lepton-hadron and hadron-hadron scatteringksmcf/cipanp/summary.pdfi. gialas diffraction at hera w....

Lepton-Hadron and Hadron-Hadron Scattering

CIPANP Summary of SessionCrack of Dawn, May 24, 2003

Volker BurkertAbhay Deshpande

Kevin McFarland

24 May 2003 CIPANP WG1 Summary: Burkert, Deshpande, McFarland

2

Purposes of & Prospects for LH-HHS

covered

lsewhere

! Studies of QCD"hadron structure"soft processes"dynamics & phenomena

! Neutrino detection"understanding of σLH

! Factory for, e.g.,"high mass states"quark-gluon plasma"exotic hadrons

! Precision studies at high rate facilities"“Medium-energy”

facilities, e.g., CEBAF"Future neutrino beams:

NUMI, J-PARC

! Future e-A colliders"ELIC, eRHIC, HERA 3

e


3






NUMI, J-PARC


hadron structureHard QCD

S. Boyd ν DIS and charm production (NuTeV)P. Reimer Drell-Yan Cross Section in pp and pdR. Yoshida HERA II Weak SF MeasurementsC. Mesropian Hard QCD at the TeVatronM. Tuts W/Z Production at the TeVatron


4

Hadron Structure: Particle Motivation

But how much glue is at high x?

!Searches for new physics relies on understanding how to produce it!

-25

0

25

50

75

100

125

150

% D

iffe

renc

e fr

om N

LO

QC

D w

ith

MR

SD0/

CDFMRSA/

CTEQ 2MCTEQ 2ML

10-6

10-4

10-2

1

10 2

10 4

10 5

0 100 200 300 400

CDFNLO QCD

1/∆

η ∫ d

2 σ/(

dETdη

) dη

nb/G

eVGeV-50

-25

0

25

50

75

100

125

150

% D

iffe

renc

e fr

om N

LO

QC

D w

ith

MR

SD0/

CDFMRSA/

MRSG

CTEQ 2MCTEQ 2MLGRV-94

0

20

0 50 100 150 200 250 300 350 400 450

Systematic uncertainties

10-6

10-4

10-2

1

10 2

10 4

10 5

0 100 200 300 400

CDFNLO QCD

1/∆

η ∫ d

2 σ/(

dETdη

) dη

nb/G

eV

GeV

! E.g., “Rutherford” at TeVatron (Liss)

GeV-50 MRSG GRV-94

0

20

0 50 100 150 200 250 300 350 400 450

Systematic uncertainties


5


6

Charm production

D. Mason (U. Oregon)

•A charm quark can be produced when a neutrino scatters off a s(d) quark in the nucleon.

•Independent probe of strange and anti-strange seas if different.

(Boyd)


7

Drell-Yan µ+µ- Production and PDF’s

• Possibly related to d/u ratio as x→1, but requires full PDF fit.

• Working with CTEQ to incorporate data in global fit.

• Radiative corrections under study.

(Reimer)


8

HERA I high-x measurementsare statistics limited

HERA II Physics Summary

HERA II projection

1 fb-1 of data # high statistics at high Q2 and Et.

Access to high-x partons at high Q2. Jets at high Et and Q2

#pQCD studies (PDF’s, jet cross-sections) at higher scales.Further improve understanding of QCD.


9

QCD at TeVatron(Mesropian, Tuts)


10






NUMI, J-PARC


hadron structure…beyond inclusive DISWG1/WG8 – Generalized Parton Distributions

A. Belitsky - GPD OverviewH. Avakian - Single Spin Asymmetries with CLASJ. Volmer - DVCS at HERMES/DESYE. Smith - DVCS with CLAS/Jefferson Lab


11

Generalized Parton Distributions

!What is a GPD?

Quark longitudinalmomentum & helicitydistributions

Proton form factors,transverse charge & current distributions

GPDs connect form factorsand parton distribution

(Belitsky)


12

GPDs Contain Much More Information than DIS

Quark distribution q(x)

qq distribution

Antiquark distribution q(x)DIS only measures a cut at ξ=0

Ji’s Spin Sum Rule


13

GPDs accessible in Deeply Virtual Exclusive & Semi-Inclusive Processes

Q2 = 2. - 2.5 GeV2x = 0.25 - 0.325

φ

γx+ξ x-ξ

t

CLAS@JLabDVCS on protons

HERMES@DESY DVCS on nuclei

DVCS

Azimuthal dependencedue to DVCS/BH inter-ference

DVCS

BH

(Volmer, Smith)


14

Single Spin Asymmetry for ep eπ+XFor factorizable processes, single-spin asymmetries are sensitive to various GPDs inaccesible in inclusive DIS.

