTERING CROSS-SECTIONS. Phys.Lett.B250:193-198,1990. L.W. Whitlow, et. al., PRECISE MEASUREMENTS OF THE PROTON AND DEUTERON STRUCTURE FUNCTIONS FROM A GLOBAL ANALYSIS OF THE SLAC DEEP INELASTIC ELECTRON SCATTERING CROSS-SECTIONS. Phys.Lett.B282:475-482,1992.

http://216.103.90.216/Family2003/Family2003-Pages/Image5.html

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Provided normalization and shape at lower Q2 for all DIS experiments- constrain systematic errors on high energy muon experiments - Perturbative QCD with and without target mass (TM) effects

35

Current Status of Unpolarised SFsCurrent Status of Unpolarised SFs

From Bodek (2000)

Overall, F2 is well measured over 4 orders of magnitude,

36

SLAC E140 and the combined SLAC re-analysis provided the first precise values and kinematic dependence of R

Related to F2/2xF1

for use by all DIS experiments to extract F2 from differential cross section data

R

37

Proton-Antiproton (CDF/Dzero) collisions are actually parton-parton collisions (free nucleons)

Measure W mass from Transverse mass of electrons from W decays W->electron-neutrino

38

Proton-Antiproton (CDF/Dzero) collisions are actually parton-parton collisions (free nucleons)

By introducing new techniques, CDF data can provide independent constraints on free nucleon PDFs.

CONSTRAINTS ON PDFS FROM W AND Z RAPIDITY DIST. AT CDF. AB, Nucl. Phys. B, Proc. Suppl. 79 (1999) 136-138. In *Zeuthen 1999, Deep inelastic scattering and QCD* 136-138.

In 1994 uncertainties in d/u from deuteron binding effects contributed to an uncertainty in the W mass (extracted from CDF or Dzero Data of order 75 MeV. ANOTHER BRICK Wall

This is why it is important to know the nuclear corrections for PDFs extracted from nucleons bound in Fe (neutrino) or in Deuterium (d versus u), when the PDFs are used to extract information from collider data

39

E: Proton-Antiproton (CDF/Dzero) collisions are actually parton-parton collisions (free nucleons)

40

Mark Dickson, THE CHARGE ASYMMETRY IN W BOSON DECAYS PRODUCED IN P ANTI-P COLLISIONS. (1994) Ph.D.Thesis (Rochester). (now at MIT Lincoln Labs)Qun Fan, A MEASUREMENT OF THE CHARGE ASYMMETRY IN W DECAYS PRODUCED IN P ANTI-P COLLISIONS. Ph.D.Thesis (Rochester 1996) (now at KLA-Tenor

Proton-antiproton collisions (CDF)-

Measurement of d/u in the proton by using the W+- Asymmetry

42

Need to measure the W Decay lepton Asymmetry at high rapidity where there is no central tracking

Unfortunately W’s decay to electrons and neutrinos - Decay lepton asymmetry is a convolution of the W production Asymmetry

43

A NEW TECHNIQUE FOR DETERMINING CHARGE AND MOMENTUM OF ELECTRONS AND POSITRONS USING CALORIMETRY AND SILICON TRACKING. AB and Q. Fan In *Frascati 1996, Calorimetry in HEP*553- 560 (First used in AMY)

Use silicon vertex detector to extrapolate electron track to the forward shower counters. Compare the extrapolated location to the centroid of the EM shower in a segmented shower counter.

Energy of electron determined by the shower counter, Sign is determined by investigating if the shower centeroid is to the left or right of the extrapolated track,

All hadron collider physics (Tevatron, LHC) with electrons and positrons can be done better without a central tracker . No Track mis-ID Need Just silicon tracking and segmented EM +HAD calorimetry -Adapted by CMS-LHC

44

The d/u ratio in standard PDFs found to be incorrect. Now all new PDF fits include CDF W Asymmetry as a constraint. PDF error on W mass reduced to 10 MeV by using current CDF data.

