BNL-96357-2011-CP Summary of “Future of DIS” Working Group Session

Vadim Guzey1, Matthew A. C. Lamont2 and Alessandro Polini3

1 Jefferson Lab, Newport News, VA 23606, USA

2 Brookhaven National Lab, Upton, NY 11973, USA 3 INFN Bologna, via Irnerio 46, 40126 Bologna, Italy

September 2011

Physics Department

Brookhaven National Laboratory

U.S. Department of Energy DOE Office of Science

Notice: This manuscript has been co-authored by employees of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The publisher by accepting the manuscript for publication acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. This preprint is intended for publication in a journal or proceedings. Since changes may be made before publication, it may not be cited or reproduced without the author’s permission.

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Summary of “Future of DIS” Working GroupSession

Vadim Guzey∗, Matthew A. C. Lamont† and Alessandro Polini∗∗

∗Jefferson Lab, Newport News, VA 23606, USA†Brookhaven National Lab, Upton, NY 11973, USA∗∗INFN Bologna, via Irnerio 46, 40126 Bologna, Italy

Abstract. Despite the closure of the HERA accelerator in the past few years, much physics stillremains to be understood, from the quark and gluon content of the nucleon/nucleus across all x tothe still unknown spin structure of the proton. The “Future of DIS” working group was dedicatedto discussions on these and many other subjects. This paper represents a brief overview of thediscussions. For further details, please refer to individual contributions.

Keywords: Deep Inelastic Scattering, Future HEP FacilitiesPACS: 01.52.+r, 12.38.Qk, 25.30.-c, 29.20.db, 29.20.Ej, 29.27.Hj, 29.40.-n, 29.90.+r.

INTRODUCTION

We present an overview of the contributions and discussions at the Working Group 7on the “Future of Deep Inelastic Scattering” at the DIS 2011 workshop in this paper.Due to space limitations, not all presentations can be summarized here. During the 10parallel sessions, 46 contributions were presented (8 of them in combined sessions),always followed by lively discussions which are the best indicator of the strong interestand the large involvement of the community towards future projects.

In the following sections we will focus on the physics potential at the three main newinitiatives in the field: i) the 12 GeV upgrade at Jefferson Lab, ii) an electron-ion colliderin the US and iii) an electron-proton and electron-ion collider at CERN’s LHC. Beforethe concluding remarks, a concise overview of other DIS experiments and upgrades atCERN, DESY, FermiLab and RHIC are presented.

JLAB AT 12 GEV

Jefferson Laboratory (JLab) has been providing high-precision data on electron-nucleon/nucleus scattering using 4 to 6 GeV/c electron beams since 1995. The labo-ratory is now in the process of the energy upgrade to 12 GeV which started in May2011 and is expected to be completed by June 2015. The upgrade consists of installingnew equipment (10 additional cryomodules with accelerator cavities and one beam-linearc) and a new experimental hall (Hall D) as well as enhancing the capabilities of theexisting experimental halls and detectors in Halls A, B, and C [1].

The highlights of scientific capabilities of different JLab halls after the 12 GeVupgrade are summarized in Table 1. As DIS at JLab at 12 GeV accesses the region of

xBQ

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qaa�

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0.2 0.3 0.45 0.6

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FIGURE 1. Left: Projections for the kinematic reach and errors on the d/u ratio that will be measured atJLab at 12 GeV [2]. The shaded band represents the present uncertainty in this quantity. Right: Kinematiccoverage in Q2, x and t of the projected beam-spin DVCS asymmetry ALU with the proton target at JLabat 12 GeV [5].

large Bjorken x≥ 0.1, it will provide unprecedentedly high precision studies of valencequarks in the nucleon/nuclei.

TABLE 1. Highlights of scientific capabilities of different JLab halls after the 12GeV upgrade.

Hall A Structure functions at large x, nucleon elastic form factors, GPDs,short-range NN correlations, hyper-nuclear physics, electroweak physics

Hall B Structure functions, GPDs, TMDs,baryon and meson spectroscopy, hadronization

Hall C Structure functions at large x, nucleon elastic form factors,nuclear structure functions, colour transparency, hadronization

Hall D Search for exotic mesons and meson spectroscopy

Different approaches to the nucleon wave function make distinct predictions for theratio of the d/u quark distributions (directly related to the ratio of the neutron andproton structure functions, F2n/F2p) in the xB→ 1 limit. Presently this ratio has a largeuncertainty for xB > 0.6 due to the ambiguity associated with nuclear corrections sinceF2n is extracted from nuclear data (the uncertainty is presented by the shaded yellowband in the left panel of Fig. 1). A new experiment at JLab Hall A (MARATHONCollaboration) will circumvent this problem by measuring DIS off the mirror nucleiof 3He and 3H [2]. The projected improvement and kinematic reach for the d/u ratio ispresented by the points with error bars in the left panel of Fig. 1.

