The Electron Ion Collider User Group Meeting

7 Jul 2016, 01:30 → 9 Jul 2016, 15:30 US/Central

Physics Division Auditorium (Argonne National Laboratory)

Alberto Accardi, Ian Cloet, Kawtar Hafidi (Argonne National Laboratory), Matt Sievert (BNL), Salvatore Fazio, Whitney Armstrong (Argonne)

Please visit the official 2016 Electron Ion Collider User Group Meeting website.
(http://eic2016.phy.anl.gov)


Connect via bluejeans to:

• Physics Division Auditorium
• Room R-150 (parallel sessions only)
• Room E-142 (parallel sessions only)

Thursday, 7 July

13:30 → 15:15 First Day: Opening Session

Session chair: Don Geesaman

13:30 Opening Remarks

Speaker: Harry Weerts

13:45 JLEIC design

Speakers: Fulvia Pilat, Rik Yoshida

Slides JLEIC_status-combined.pptx

14:30 eRHIC design

Speaker: Vadim Ptitsyn

Slides VP_eRHIC_AccDesign.pdf

15:15 → 15:45 Coffee

15:45 → 17:30 First Day: Afternoon

Session chair: Zein-Eddine Meziani

15:45 Updates on the EIC

Speaker: Prof. Abhay Deshpande (Stony Brook University)

Slides EICStatus-07072016.pdf

16:15 Summary of the proton mass workshop

Speaker: Jianwei Qiu

Slides Qiu_EICUG_ANL.pdf

16:45 ANL-EIC group activities

Speaker: Dr Jose Repond (Argonne National Laboratory)

Slides EIC_ANL_Jul_2016.pdf

17:30 → 19:30 Welcome reception

Friday, 8 July

09:00 → 10:20 National Academy’s Review

Session chair: Rolf Ent

09:00 Introduction/overview

Speaker: Barbara Jacak

09:10 NAS experience from FRIB

Speaker: David Dean

Slides 20160708_EIC_Chicago.pptx

09:30 Panel discussion

Moderator: Barbara Jacak Panelists: David Dean Don Geesaman Roy Holt Robert Janssens

10:20 → 10:40 Coffee

10:40 → 12:20 EICUG

Session chair: Charles Hyde

10:40 International Panel

Zein-Eddine Meziani, moderator Silvia Dalla Torre (INFN Trieste) Marco Contalbrigo (INFN Ferrara) Yuji Goto (RIKEN) Bjoern Seitz (University of Glasgow)

11:20 EICUG Status, Plans : A Discussion

Moderators: Richard Milner Rik Yoshida

12:20 → 13:30 Lunch

On your own

13:30 → 15:10 Novel Observables

13:30 Exotic Glue: The Gluonic Transversity Structure Function

In 1989 Jaffe and Manohar described a leading-twist, double-helicity-flipping structure function ∆(x, Q2) which is sensitive to gluonic states in any hadron of spin J ≥ 1, notably in nuclei. For nuclei, this quantity gives a measure of exotic glue—the contributions from gluons not associated with individual nucleons in a nucleus—as neither nucleons nor pions (nor any state with spin less than one) can transfer two units of helicity to the nuclear target. In hadrons this quantity is also of particular interest since, unlike the unpolarised and helicity gluon distributions, the transversity density is a clean measure of gluonic degrees of freedom as it only mixes with quark distributions at higher twist. I will summarize the results of the first lattice QCD study of ∆(x, Q2), namely a calculation of its low moments in hadronic targets. The robust result allows an investigation of the gluonic structure of hadrons more generally, including consideration of the direct gluonic analogue of the Soffer bound for transversity. The work can be extended to light nuclei as well as to off-forward gluon transversity matrix elements in the nucleon. An experimental measurement of ∆(x, Q2) has been proposed in a recent letter of intent to Jefferson Lab, with the goal of measurements at low Bjorken-x on nitrogen targets. Measurements on a variety of light nuclear targets at the Electron-Ion Collider would be of great interest.