45

With this new technique, one can also significantly reduce the QCD background for very forward Z Bosons produced in hadron colliders.Jinbo Liu, Measurement of dσ /dy for Drell-Yan e+e Pairs in the Z Boson Region Produced in Proton Anti-proton Collisions at 1.8 TeV. UR-1606, 2000 - Ph.D. Thesis (Rochester). (now at Lucent Technologies) T. Affolder et al. (CDF- article on Rochester PhD Thesis), MEASUREMENT OF dσ / dY FOR HIGH MASS DRELL-YAN E+ E- PAIRS FROM P ANTI-P COLLISIONS AT 1.8-TEV. Phys.Rev.D63:011101,2001.

NLO QCD describes Z -y distributions better than LO QCD -> more statistics - Tevatron run II & LHC

46

Knowledge of high x PDF is used as input to searches for new Z’ bosons in high-mass Drell-Yan cross sections and Forward-Backward Asymmetry (another use of forward tracking of electrons)

Arie Bodek and Ulrich Baur IMPLICATIONS OF A 300-GEV/C TO 500-GEV/C Z-PRIME BOSON ON P ANTIP COLLIDER DATA AT 1.8-TEV. Eur.Phys.J.C21:607-611,2001 .

T. Affolder et al.(CDF) Measurement of dσ / dM and forward backward charge asymmetry for high mass Drell-Yan e+ e- pairs from p anti-p collisions at 1.8-TeV.

Phys.Rev.Lett.87:131802,2001

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Knowing level of PDFs at High x

Allows us to search for New Physics

In High Mass Drell Yan Events

Manoj Kumar Pillai, A SEARCH FOR NEW GAUGE BOSONS IN ANTI-P P COLLISIONS AT 1.8-TEV at CDF (1996). Ph.D.Thesis (Rochester)

Abe et al.,(CDF) LIMITS ON QUARK - LEPTON COMPOSITENESS SCALES FROM DILEPTONS PRODUCED IN 1.8-TEV P ANTI-P COLLISIONS. Phys.Rev.Lett.79:2198-2203,1997.

Abe et al. (CDF), MEASUREMENT OF Z0 AND DRELL-YAN PRODUCTION CROSS-SECTION USING DIMUONS IN ANTI-P P COLLISIONS AT 1.8-TEV. Phys.Rev.D59:052002,1999

Abe et al.(CDF)SEARCH FOR NEW GAUGE BOSONS DECAYING INTO DILEPTONS IN ANTI-P P COLLISIONS AT 1.8-TEV. Phys.Rev.Lett.79:2192-2197,1997

A few non-discoveries

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Expected CDF Run II 2 fm-1 Drell Yan Mass Distribution Need even better PDFs

Expected Z Rapidity 2 fm-1

CDF Rochester PhD Thesis (in progress) Ji Yeon Han

Expected W Asymmetry 2 fm-1

CDF Rochester PhD Thesis (in progress)

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F: Phenomenology: PUTTING it ALL TOGETHER The Great Triumph of NNLO QCD Origin of Higher Twist Effects, d/u and PDFs at large X –

PARTON DISTRIBUTIONS, D/U, AND HIGHER TWIST EFFECTS AT HIGH X. AB, UK Yang Phys.Rev.Lett.82:2467-2470,1999 .

STUDIES OF HIGHER TWIST AND HIGHER ORDER EFFECTS IN NLO AND NNLO QCD ANALYSIS OF LEPTON NUCLEON SCATTERING DATA ON F(2) AND R = σ(L) / σ(T). AB, UK Yang Eur.Phys.J.C13:241-245,2000

NNLO QCD +target mass corrections describes all of DIS data for Q2>1 GeV2 with NO Need for Higher Twists. GREAT TRIUMPH for QCD . Most of what was called low Q2 higher Twist are accounted for by higher order QCD.

