A Novel Spin-Light Polarimeter for the Electron Ion Collider
Selected Physics Topics at the Electron-Ion-Collider
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Transcript of Selected Physics Topics at the Electron-Ion-Collider
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