qqLq

qqLUL HxheS

⊥⊥−

Σ∝ 1)1(

12

,

2sin )(φσ

)()( 12

,

sin zHxxheQMS qLq

qqLUL

⊥−

Σ∝φσ

)()( 112

,

sin zDxfeS qqTqqq

TUT⊥

−Σ∝φσ

)()( 112

,

sin zHxheS qqqq

TUT⊥

−Σ∝φσ

CLAS/JLab

CLAS/JLab

sin2φ moment is a cleansource of Collins SSA

φ

xB

(Avakian)


15




! Factory for, e.g.,"high mass states"quark-gluon plasma"exotic hadrons



NUMI, J-PARC


soft processesDiffractive QCD

K. Goulianos Diffraction at the TeVatronI. Gialas Diffraction at HERAW. Lorenzon Exclusive rho Production at HERMES


16

! Common fit at fixed lc yields positive slope of Q2-dependence ofnuclear transparency in nitrogen HERMES collab., PRL 90, 052501 (Feb 2003)⇒ signature of Color Transparency B.Z. Kopeliovich et al., PR C65, 035201 (2002)

0.0600.048

0.070 ± 0.021 ± 0.0120.089 ± 0.046 ± 0.008

coherentincoherent

PredictionMeasured Q2 slopeData sample

(Lorenzon)

Nuclear Transparency in Exclusive ρ0 Production at HERMES


17

Run II Diffraction at the Tevatron

ROMANPOTS

CDF

TOROID

MINIPLUG

z 56.40 m 31.63 m 23.23 m 6.59 m 0

BSC-4 BSC-3 BSC-2 BSC-1

QUADSDIPOLES

A - 4 8

ESS

ELE

CT

RO

ST

AT

ICS

EP

AR

AT

OR

$ MiniPlug calorimeters (3.5


18

Run II Dijets in Single Diffraction (CDF)

Agreement with Run INo Q2 dependence

R=(SD/∆ξ)/ND

ND+SD & SD+MBoverlap events

ξ ~ 1SD

events0.03


19

Run II: Exclusive DPE Dijets ?

No exclusive dijetbump observed

Generous upper limiton exclusive dijets

(Goulianos)

e

pIPIP

p

η

φ

Double PomeronExchange (DPE)


20

(Pitzl)


21






NUMI, J-PARC


dynamics and phenomenaC. Keppel Quark-Hadron Duality


22

Quark-Hadron Duality(Keppel)

! Duality between quark and hadron descriptions" reflects relationship between confinement and asymptotic

freedom" intimately related to nature and transition from non-

perturbative to perturbative QCD

24 May 2003

CIPANP WG1 Summary: Burkert, Deshpande,

McFarland23

Duality now observed in all unpolarizedstructure functions

2xF1 FL

(Keppel)


24




! Precision studies at high rate facilities"“Medium-energy” lepton


NUMI, J-PARC


understanding of σLHFuture neutrino beams“Medium enegy” leptonfacilities

A. Bodek Modeling Electron and NeutrinoCross-Sections at a few GeV

H. Gallagher Neutrino Cross-Section Generators

CIPANP WG1 Summary: Burkert, Deshpande, McFarland

25

Neutrino cross sections at low energy(Bodek)

% Quasi-Elastic / Elastic (W=Mn)– νµ + n µ- + p & Input from both Electron and

Neutrino Experiments and and described by form factors

% Resonance (low Q2, W< 2)νµ + p µ- + p + π

& Can be well measured in electonscattering but poorly measured in neutrino scattering (fits by Rein

and Seghal

% Deep Inelastic– νµ + p µ- + X& well measured in high energy

experiments and well described by quark-parton model (pQCD with NLO PDFs, but doesn’t work well at low Q2).

' Resonance scattering and low Q2 DIS contribution meet, (difficult to avoid double counting problem ).

& Challenge: to describe all these three processes at all neutrino (or electron) energies.

Issues at few GeV

Generator Physics Overview(Gallagher)

NuTeVMINOS Contained Atmos ν

Eν(GeV)101 102100

PhysicsProcess:

Primarily Quasi-Elastic

QEL, RES,DIS

Predominantly deepinelastic scattering (DIS)

Target: Single Nucleon ? ‘free’ quarks

Good: quark parton modelperturbative QCD

Good: free nucleon ?Theory:Nuclear Physics..

Data: Low Eν bubblechamber data: ANL,

BNL, Gargamelle

Bubble Chamber:BNL, ITEP, BEBC

Good: High StatisticsCCFR,NuTeV, CHARM...

CIPANP WG1 Summary: Burkert, Deshpande, McFarland

27

Fit with ξwPredictions modified GRV98 PDFs

(Bodek)

from Bodekand Yang, a

unified description of all this data!

Photo-production (P)F2(P) resonance

Neutrino Xsection on iron at 55GeV (CCFR)

PWIA and Quasi-Free Kinematics

Nuance

Yie

ld

0.6 GeV^2

1.3 GeV^2

Data on A(e,e’p) also gives information about the modeling of final state interactions.

Proton yield relative to q.