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NNLO QCD+TM black Great Triumph of NNLO QCD. AB, UK Yang Eur.Phys.J.C13:241-245,2000

Size of the higher twist effect with NNLO analysis is very small a2= -0.009 (in NNLO) versus –0.1( in NLO) - > factor of 10 smaller, a4 nonzero

NNLO QCD+Tgt Mass works very well for Q2>1 GeV2

F2P

F2D

R

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Precision experiment can be done in hadron colliders, provided we calculate processes higher orders QCD (e.g. NNLO)

Lots of work for experimentalists - precision experiments are possible in hadron colliders (look forward to new results from the LHC)

Lots of work for Theorists - Lots of calculations are needed in order to get physics out of the data

2000-2004->2010 (The high Energy Frontier): For Tevatron and Run II and LHC , the path to greater precision is using: NNLO QCD fits with both Q2>1 GeV2 DIS data & very high Q2 Collider Data.-Good for theorists

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Great Triumph of NNLO QCD. AB, UK Yang Eur.Phys.J .C13:24,2000 First extraction of (NNLO PDFs)/(NLO PDFs) ratio

For High Statistics Hardon Collider Physics (run II, LHC), the next step is to extract NNLO PDFs. So declare victory and let theorists and PDF Professionals (MRST and CTEQ) make progress towards the next generation NNLO PDF fits for Tevatron and LHC

High x NNLO PDFs 10% lower than NLO PDFs

Low x NNLO PDFs 2% higher than NLO PDFs

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F2, R comparison of NLO QCD+TM+HT black (Q2>1)(use QCD Renormalons for HT vs NLO QCD+TM only green AB, UK Yang Phys.Rev.Lett.82,1999 PDFs and QCD in NLO + TM + QCD Renormalon Model for Dynamic HT describe the F2

and R data very well, with only 2 parameters. Dynamic HT effects are there but small

NLO QCD + Target Mass + Renormalon HT works. A GREAT QCD TRIUMPH

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CONCLUSION: Progress is made in finite incremental steps as new techniques and methods lead to greater precision (making what was impossible -> possible)

A factor of 2 reduction in error each generation (either statistical or systematic) is worth it, and one can always go back and re-analyze old data with better corrections to reduce systematic errors

In 4 generations of experiments (2)4 = 16 fold reduction in statistical errors -reduce systematics with new techniques

2000: Nucleon Structure well understood. NNLO QCD works from Q2=1 to the highest values currently accessible. Hadron colliders are actually quark and gluon colliders with known and well understood PDFs.->

We now have the foundation for making discoveries (e.g. Higgs) at LHC

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Back to the past (and the future) NEUTRINO SECTOR•2000-2004->2010 (The Low Energy Frotier)•Neutrino Oscillations at Low Energy•2000-2004: Atmospheric and solar neutrino experiments now show evidence for neutrino oscillations (small masses and large mixing). An emerging new field.-> Leptogenesis as a source of Matter-Antimatter Asymmetry in the Universe?•However, since the masses are small, the neutrino oscillations effects can only be observed be at low neutrino energies. In addition, the studies require the use of nuclear targets (water, iron, carbon)--> Cry for help

In order to make any advances in this new field, we need to understand neutrino cross sections and Nucleon and Nuclear Structure down to Q2=0 - Need new foundation

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Neutrino Cross Sections at Low Energy

Quasi-Elastic / Elastic (W=M)– ν + n - + p Input from both electron and neutrino

experiments and described by form factors, need axial form factor and nuclear corrections

Resonance (low Q2, W< 2)

ν + p - + p +

Can be well measured in electron scattering, but poorly measured in neutrino scattering (fits by Rein and Seghal). Need R, axial form factors and nuclear corrections

Deep Inelastic (DIS)– ν + A - + X well measured in high energy experiments

and well described by quark-parton model, but doesn’t work well at low Q2. Need low Q2 structure functions, R, axial structure funct. and nuclear corrections

Resonance scattering and low Q2 DIS contribution meet, (How to avoid double counting ?).

Challenge: to describe all these three processes at all neutrino (and electron/muon) energies. See if model satisfies all known sum rules from Q2=0 to very high Q2

(Need to understand duality, QCD, low Q2 sum rules, transition between DIS and resonance)

Issues at few GeV

σT/E ν

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For Tevatron Run II and LHC, the path to greater precision is to perform NNLO QCD fits using both Q2>1 GeV2 DIS data and very high Q2 Tevatron and LHC results.