Speaker: Phiala Shanahan

Slides ShanahanEICUG2016.pdf

13:55 Search for Exotic Gluonic States in the Nucleus

Although crucial to our understanding of nuclear structure, probes of gluonic components of the nucleus can be elusive, as gluons are accessed only indirectly in deep inelastic scattering. In 1989, Jaffe and Manohar identified a leading-twist double-helicity-flip structure function $\Delta(x,Q^2)$ which is sensitive to exotic gluonic states in the nucleus, and is accessible via an inclusive measurement on a transversely polarized nucleus of spin greater than or equal to 1. We are developing an experiment at Jefferson Lab using a transversely polarized $^{14}$N target and the CEBAF 12 GeV electron beam, which would represent the first exploration of the $\Delta$ structure function. While the Jefferson Lab experiment will probe $\Delta$ from from $x$ of 0.3 to 0.05, the vast kinematic reach of an EIC would allow a thorough probe of this quantity. Such an investigation would directly address the facility’s mission to better understand the glue. We will discuss the impact of exciting new lattice QCD results on this quantity from our collaborators, our proposal to measure $\Delta(x,Q^2)$ at JLab, and what a future measurement might look like at the EIC.

Speaker: James Maxwell

Slides eic_ug_7_8_16.pdf

14:20 Pion and kaon structure functions

Speaker: Tanja Horn

Slides Pi_K_SF_Horn_v3_short.pdf

14:45 Nucleon Distribution Amplitudes

In the past few years, our understanding of the meson internal structure in terms of the 1D distribution amplitudes have scored many progresses. For instance, in the case of the pion, the Dyson-Schwinger equations have allowed to compute within a non-perturbative framework, the pion distribution amplitudes which are significantly different from the asymptotic one. This allows to bring back together the measurements of the pion form factors and our perturbative understanding of the latter in terms of distribution amplitudes. Even if they may be less known, the nucleon distributions amplitudes can also be related the nucleon form factors in the perturbative regime. Therefore, based on what happened for the pion, reliable description of the nucleon form factor cannot be done in this framework with the asymptotic distribution amplitude. I will here describe how one can compute these distribution amplitudes non-perturbatively in the continuum, what they tell us about the nucleon content, and which effects they can have on the form factor at high Q^2.

Speaker: Cédric Mezrag

Slides mezrag_EIC_DA.pdf

13:30 → 15:10 Novel Technical Advancements (Detector / Experiment)

13:30 Spectator Tagging at an EIC

Speaker: Charles Hyde

Slides CEH_Tagging.pdf

13:55 BeAST Detector

The 2015 Long Range Plan for Nuclear Science in the US recommended a high-energy high-luminosity polarized Electron-Ion Collider as the highest priority for new facility construction following the completion of presently ongoing projects. The main physics topics to be explored at this new facility are (i) the polarized sea quark and gluon distributions in the nucleon, (ii) QCD dynamics of the low-x, high density gluon regime, (iii) hadronization in the vacuum and the nuclear medium. One of the considered construction options is the addition of a high-energy polarized electron beam to the existing RHIC hadron machine, converting it into an Electron-Ion Collider (eRHIC). An eRHIC detector, designed to efficiently register and identify deep inelastic electron scattering (DIS) processes in a wide range of center-of-mass energies available with the new collider is one of the key elements of such an upgrade. The current status of the detector design work will be presented, with an emphasis on studies done since the first EIC User Group meeting in Berkeley.

Speaker: Alexander Kiselev

Slides ayk-2016-07-08-anl-ug-meeting.pptx

14:20 Vision for a JLEIC Detector

The emerging physics program at EIC has the potential to revolutionize our understanding of nucleon and nuclei structure and associated dynamics. In order to carry out such a program, EIC detectors must have characteristics that are very different from existing and past collider detectors including those for HERA. This talk will outline how the physics drive the design of the JLEIC interaction region and detector design.