(Gallagher)

Steve Wood: compare ν MC to electron data


29

A Fruitful Collaboration…

!NuInt workshop series"driven by need to understand GeV cross-

sections at K2K, Mini-BooNE!JLab E03-110 (Bodek, Keppel) proposed to

study resonances in nuclei (ν detectors)!High rate ν experiments at FNAL?

"FINESSE (Booster, ~1 GeV): ∆s, exclusive σ"MINERνA (MINOS beam, few GeV): exclusive σ,

DIS regime, nuclear targets…

HEP/NP

collaborations!


30






NUMI, J-PARC


Future e-A collidersWG1/WG10 - Physics at eRHIC, ELIC, HERAIII

R. Ent Physics with ELIC at JLabR. Milner Physics with eRHIC at BNLD. Pitzl HERA III PhysicsS. Chattopadhyay JLab Overview


31

Scientific Highlights for Electron-Ion Colliders

! nucleon structuresea quarks and gluespin and flavor structurenew parton distributions

! Meson structureπ, K are Goldstone Bosons of QCDessential to nuclear binding

! hadronizationevolution of parton into hadronprocess in nuclei of fundamental interest

! nucleirole of partonsinitial conditions for relativistic heavy ion collisions

! matter under extreme conditionssaturation of parton distributionsnew phenomena, e.g. colored glass condensate

(Milner)


32

ELIC Layout One accelerating & one decelerating pass through CEBAFIon Source

IR

IR

Beam Dump

Snake

Snake

CEBAF with Energy Recovery

5 GeV electrons 50-100 GeV light ions

Solenoid

Injector

ECM up to 45 GeV

(Ent, Chattopadhyay)

25 GeV Fixed Targetis an option

Complementarity of 25-GeVfixed-target and ELIC for this

example! # Glue at low Q2

1

10

10 2

10-3

10-2

10-1

1xBj

Q2

(GeV

2 )

ELIC

W2 > 4 GeV2

W2 > 1.2 GeV2>>

Luminosity of up to 1035 cm-2 sec-1


33

eRHIC collider layout ! e-ring is 5/16 of RHIC ring ! Collisions at one IP! 28 MHz collision rate! Unpolarized electron source! Electron beam polarization by

the synchrotron radiation! e-ring lattice based on

”superbend” magnets

p

e 2GeV (5GeV)

2-10 GeVIP12

RHICp 50-250 GeVAu 100 Gev/u

ep -> eX

Kinematic Range

10 x

250

GeV

12 G

eV

Fixe

d Ta

rget

0.0001 0.001 0.01 0.1 1.0

x

110

100

1000

10000

Q^2

(Milner)


34


35

Parameters for Electron-Ion Colliders

e- /e+?e+/e-e+/e-Leptons

103510331031L, cm-2/sec-1

P, d, 3He (pol)others need study

P, 3He, (pol.) others up to U

p,d, .. CaHadrons

10-410-510-6Xmin

25 - 6520 - 100~ 320Sqrt(s) , GeV

~104~105~106Q2maxep (GeV2)

3 - 72 - 1027Ee , GeV

30 - 15030 - 250920Ep , GeV

ELICLinac x Ring

eRHICRing x Ring

HERA IIIRing x Ring

Machine #Parameters


36

Other topics covered in WG1

D. Goldin Determination of scattering lengths of the p-p atomsin the DIRAC experiment

E. Kinney Measurement of quark hadronization in the nuclear environment

R. Muto Measurement of invariant mass spectra of vector mesondecay in nuclear matter at KEK-PS

B. Fox Neutral pion production in pp collisions (K. Okada) at sqrt(s) = 200GeV at RHIC

M. Islam pp elastic scattering at LHC and nucleon structure


37

Conclusions

!Lepton-Hadron and Hadron-Hadronexperiments still tell us much about QCD"Active and broad programs at both particle and

nuclear physics facilities!New facilities for the future

"JLab upgrade"FNAL and JPARC neutrino beams"Electron-Ion program

Lepton-Hadron and Hadron-Hadron ScatteringPurposes of & Prospects for LH-HHSPurposes of & Prospects for LH-HHSHadron Structure: Particle MotivationDrell-Yan m+m- Production and PDF’sQCD at TeVatronPurposes of & Prospects for LH-HHSGeneralized Parton DistributionsPurposes of & Prospects for LH-HHSRun II Dijets in Single Diffraction (CDF)Run II: Exclusive DPE Dijets ?Purposes of & Prospects for LH-HHSDuality now observed in all unpolarized structure functionsPurposes of & Prospects for LH-HHSNeutrino cross sections at low energyGenerator Physics OverviewPWIA and Quasi-Free KinematicsA Fruitful Collaboration…Purposes of & Prospects for LH-HHSScientific Highlights for Electron-Ion CollidersConclusions

lepton-hadron and hadron-hadron scatteringksmcf/cipanp/summary.pdfi. gialas diffraction at hera w....

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