In contrast, for applications to Neutrino Oscillations at Low Energy (down to Q2=0) the best approach is to use a LO PDF analysis (including a more sophisticated target mass analysis) and include the missing QCD higher order terms in the form of Empirical Higher Twist Corrections.Reason:

For Q2>1 both Current Algebra exact sum rules (e.g. Adler sum rule) and QCD sum rules (e.g. momentum sum rule) are satisfied. This is why duality works in the resonance region (so use NNLO QCD analysis)

For Q2<1, QCD corrections diverge, and all QCD sum rules (e.g momentum sum rule) break down, and duality breaks down in the resonance region. In contrast, Current Algebra Sum rules e,g, Adle sum rule which is related to the Number of (U minus D) Valence quarks) are valid.

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Original approach (NNLO QCD+TM) was to explain the non-perturbative QCD effects at low Q2, but now we reverse the approach: Use LO PDFs and “effective target mass and final state masses” to account for initial target mass, final target mass, and missing higher orders

Modified LO = Pseudo NNLO approach for low energies

Applications to Jlab and Neutrino Oscillations

P=M

q

mf=M*(final state interaction)

Resonance, higher twist, and TM

w=Q2+mf

2 +A

Mν (1+(1+Q2/ν2) )1/2 +BXbj= Q2 /2 Mν

K factor to PDF, Q2/[Q2+C]

A : initial binding/target mass effect

plus higher order terms

B: final state mass mf2 , mand photo-

production limit (Q2 =0)

MODELING DEEP INELASTIC CROSS-SECTIONS IN THE FEW GEV REGION. AB, UK Yang Nucl.Phys.Proc.Suppl.112:70,2002

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Describes all vector structure functions from Q2=0 to 100,000 GeV2

http://web.pas.rochester.edu/~icpark/MINERvA/fig/fig_lxc1h1d1_xb12_0.eps

http://web.pas.rochester.edu/~icpark/MINERvA/fig/fig_lxc1h1d1_xb12_1.eps

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MODELING DEEP INELASTIC CROSS-SECTIONS IN THE FEW GEV REGION. A. Bodek , U.K. Yang Presented at 1st Workshop on Neutrino - Nucleus Interactions in the Few GeV Region (NuInt01), Tsukuba, Japan, 13-16 Dec 2001. Nucl.Phys.Proc.Suppl.112:70-76,2002 e: hep-ex/0203009

HIGHER TWIST, XI(OMEGA) SCALING, AND EFFECTIVE LO PDFS FOR LEPTON SCATTERING IN THE FEW GEV REGION. A Bodek, U.K. Yang Proceedings of 4th International NuFact '02 Workshop (Neutrino Factories Workshop on Neutrino Factories, London, England, 1-6 Jul 2002. J.Phys.G29:1899-1906,2003

MODELING NEUTRINO AND ELECTRON SCATTERING INELASTIC CROSS- SECTIONS IN THE FEW GEV REGION WITH EFFECTIVE LO PDFS IN LEADING ORDER. A. Bodek, U.K. Yang . 2nd International Workshop on Neutrino - Nucleus Interactions in the Few GeV Region (NUINT 02), Irvine, California, 12-15 Dec 2002. Nucl.Phys.Proc.Suppl. hep-ex/0308007

Invited Article to be published in Annual Review of Particle and Nuclear Science 2005

Applications to Neutrino Oscillations at Low Energy

61

http://web.pas.rochester.edu/~icpark/MINERvA/fig/fig_lxc1h1d1_photo_0.eps

http://web.pas.rochester.edu/~icpark/MINERvA/fig/fig_lxc1h1d1_photo_1.eps

http://web.pas.rochester.edu/~icpark/MINERvA/h1/fig_H1_v4_comp.eps

http://web.pas.rochester.edu/~icpark/MINERvA/h1/fig_H1_v4_ratio.eps

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http://web.pas.rochester.edu/~icpark/MINERvA/fig/fig_lxc1h1d1_reso_0.eps

http://web.pas.rochester.edu/~icpark/MINERvA/fig/fig_lxc1h1d1_reso_1.eps

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http://web.pas.rochester.edu/~icpark/MINERvA/nmc/fig_NMC_v4_comp_1.eps

http://web.pas.rochester.edu/~icpark/MINERvA/nmc/fig_NMC_v4_comp_0.eps

http://web.pas.rochester.edu/~icpark/MINERvA/nmc/fig_NMC_v4_ratio_1.eps

http://web.pas.rochester.edu/~icpark/MINERvA/nmc/fig_NMC_v4_ratio_0.eps

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•2000-2004->2010 (The Low Energy Frotier)•* Vector Part well understood - Phenomenology AB+U K Yang (2002-2004)•However, need more data on F2 and R in the resonance region for both axial and vector scattering• 2004-2005 (JUPITER, e-N at Jlab) - Collaborative effort between HEP and Nuclear Physics communities - Approved January 2004