Speaker: Rik Yoshida

Slides JLEIC_Detector_R&D.pptx

14:45 Evolution of sPHENIX into a Day-1 EIC Detector

A new detector, sPHENIX, is being built at the Relativistic Heavy Ion Collider (RHIC) to study the detailed properties of the Quark Gluon Plasma. The sPHENIX detector consists of large acceptance electromagnetic and hadronic calorimetry and tracking detectors at mid rapidity built around the superconducting solenoid acquired from the decommissioned BaBar experiment at SLAC. The detector is being designed to have space available to instrument the forward direction, which is needed to fully realize the physics potential of polarized proton-proton and proton-nucleus collisions. GEM trackers, electromagnetic and hadronic calorimetry, and roman pot detectors are envisioned. Motivations include measurements of jet asymmetries in jet production (both inter- and intra-jet), Drell-Yan asymmetries, and studies of cold nuclear matter. The detector could further evolve into a day-1 EIC detector at RHIC. The magnet and detectors components could also form the basis of an EIC detector at Jefferson Lab. In this EIC detector concept, the sPHENIX detector is utilized as the foundation and additional calorimeters, tracking and particle identification systems are added to deliver a comprehensive physics program. In this talk, we will review the envisioned evolution from sPHENIX to and EIC detector and discuss recent updates on this detector concept and its physics capabilities.

Speaker: Kenneth Barish

Slides sPHENIX_EICUG_Barish.pdf

13:30 → 15:10 Nuclear Structure at Large and Small x (Theory)

13:30 Azimuthal Anisotropy in Deep Inelastic Scattering Dijet Production at High Energy

In this talk I will discuss the distribution of linearly polarized gluons of a dense target at small x in McLerran-Venugopalan model and by solving the Balitsky–Jalilian-Marian–Iancu–McLerran–Weigert–Leonidov–Kovner rapidity evolution equations. The solution shows a sizable amplitude of ∼cos2ϕ azimuthal asymmetries in deep inelastic scattering dijet production at high energies. I will also talk about the first correction to the quadrupole operator in high-energy QCD beyond the TMD limit of Weizsaecker-Williams and linearly polarized gluon distributions. The Correction produces a ~ cos 4 phi angular dependence which is suppressed by one additional power of the dijet transverse momentum scale (squared) P^2.

Speaker: Vladimir Skokov

Slides Skokov.pdf

13:55 Rapidity factorization approach and EIC

Rapidity factorization is a theoretical approach which allows us to study high-energy scattering reactions in a wide range of kinematic variables. This is especially important for the future Electron Ion Collider (EIC) which will give access to much smaller values of $x$, than the range covered by the present fixed-target experiments. I’ll present an essential introduction into the method and show how it can be implemented in particle production at EIC. I’ll show particular results for evolution of gluon TMD distributions valid for different values of Bjorken $x$ and transverse momenta.

Speaker: Andrey Tarasov

Slides Tarasov.pdf

14:20 Quark Helicity at Small x

Traditional small-x evolution, given by the BFKL / BK / JIMWLK evolution equations, describes the growth of unpolarized parton distributions with increasing energy or decreasing x. Polarized distributions, such as the quark helicity, are governed by very different evolution equations with much more intricate structure. Early work suggested that the double-logarithmic evolution of the quark helicity could result in a substantial growth of quark polarization at small x, leading to an important unmeasured contribution to the total proton spin. In recent work, we have formulated helicity evolution in the modern s-channel CGC formalism, deriving evolution equations which include nonlinear multiple scattering. Solving these equations remains challenging, but preliminary numerical work suggests a dependence on the borderline between marginal growth and marginal suppression at small x. We further comment on the differences between our work and prior results, and we discuss possible effects of the nonlinear terms.

Speaker: Matt Sievert

Slides Sievert.pdf

14:45 Nuclear Structure at Large x with an EIC

Speaker: Rolf Ent

Slides Ent.pdf Ent.pptx

15:10 → 15:40 Coffee

15:40 → 18:00 Building on Lessons Learned (Phenomenology)

15:40 ABMP16 PDFs

Speaker: Sergei Alekhin

Slides alekhin.pdf

16:05 What we have learned about Nuclear PDFs at the LHC

Nuclear PDFs are wonderful laboratories for cold QCD. They also provide an essential initial condition for understanding the evolution of the hot quark gluon matter produced in heavy ion collisions. Starting in November 2010 the ALICE, ATLAS and CMS experiments began studying lead-lead, proton-lead collisions and photon-lead collisions. In 2015 LHCb added its unique capabilities at high rapidity and a gas jet target to the effort to understand the high energy limit of QCD. The four experiments are now probing nuclear PDFs down to x values of 10^-5. This talk will review what the proton-lead and photon-lead data have taught us and discuss their complementarity to future EIC measurements.