The neutron spin asymmetry An1 at large x measured in polarized DIS tests the hypoth-

esis of hadron helicity conservation, pointing to the presence of non-zero quark orbital

angular momentum and affects the flavour decomposition of the ratio of the polarizedto unpolarized quark distributions ∆q/q. The measurements are challenging since theyrequire high luminosity (3−10×1036 cm−2s−1) and high beam and target polarizations.These requirements are met at JLab where new measurements at Hall A (using the Big-Bite spectrometer) and Hall C (using the SHMS and HMS spectrometers), with a newgeneration polarized 3He target, will determine An

1 with unprecedented precision up tox = 0.75 [3]. Also, the measurements of the proton and deuteron spin asymmetries Ap

1and Ad

1 , respectively, will be carried out at Hall B using the CLAS detector [4].One of the flagship experiments at JLab at 12 GeV will be a dedicated program

of measurements of exclusive reactions (deeply virtual Compton scattering – DVCSand the production of vector and pseudo-scalar mesons) that access mainly valencequark generalized parton distributions (GPDs). GPDs encode information on three-dimensional distributions and correlations of partons in hadrons; GPDs give access tothe total angular momentum of partons and, thus, provide an insight into the spin andflavour structure of the nucleon. Taking advantage of the beam and target polarizations(longitudinal and transverse polarizations for the latter) and wide acceptance of theupgraded CLAS detector, DVCS and the production of ρ and π mesons with protonand neutron (deuteron) targets will be measured at Hall B with CLAS [5]. An exampleof the kinematic coverage in Q2, x and t and the projected beam-spin DVCS asymmetryALU with the proton target is presented in the right panel of Fig. 1. It is expected thatthe resulting data will not only constrain various Compton form factors in the valenceregion, but will also enable one to perform the global analysis and extraction of thevalence quark GPDs.

Semi-inclusive DIS (SIDIS) provides the information on the structure of the nucleonwhich is complementary to that obtained in inclusive DIS and hard exclusive scattering.JLab at 12 GeV (Halls A, B, and C) has an extensive program of SIDIS measurementswhich access transverse momentum dependent parton distributions (TMDs). (SIDISis also traditionally used for flavour separation of the usual collinear parton distribu-tions [6].) TMDs encode detailed information on the nucleon wave function (the distri-bution of partons in the longitudinal light-cone fraction and transverse momentum, theparton spin-orbit correlations, etc.) and on QCD dynamics (Wilson links, factorizationand universality). Using the transversely polarized 3He target and the solenoidal detectorfor DIS (SoLID), Hall A will measure TMDs characterizing the transversely polarizedtarget (Sivers function, transversity, pretzelosity, worm-gear functions) and will be ableto perform their flavour separation [7]. In Hall C, one will measure the transverse mo-mentum dependence of pion production in SIDIS and will perform its flavour separationby detecting π+ and π− and using the proton and deuteron targets [6].

THE ELECTRON ION COLLIDER

As described above, the JLab 12 GeV project will increase our knowledge of the struc-ture of the nucleon in the valence quark region. In order to increase our understandingat smaller x of both the nucleon and nuclei, higher energies are required. To this end, aproposal exists which would see the building of an electron-ion collider (EIC) in the USon the timescale of the next decade [8]. Two proposals currently exist for bringing such

a machine to fruition, one requires adding a hadron accelerator to the 12 GeV e− accel-erator at JLab, the other requiring the addition of an electron accelerator to the existingpolarised hadron machine at Brookhaven National Lab (BNL). While the BNL designshould be significantly cheaper, the JLab design will be the first hadron machine built ina number of years that may be able to take advantage of newer technologies. We will notgo into the machine designs themselves here, nor the different staging options, rather,details are given elsewhere [9, 10, 11].