•- Axial Structure Function also need to be measured in the next Generation NUMI Neutrino beam - •2005-2008 MINERvA, v-N at Fermilab)- Also Collaborative effort between HEP and Nuclear Physics communities - Approved March 2004.

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G: JUPITER at Jlab (Bodek - Rochester,Keppe- Hampton, Spokespersons) will provided electron-Carbon (also e-H and e-D and other nuclei such as e-Fe) data in resonance region, and final states (Manly-Rochester)-summer 05. & MINERvA at FNAL (McFarland=Rochester, Morfin -Fermilab) will provide Neutrino-Carbon data at low energies. Needed in order to investigate the electroweak sector at low mass (neutrino oscillations)

G: CDF Run II (now) and CMS-LHC, high statistics W’s Z’s and Drell Yan - Precise PDFs to investigate the electroweak sector at high mass (Top, Higgs)

Maintaining the colorful QCD Program

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Additional Slides

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Time Line Several Parallel Program over 30 years

Electron scattering e-P, e-N, e-A * (Kendal Friedman Taylor- Panofsky & Nobel Prizes)

•Electron Scatt. SLAC-MIT SLAC E49, E87+more(1967-1973) A --------- D

•Electron Scatt. SLAC E139, E140, E140x,E141, NE8 (1983-1993) D

•New Electron Scatt. JUPITER Expt at Jefferson Lab (2004-now G)

Hadron Expt. p-Fe, pion-Fe and p-pbar, p-p colliders *

•E379/E595 Hadronic Charm Production at Fermilab (1974-1983) B

•CDF proton-antiproton Expt at Fermilab (1988---E----now) {Develop segmented tile-fiber and strip-fiber calorimetry ( 1990------2004)•CMS Experiment at CERN LHC (1995-----now)Neutrino Experiments * (Frank Sciulli Panofsky Prize)

•The CCFR-NuTeV Neutrino Expt at Fermilab (1974------- C-------2004)

•New MINERvA Neutrino Expt at Fermilab (2004-now G)

Phenomenology *(1999-F-now)

e+e- Experiments•The AMY e+e- Collaboration at TRISTAN/KEK JAPAN (1982-1990) skip

A lot of fun, but mostly unrelated to nucleon structure – except measurement of αS

And Shower Electron tracking with with segmented calorimetry

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"Physics is generally paced by technology and not by the physical laws. We always seem to ask more questions than we have tools to answer.”

Wolfgang K. H. Panofsky2004 Arie Bodek (Rochester)

2003 William Willis (Columbia)

2002 Kajita Takaaki, Masatoshi Koshiba and Yoji Totsuka

2001 Paul Grannis (SUNY SB)

2000 Martin Breidenbach (SLAC)

1999 Edward H. Thorndike (Rochester)

1998 David Robert Nygren (Berkeley)

1997 Henning Schroder and Yuri Zaitsev

1996 Gail G. Hanson and Roy F. Schwitters

1995 Frank J. Sciulli (Columbia)

1994 Thomas J. Devlin (Rutgers)

and Lee G Pondrom (Wisconsin)

It is an honor to be

associated with these

previous Panofsky Prize Winners 1993 Robert B. Palmer, Nicholas P.

Samios, and Ralph P. Shutt

1992 Raymond Davis, Jr. and Frederick Reines

1991 Gerson Goldhaber and Francois Pierre

1990 Michael S. Witherell (Santa Barbara)

1989 Henry W. Kendall, Richard E. Taylor, and Jerome I. Friedman (MIT/SLAC)

1988 Charles Y. Prescott (SLAC)

1 the structure of the nucleon 3 decades of investigation 1973-2004 - a personal perspective arie...

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