Speaker: Michael Murray

Slides MurrayEICLhcPdfs.pdf

16:30 Experience from HERA and LHC on diffraction towards the EIC

We will discuss briefly the main results on diffraction at HERA related to the Pomeron structure in view of the recent and potential results at the LHC.

Speaker: Christophe Royon

Slides eic2016.pdf

16:55 Unique opportunities to measure proton elastic form factors at EIC

A colliding beam experiment on proton elastic form factors opens up interesting kinematical regions not easily accessible in fixed target experiments. In the talk, I will discuss the opportunities from a standard 180 degree setup, especially with regard to the proton radius and form factor ratio puzzles. Further, I will present the possibilities of a non-standard setup in which the beams do not collide head on.

Speaker: Jan Bernauer

Slides p_ff.pdf

17:20 Extra time for running late + discussions

15:40 → 18:00 Jets and Novel Probes (Experiment)

15:40 Jets at medium energies

Jet production in electron-proton(ion) scattering at EIC provides an important testing ground for Quantum Chromodynamics. This talk will mostly be focused on low/medium energy jets as the region of most relevance for jets quenching, energy loss and hadronization mechanism. Also a number of interesting studies which could be done with jets, produced in ep(eA) collisions at EIC, will be shown. As will be shown, how adding jets data could help to improve PDF uncertainties (especially for gluons ), as well as a determination of the strong coupling.

Speaker: Yulia Furletova

Slides Furletova.pdf

16:05 Jet Physics at an EIC

The systematic study of jet observables at an EIC and their usefulness as a physics probe is still in the early stages. This talk will summarize several ongoing jet studies, including the ability to differentiate jets arising from quarks or from gluons, the particle content of jets with a focus on the necessity of a hadronic calorimeter, and the use of di-jets in g_1 measurements. Future studies will also be discussed.

Speaker: Brian Page

Slides Page.pdf Page.pptx

16:30 Studying photon structure at EIC

A future Electron-Ion Collider (EIC) facility will deliver luminosities of 10^33 − 10^34 cm^−2 s^−1 for collisions of polarized electrons and protons and heavy ions over a wide range of center-of-mass energies (40 GeV to 145 GeV) [1, 2]. One of its promising physics programs is to study the partonic structure of quasi-real photons. Measuring di-jets in photoproduction events, one can effectively access the underlying parton dynamics of the photons through the selection of the resolved photon processes [3, 4]. In this talk, we discuss the feasibility to measure the di-jets cross section as a function of jet transverse momentum and to tag resolved photon processes at an EIC. First studies show that parton distributions in the photon can be well studied at an EIC. The possibility to distinguish jets originating from photons and those from protons is discussed.

Speaker: Xiaoxuan Chu

Slides Chu.pdf Chu.pptx

16:55 The Electro-Magnetic probes at EIC

The Electro-Magnetic probes have been widely used to study the fundamental properties of hot, dense medium created in heavy ion collisions. Quarkonia through dileptonic decays have been an indicator of the de-confinement while the dileptons radiated from the hot, dense medium have been used to study Chiral Symmetry Restoration, the temperature, and lifetime of the medium. I will briefly review a few interesting observables in heavy ion collisions and present a most-recent STAR result on J/psi production through its dileptonic decay in the very low transverse momentum region (pT<0.2 GeV/c) in peripheral and mid-peripheral Au+Au collisions. The results seem to be consistent with the coherent photon-pomeron production. However,It is unclear how these produced J/psi are affected by the cold and hot QCD matter created in peripheral and mid-peripheral Au+Au collisions. Multiplicity and system size dependences of the very low pT J/psi production at EIC might further our understanding of the cold nuclear matter effect on the J/psi production.