Although there are competing designs for the machine, the physics goals that each candeliver are broadly the same. Low-energy designs can deliver centre-of-mass energiesup to

√sNN ∼ 50 GeV whilst full energy options can go up to

√sNN ∼ 150 GeV. This

extends the x,Q2 reach of an EIC well into the range where sea-quarks and, in particular,gluons, are dominant. In the autumn of 2010, there was a 10-week programme at theInstitute for Nuclear Theory (INT, Seattle) where the physics capabilities of an EICwere discussed extensively. A report from this meeting is currently being published andcan be found on the arXiv [12]. They fall into the following 4 broad areas:

1. The spin and flavour structure of the proton2. The three-dimensional structure of both nucleons and nuclei in momentum and

configuration space3. QCD matter in nuclei4. Electroweak physics and the search for physics beyond the standard model

Whilst HERA was able to collide leptons and hadrons at higher energies than a pro-posed EIC, an EIC, with much higher luminosity, can still make important contributionsto our understanding of the flavour composition of the nucleon through measurementsof the longitudinal structure function, FL, the strangeness and anti-strangeness densitiesand the heavy flavour contributions to DIS. However, what will make the EIC uniquewill be the ability to collide polarised electrons and polarised protons at high energiesand hence its contribution to the measurement of ∆g(x) [8, 13, 14, 15, 16, 17].

Current constraints on ∆g(x) come from DIS and SIDIS data from HERMES andCOMPASS, together with the RHIC p+p dataset which pin the ∆g(x) distribution downto x values of a few times 10−2. However, even with these constraints, extrapolationsdown to small-x can still hide up to one unit of h̄, i.e., twice the nucleon spin! Therefore,measurements need to be made to lower x in order to constrain the gluon contribution tothe nucleon spin. Fig. 2 shows how this can be accomplished at an EIC through a globalQCD fit of helicity-dependent PDFs based upon the DSSV framework. Pseudo-datawere generated with the PEPSI Monte-Carlo code for different e+p energies, rangingfrom 5x50 GeV to 5x325 GeV (i.e. this measurement could be performed at a stage-1eRHIC). The left side of Fig. 2 shows how the width of the χ2 profile for ∆g(x) changesas we go from the current data (labelled DSSV+) through the various EIC datasets,where the width constrains the uncertainties in ∆g(x). The right side of Fig. 2 showshow both the shape and the uncertainties in ∆g(x) are constrained when the EIC pseudo-data for the spin asymmetry (A1) is included, down to 10−4 in x.

As well as measuring the flavour- and spin-structure of the nucleon, an EIC will havea large input on the gluon distribution in nuclei in both momentum and configurationspace [18, 19, 20, 21, 22]. In contrast to the nucleon, almost no information is currently

∆χ2∆χi

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x

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0

0.1

0.2

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10-5

10-4

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10-2

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1

FIGURE 2. χ2 profiles for the truncated x integral of ∆g (l.h.s.) and uncertainty bands for x∆g referringto ∆χ2/χ2 = 2% (r.h.s.) with and without including the generated EIC pseudo-data in the fit.

known about gluons in nuclei, with existing experiments only measuring at high-x.One of the highlights of the e+A programme at an EIC is the ability to search for

gluon saturation at small-x. Data from HERA on the scaling violation of F2 in thenucleon have shown that the gluon distribution rises sharply as x decreases and indeedsignificantly dominates the structure for x < 10−2. It is believed that higher x gluonsradiate smaller x gluons via the process of Bremsstrahlung, causing an avalanche ofgluons at small x, leading to a regime where the gluons are so closely packed that non-linear QCD is required to describe the strong colour fields. A description of the datain linear QCD (DGLAP) breaks down at small-x as it predicts an ever-increasing rise ofthe gluon distribution. However, the Froissart Unitarity Bound, which states that the totalcross-section cannot grow faster than the square of the logarithm of the energy, placesa limit on the gluon distribution [23]. This means that at smaller values of x, the gluondistribution must saturate. This can be visualised as low-x gluons recombining at highdensities to counteract the Bremsstrahlung process described above and is described by asaturation scale, QS. The values of x at which saturation occurs in a nucleon is predictedto be well below what can be achieved at an EIC, however, this may be possible at anLHeC which will be described in the next section.

Although saturation cannot be probed in e+p collisions at an EIC, it will be possible tomeasure in e+A collisions. It has been shown that, from simple geometrical considera-tions, the saturation scale has a dependence on A1/3. In turn, this means that the effectivex probed in e+A collisions is smaller by at least 2 orders of magnitude. This is repre-sented in Fig. 3-left which shows the saturation scale as a function of x for protons, Caand Au.

