Selected Physics Topics at the Selected Physics Topics at the Electron-Ion-ColliderElectron-Ion-Collider

• nuclear effects in deep inelastic scattering from fixed target experiments

• prospects for EIC

• TMDs and GPDs at EIC

• Summary

Antje Bruell, JLabECT workshop, July 2008

x and A dependence of the EMC x and A dependence of the EMC effect effect

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QQ22 dependence of the EMC effect dependence of the EMC effect

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NMC vs E665 nuclear dataNMC vs E665 nuclear data

NMC experimental set-up NMC experimental set-up

cancellation of acceptance and luminosity

Gluon Saturation at EIC ?Gluon Saturation at EIC ?

Gluon distribution G(x,Q2)– What can we measure at EIC ?

• Extract from scaling violation in F2: F2/lnQ2

• FL ~ s G(x,Q2) – Other Methods:

• 2+1 jet rates (needs jet algorithm and modeling of hadronization for inelastic hadron final states)

• inelastic vector meson production (e.g. J/)• diffractive vector meson production - very sensitive to G(x,Q2)

222

0

)],([)( QxGVAã*Adt

dAS

t

σ∝→

=

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Gluon Saturation at EIC ?Gluon Saturation at EIC ?

The Gluon Contribution to the The Gluon Contribution to the Nucleon Spin Nucleon Spin

Antje Bruell, Jlab

EIC meeting, MIT, April 7 2007

• Introduction

• G from scaling violations of g1(x,Q2)

• The Bjorken Sum Rule

• G from charm production

The Gluon Contribution to the The Gluon Contribution to the Nucleon Spin Nucleon Spin

Antje Bruell, Jlab

EIC meeting, MIT, April 7 2007

• Introduction

• G from scaling violations of g1(x,Q2)

• The Bjorken Sum Rule

• G from charm production

The Gluon Contribution to the The Gluon Contribution to the Nucleon Spin Nucleon Spin

Antje Bruell, Jlab

EIC meeting, MIT, April 7 2007

• Introduction

• G from scaling violations of g1(x,Q2)

• The Bjorken Sum Rule

• G from charm production

The Gluon Contribution to the The Gluon Contribution to the Nucleon Spin Nucleon Spin

Antje Bruell, Jlab

EIC meeting, MIT, April 7 2007

• Introduction

• G from scaling violations of g1(x,Q2)

• The Bjorken Sum Rule

• G from charm production

Exclusive Processes: Collider Exclusive Processes: Collider EnergiesEnergies

Exclusive Processes: EIC Potential and Exclusive Processes: EIC Potential and SimulationsSimulations

The Gluon Contribution to the The Gluon Contribution to the Nucleon Spin Nucleon Spin

Antje Bruell, Jlab

EIC meeting, MIT, April 7 2007

• Introduction

• G from scaling violations of g1(x,Q2)

• The Bjorken Sum Rule

• G from charm production

The Gluon Contribution to the The Gluon Contribution to the Nucleon Spin Nucleon Spin

Antje Bruell, Jlab

EIC meeting, MIT, April 7 2007

• Introduction

• G from scaling violations of g1(x,Q2)

• The Bjorken Sum Rule

• G from charm production

5 GeV 5 GeV 50 GeV/c 50 GeV/c

(e(e P) P)

Q2=4 GeV2

2= 0.2

P’ tagging required– Exclusivity Resolution

σ() ≈ 0.3GeV2 without tagging

• Transverse Imaging

Exclusive charged pion production

-t (GeV2)

Γ d

σ/d

t (u

b/G

eV2)

-t (GeV2)

Γ d

σ/d

t (u

b/G

eV2)

Detect the neutron Missing mass reconstruction

• Neutron acceptance limits the t-coverage• The missing mass method gives full t-coverage for x<0.2

Assume dp/p=1% (pπ<5 GeV)

Ee=5 GeVEp=50 GeV

0.01<x<0.02 0.02<x<0.05 0.05<x<0.1

10<Q2<15

15<Q2<2035<Q2<40

10<Q2<1515<Q2<20

35<Q2<40

0.05<x<0.1

Assume: 100 days, Luminosity=10E34

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Unpol. DF

Helicity

Transversity

Transversity and friendsTransversity and friends

Sivers function

Boer-Mulders function

q(x)

q(x)

q(x)

⊥Tf1

⊥1h

⊥Lh1

⊥Th1

Tg1

EIC workshop, May 21th 20R.Seidl: Transversity measurements at EIC

R.Seidl: Transversity measurements at EIC 21

EIC workshop

, May 21th

First successful attempt at a global analysis for the transverse SIDIS and First successful attempt at a global analysis for the transverse SIDIS and the BELLE Collins datathe BELLE Collins data

HERMES AUT p data

COMPASS AUT d data

Belle e+ e- Collins data

Kretzer FF

First extraction of transversity (up to a sign)

Anselmino et al: hep-ex 0701006

What can be expected at EIC?What can be expected at EIC? Larger x range

measured b y existing experimentsCOMPASS ends at ~

0.01, go lower by almost one order of magnitude, but asymmetries become small

Have some overlap at intermediate x to test evolution of Collins function and higher twist but at higher Q2

EIC workshop, May 21th R.Seidl: Transversity measurements at EIC 22

The Gluon Contribution to the The Gluon Contribution to the Nucleon Spin Nucleon Spin

Antje Bruell, Jlab

EIC meeting, MIT, April 7 2007

• Introduction

• G from scaling violations of g1(x,Q2)

• The Bjorken Sum Rule

• G from charm production

Sivers effect: Kaon electroproduction

• The low x of EIC makes it ideal place to study the Sivers asymmetry in Kaon production (in particular K-). • Combination with CLAS12 data will provide almost complete coverage in x

EIC

CLAS12

ELIC

Vanish like 1/pT (Yuan)

Correlation between Transverse Spin and Momentum of Quarks in

Unpolarized TargetAll Projected Data

Perturbatively Calculable at Large pT

Summary

• eA data from fixed target experiments insufficient to constrain nuclear gluon distribution

• large kinematic range of EIC will provide precision data on e.g. Q2 dependence of F2

A/F2D and x dependence of FL

A/FLD and will thus

allow to investigate the low x phyiscs of saturation in the nucleus

• high luminosity and large kinematic coverage will allow to do gluon and quark “tomography” via exclusive processes (measurement of fully differential cross sections for diffractive and non-diffractive channels)

• single spin asymmetries will determine transverse spin effects and get access to orbital momenta