Future lepton scattering facilities

NuPECC working group

Tullio Bressani, INFN, Torino Univ.Jens Jørgen Gaardhøje, Niels Bohr Inst.Günther Rosner, Glasgow Univ. (chair)

Hans Ströher, FZ Juelich

(No externals yet)

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Laboratories

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EIC?

DESY: HERMES28 GeV e+, e-

L = 1032

H1, ZEUS

FZ Jülich: COSY2.5 GeV p

Cooler Ring

MAMI:1.5 GeV e-, L = 1038

108/s

CERN: COMPASS μ+, μ-, hadrons

200 GeV, L = 1032

ALICE

LHeC?

ESRF: GRAAL106/s 1.5 GeV

LNF: DANEe+e- Collider

16 MeV K, L = 1032

DANE 2?Super B?

FAIR: PANDA15 GeV anti – p

Cooler RingL = 2x1032

PAX?CBM

ELSA:3.5 GeV e, L = 1034

107/s

TSL: Celsius1.3 GeV p

Cooler Ring

MAX-lab:0.25 GeV

RHIC:100+100 GeV

p/A

JLab:6 GeV e- , L = 1038

107/s

12 GeV upgrade

Key questions in hadron physics

Mechanism of quark confinement Generation of hadron masses

Spontaneous chiral symmetry breaking QCD vacuum, quark condensates

Nucleon structure Transverse structure Spin puzzle Parton correlations Gluon density saturation

New forms of hadronic matter Exotic multi-quark states Exotic mesons Glueballs

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Nucleon

Experimental & theoretical challenges

Experimental frontier High precision High luminosity Polarisation

Beam Target Pol. Transfer

Higher c.o.m energies!

Theoretical symbiosis Effective field theories Lattice QCD Perturbative QCD

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Generalised Parton Distributions Measure hard

exclusive reactions

at HERMES, COMPASS PANDA JLab 12GeV EIC

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The nucleon spin puzzle

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HERMESCOMPASSRHIC-Spin

EIC

HERMES, COMPASS PANDA, PAX

HERMESCOMPASS

JLab 12 GeVPANDA EIC

Gluon polarisationpositive (HERMES)negative (SMC)

Gluon orbitalangular momentum(accessible through GPDs, difficult)

Quark orbitalangular momentum(accessible through GPDs)

Transversity

HERMES: 0.3

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Nucleon tomography via GPDs

European issues

Since the 1980’s ELFE @ Saclay (≥2 GeV e- fixed target) ELFE @ DESY (≥10 GeV e- fixed target) ELFE @ CERN (≥20 GeV e- fixed target) EIC @ GSI (ep/eA collider) TESLA N (≥200 GeV fixed target) EVELYN @ DESY (≥50 GeV fixed target)

Problems Difficult international environment No adequate host lab

What do we learn from this history?

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USA: Electron-Ion Collider 20-100 GeVcom

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An Electron-Ion Collider (EIC) with polarized beams has been embraced by the U.S. nuclear science community as embodying the vision for reaching the next QCD frontier. EIC would provide unique capabilities for the study of QCD well beyond those available at existing facilities worldwide and complementary to those planned for the next generation of accelerators in Europe and Asia. In support of this new direction:

We recommend the allocation of resources to develop accelerator and detector technology necessary to lay the foundation for a polarized Electron Ion Collider. The EIC would explore the new QCD frontier of strong color fields in nuclei and precisely image the gluons in the proton.

NSAC 2007

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Develop the Science Case Choose Site? Develop Sound Cost Basis What is cost versus science tradeoff Secure the NP doubling budget LRP 2012 very important (i.e. critical?) for EIC

Robert Tribble, 7 Dec 2007

NSAC

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CERN: Large Hadron electron Collider

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Parton distribution functions

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LHeC double rings

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LHeC roadmap

Feasibility study endorsed by CERN and ECFA First ECFA-CERN Workshop on the LHeC in Divonne,

1-3/9/08 Goal: Conceptual Design Report by end of 2009,

early 2010, on: Accelerator Interaction regions Detector Infrastructure Physics

New Physics High Precision QCD + electroweak High parton densities (low x + eA)

http://www.lhec.org.uk

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Kinematic coverage

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(Optimistic) Timelines 2007:

Accelerators MAX-lab, MAMI C,

BEPCII, LHC, JPARC Experiments

HERMES, COMPASS, BESIII, WASA, ALICE

> 2012: Accelerators

JLab 12 GeV, FAIR, DAFNE 2?, Super-B factory?, RHIC 2?

Experiments CLAS 12, GlueX,

PANDA, CBM, COMPASS?, KLOE 2?, Super-BELLE?

> 2017: Accelerators

Proton-antiproton collider at FAIR?

EIC? Experiments

PAX? Electron-ion exp.?

> 2022: Accelerator

LHeC?

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