In order to measure saturation phenomena, one must have good experimental observ-ables. By measuring the inclusive structure functions, it is possible to make a measure-ment of the gluon distribution either indirectly through F2 (a la HERA) or indirectlythrough FL. FL is the more desirable measurement but is experimentally more challeng-

1/x

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x

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0 0.1 0.2 0.3 0.4 0.5 0.6

proton, <N>L, bCGC

HERA

1e-05 0.0001 0.001

x

1

10

100

Q2 [G

eV2 ]

proton, <N>L, bCGC

EIC

1e-05 0.0001 0.001

x

1

10

100

Q2 [G

eV2 ]

Au nucleus, <N>L, bCGC

0.2 0.3 0.4 0.5 0.6

1e-05 0.0001 0.001

x

1

10

100

Q2 [G

eV2 ]

0 0.1 0.2 0.3 0.4 0.5 0.6

Au nucleus, <N>L, bCGC

EIC

1e-05 0.0001 0.001

x

1

10

100

Q2 [G

eV2 ]

Au nucleus, <N>L, bCGC

mEIC

1e-05 0.0001 0.001

x

1

10

100

Q2 [G

eV2 ]

FIGURE 3. Left: The dependence of QS on x for different nuclei. Right: The longitudinal mean scatter-ing amplitude, 〈N 〉L, for protons and Au nuclei.

ing and it requires running at a number of different energies, something which an EICwill be designed to do. For example, RHIC (a key component of the eRHIC design) hasalready exhibited the ability to collide heavy-ions at beam energies from 3.5 GeV/A upto 100 GeV/A and it is expected that in the EIC era, this can be increased up to 130GeV/A. The contrast in the saturation reach in e+p and e+A collisions at an EIC can bevisualised through determining the mean scattering amplitude, given in equation 1:

〈N 〉T,L =

∫d2rT

∫ 10 dz

∣∣∣Ψγ∗

L,T

∣∣∣2 ∫ d2bT N 2(x,bT ,rT )∫d2rT

∫ 10 dz

∣∣∣Ψγ∗

L,T

∣∣∣2 ∫ d2bT N (x,bT ,rT )(1)

That is, the expectation value of the scattering amplitude weighted by the cross-section of a particular process which gives a value between 0 and 1, where 0 wouldrepresent a dilute system and 1 a saturated system. Fig. 3-right shows the mean scatter-ing amplitude probed in the longitudinal total cross section in a proton and Au nucleusrespectively within the IPSat saturation model. One can see that for protons, the sat-uration region is not penetrated at an EIC whilst for Au nuclei, even in a low-energy(staged) EIC, it is possible that saturation could be probed.

Although of high interest, saturation phenomena do not represent the full e+A pro-gramme at an EIC. Also of particular interest are measurements at higher x of partonpropagation and hadronization in a nuclear medium. Currently, experiments at RHICand the LHC on relativistic heavy-ion collisions are providing a wealth of data pointingtowards the creation of a new state of matter where quarks and gluons are not boundinto hadrons - a Quark Gluon Plasma (QGP). However, in order to make quantitative

measurements of partons passing though hot nuclear matter, one must first make mea-surements of how they behave as they pass through cold nuclear matter. Important firststeps in the study have been performed by the HERMES experiment at HERA, wheremultiplicity ratios of identified hadrons were made as a function of ν , z and Q2. Theseshowed an attenuation at small ν and large z akin to what is observed in RAA mea-surements at RHIC and the LHC in heavy-ion collisions [24, 25]. However, the smallkinematic range, due to it being a “fixed-target” experiment means that experiments atan EIC will have a crucial role in underpinning this physics due to the much larger kine-matic range available at an EIC. By being able to study interactions as a function of ν , itwill be possible to study hadrons that are formed both inside and outside of the nucleus.In fact, the ν range at an EIC will be 50 times that of HERMES.

Although just briefly mentioned in the DIS conference, it is important to note thatwhilst an EIC would be used for investigations of the strong interaction, it can alsoprovide important information on electroweak physics. For instance, constraints on theweak mixing angle can be achieved by looking for parity violating asymmetries in e+pand e+d DIS [8].

DEEP INELASTIC SCATTERING AT THE LHEC

The Large Hadron Electron Collider (LHeC) [26, 27] is a proposed colliding beam fa-cility at CERN which will exploit the LHC for lepton-nucleon scattering at an unprece-dented centre of mass energy. With a design luminosity of about 1033cm2s−1, the LHeCexceeds the integrated luminosity collected at HERA by two orders of magnitude andextends the kinematic range by a factor of twenty in the four-momentum squared, Q2,and in the inverse x. This would extend the physics of deep inelastic scattering to theterascale with significant improvements in the following areas:

• The unfolding of the partonic structure of the proton• The exploration of higher energy scales, complementing the LHC measurements• The search of new physics in the e−q sector• The study of parton saturation at low x and the parton structure of nuclei

Fig. 4-left displays past, present and future DIS facilities, in the centre of massenergy and the instantaneous luminosity plane. Fig. 4-right shows the LHeC x andthe momentum transfer squared Q2 phase space, compared to HERA and fixed targetexperiments with some of the physics topics underlined.

To evaluate the feasibility of the project and propose a design, an LHeC study grouphas been set with the focus on the physics program and the machine and detector design.Several workshops and activities in collaboration and support from ECFA, CERN andNUPECC, have been organized aiming at the preparation of a Conceptual Design Report(CDR), to be released in 2011.

The LHeC is planned for the LHC phase II upgrade, i.e. for the LHC running in the2020s when luminosities of 1035cm−2s−1 for 7+7 TeV proton-proton collisions will bereached. For the electron beam, two configurations are presently being pursued. In thefirst, the electron beam circulates in the existing LHC tunnel with a nominal energy of

29  

Deep Inelastic e/μ p Scattering  

FIGURE 4. Left: Past, present and future Deep Inelastic Scattering experiments. Right: Kinematic planein x and resolving power, Q2, showing the coverage of fixed-target experiments, HERA and the LHeC.The mapping of the planned physics programme onto this plane is also indicated.

60 GeV, the energy and the luminosity being limited by the requirement of a maximumpower consumption of 100 MWatts. A complete design of the arc dipole magnets, theinjection scheme, the interaction region and the bypass tunnels for the electron beampassing the existing LHC experiments have been established [28]. As for HERA, thereach of the highest luminosity has the drawback of requiring additional strong focusingmagnets close to the interaction region, possibly compromising the detector acceptance.Two options have been considered: the first with a detector coverage limited at 10◦, thesecond leaving the detector area free from additional magnets allowing an acceptancedown to ≈ 1◦. An alternative solution to the Ring-Ring approach for the electron beam,less invasive with respect to the existing LHC tunnel, is the construction of a linearaccelerator complex, with options for energy recovery which would also allow runningwith a polarized electron beam [29]. Some of the main machine and beam parametersfor these options are summarized in Table 2. A choice between the two configurations isenvisaged soon after the appearance of the CDR. It is important to consider that the Ring-Ring configuration delivers high electron and positron luminosity, with difficulties forhigh polarisation, while the Linac-Ring configuration has a high potential for polarisedelectrons but difficulties to deliver an intense positron beam, yet offering also a photonbeam option.

The fact that the LHeC has to run concurrently with the other LHC experiments putsnot only an additional challenge for the complex interaction region where 3 beams (theinteracting proton and electron beam and the second spectator proton beam) will besteered and focused, but also the construction of the experiment and the acceleratinginfrastructure has to follow the LHC schedule.

The detector structure will have to be modular, partially built at surface level andadequate to fit in the complex interaction region. Moreover, the physics to be studied

TABLE 2. LHeC Parameters for the different electron accelerator options

Ring-Ring 10◦ Ring-Ring 1◦ ER Linac-Ring Linac-Ring

Average current [mA] 100 100 6.6 5.4

e energy [GeV] 60 60 60 140

Luminosity [1032cm−2s−1] 13.4 7.33 10 0.44

polarization [%] < 40 < 40 90 90

Crossing angle [mrad] 1 1 0 0

Total wall plug power [MW] 100 100 100 100

requires a detector with the highest acceptance in the forward and backward direction,along with precise vertexing and excellent energy resolution. A detector design satisfy-ing these requirements has been presented in detail [30]. The LHeC detector is modularand asymmetric in the design as required by the large imbalance of the beam energiesand provides excellent tracking resolution by means of multiple layers of silicon trackingdown to ≈ 1◦ forward and backward and an electromagnetic calorimetry all containedin a 3.5 T superconducting solenoid.

The very diversified LHeC physics program is devoted to an exploration of the en-ergy frontier, complementing the LHC measurements [31, 32, 33, 34] and its discoverypotential for physics beyond the Standard Model [35] with high precision DIS mea-surements. These are projected to solve a variety of fundamental questions in strongand electroweak interactions. With an e±p centre of mass energy of 1.5 TeV the LHeCwould be the world’s cleanest high resolution microscope, designed to continue the pathof deep inelastic lepton-hadron scattering into unknown areas of physics and kinematics.

The determination of the parton distribution, one of the main legacies of HERA, canbe further enhanced. Fig.5 shows an example of the present uncertainty in the gluon andquark densities as a function of logx superimposed with those extrapolated assuming theLHeC [36].

Running the LHeC with heavy ions would further extend the (Q2, 1/x) range allowingfor the study of parton densities in nuclei which are very little known at the present andwould shed light on saturation and non-linear effects in the parton evolution which,for heavy nuclei, are enhanced by about two orders of magnitude in x (Q2

S ∝ x−λ A1/3;λ ' 0.3). Finally the LHeC would be a major opportunity for progress in particle physicsand further exploits the investment made in the LHC.

OTHER EXPERIMENTS

As well as many talks on future experiments at the upcoming facilities mentionedin the previous sections, there were also a number of talks on upgrades to currentexperiments. The PHENIX [37] and STAR [38] experiments at RHIC presented theoutcomes of recently produced decadel plans by each experiment, where the future p+pand A+A running were envisaged along with a transition to being part of a future eRHIC.Interestingly, two different approaches were presented. STAR’s approach is to add minor

FIGURE 5. Relative uncertainty of the gluon and valence u quark distributions at Q2 = 1.9 GeV2, asresulting from an NLO QCD fit to HERA I data, and to HERA I and simulated data from the LHeC. Twoscenarios are considered. B: L = 50 fb−1, Ep = 7 TeV, Polarization 0.4; H: L = 1 fb−1, Ep = 1 TeV, nopolarization.

upgrades to the current configuration, particularly in the vertex region and PHENIXare planning a large overhaul and replacing most of what currently exists. As wellas these two well-known experiments, plans for the AnDY experiment at RHIC werealso presented [39]. As the name suggests, this experiment is focused on measuring thesingle-spin left-right asymmetry (called AN) in the Drell-Yan process in p+p collisions,which is believed to be opposite in sign to the same asymmetry in DIS. This is a smallexperiment, utilising hadronic calorimetry left over from previous BNL experimentscombined with electromagnetic calorimetry borrowed from JLab. We look forward toseeing the results in the near future.

Although LHC operations and upgrades are the main focus at CERN right now (see,for instance, the talk on ATLAS upgrades [40]), we also had two talks on upgrades tothe COMPASS experiment where again, one of the prime measurements will be that ofDrell-Yan [41, 42].

Finally, there were presentantions of neutrino DIS in the MINERνA experiment [43]as well as an update on the OLYMPUS experiment at DESY which utilizes the DORISstorage ring, [44]. The aim of the project is the measurent of the two photon contributionto elastic e±p scattering which would explain the discrepancy observed at JLab inthe ratio of the electric to magnetic elastic form factors at high momentum transfer(Q >> 1GeV/c2).

CONCLUSIONS

As can be taken from the attendance and discussion in the “Future initiatives in QCD”working group, the future of DIS and related subjects is indeed lively. It has been apleasure to assist in first person the discussion within the working group and we wouldlike to thank all participants for their contributions. Please see the list of references atthe end of this paper. We would especially like to mention the plenary contribution on“Future Initiatives in QCD” by Robert Klanner [11].

ACKNOWLEDGMENTS

Thanks to the organizers of the workshop, in particular Rolf Ent. Our thanks andappreciation goes also to all the speakers for their valuable contributions.

REFERENCES

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2. J. Gomez, “Measurement of Fn2 /F p

2 , d/u RAtios and A = 3 EMC Effect in Deep Inelastic ElectronScattering Off the Tritium and Helium MirrOr Nuclei”, Proc. of XIX Int. Workshop on Deep-InelasticScattering and Related Topics, Newport News, VA, USA, April 2011

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6. D. Gaskell. “Semi-Inclusive DIS in Hall C after the 12 GeV upgrade”, Proc. of XIX Int. Workshopon Deep-Inelastic Scattering and Related Topics, Newport News, VA, USA, April 2011

7. X. Qian,“SIDIs with Polarized 3He and SoLID at 11 GeV JLab”, Proc. of XIX Int. Workshop onDeep-Inelastic Scattering and Related Topics, Newport News, VA, USA, April 2011

8. A. Deshpande, “The Electron Ion Collider Project”, Proc. of XIX Int. Workshop on Deep-InelasticScattering and Related Topics, Newport News, VA, USA, April 2011

9. V. N. Litvinenko, “High-energy high-luminosity electron-hadron collider eRHIC”, Proc. of XIXInt. Workshop on Deep-Inelastic Scattering and Related Topics, Newport News, VA, USA, April2011

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