Speaker: Lijuan Ruan

Slides Ruan.pdf

17:20 Electroweak physics at the EIC

We discuss measurements of parity violating asymmetries in the DIS region at an EIC with high luminosity. With $\gamma Z$ interference in the electroweak processes, the parity violating asymmetries are associated with a new series of structure functions, $F_1^{\gamma Z}$ , $F_3^{\gamma Z}$ , $g_1^{\gamma Z}$ , $g_5^{\gamma Z}$ , which provide unique, yet unmeasured, combinations of unpolarized/polarized parton distribution functions. We will present the projections of these structure functions from electron-proton collisions at future EIC with different beam energy configurations considering QED, QCD radiative corrections as well as corrections of detector smearing. We will also present the weak mixing angle $\sin^2 (\theta_W)$ study at much higher $Q^2$ range than fixed target measurements using electron-deuteron collisions at an EIC.

Speaker: Yuxiang Zhao

Slides Electroweak_physics_at_the_EIC_YuxiangZhao.pptx

15:40 → 18:00 Nucleon Structure and Interactions (Theory)

15:40 Opportunities for studying GPDs at the EIC

Speaker: Daria Sokhan

Slides Sokhan.pdf

16:05 GPDs and the PARTON software project

Generalised Parton Distributions (GPDs) has been introduced in the 1990's and have been studied both experimentally and theoretically since then. If the general framework of the field is now well established, the GPDs themselves are still hardly known, since they are hard to extract from experimental data. On the other hand several phenomenological models have been developed, and QCD-connected computations in the continuum are planned for the forthcoming years. After a presentation of the status of the GPDs field, I will introduced the PARTON software project, dedicated to GPDs, and thought to allow both experimental and theoretical studies of GPDs.

Speaker: Cédric Mezrag

Slides Mezrag_GPD.pdf

16:30 Exploring nucleon-nucleon interactions in QCD with EIC

The talk will cover: (a) a unified physics narrative of EIC eA measurements at large, intermediate, and small x under the aspect of exploring the QCD origin/structure of NN interactions; (b) EIC measurements probing the charge/flavor decomposition of the nuclear modifications of quarks/antiquarks at x ~ 0.1 with SIDIS and their connection to NN interactions; (c) some comments on the collective regime at small x.

Speaker: Christian Weiss

Slides Weiss.pdf

16:55 Bound nucleon structure studies with an EIC

Results from recent experiments show that short-range interactions between nucleon in nuclei form correlated, high-momentum, neutron-proton pairs. These pairs are due to the dominance of the tensor part of the nucleon-nucleon interaction at short distances dominate the momentum distribution of nucleons above the Fermi momentum of the nucleus. Recent works have shown that the existence and nature of SRC pairs has wide ranging implications for atomic, nuclear and astro physics, including neutrino-nucleus scattering, neutrino less double better decay, the EMC effect, the NuTeV anomaly, the nuclear symmetry energy and neutron stars structure and more. In this talk I will present the possibility of studying SRC pairs, and their partonic structure, at an EIC, using the method of spectator tagging in Quasi-elastic and Deep-Inelastic kinematics.

Speaker: Or Hen

Slides Hen.pdf

18:30 → 19:00 Bus leaves for dinner

Bus to dinner at Meson Sabika.

19:00 → 21:00 Dinner at Meson Sabika

Saturday, 9 July

09:00 → 10:15 Morning

09:00 EIC Detector R&D

Speaker: Thomas Ullrich

Slides EIC_RD_Talk_ullrich.pdf

09:45 Lessons learned from HERA

Speaker: Dr Jose Repond (Argonne National Laboratory)

Slides EIC_Lessons_ANL_Jul_2016.pptx

10:15 → 10:45 Coffee

10:45 → 12:15 Parallel Summary

Session chair: Elke Aschenauer

10:45 Novel Observables - Building on Lessons Learned

Speaker: Ian Cloet

Slides cloet_eic.pdf

11:15 Novel Technical Advancements - Jets and Novel Probes

Speaker: Salvatore Fazio

Slides Fazio_Summary.pdf Fazio_Summary.pptx

11:45 Nuclear Structure at Large and Small x - Nucleon Structure and Interactions

Speaker: Matt Sievert

Slides Sievert_Parallel_Summary.pdf

12:15 → 13:30 Lunch

13:30 → 15:00 Closing

Session chair: Barbara Jacak

13:30 Future EICUG meeting

13:50 Joint CTEQ Meeting and POETIC 7

Bernd Surrow Joint CTEQ Meeting and POETIC 7 (7th International Conference on Physics Opportunities at an ElecTron-Ion-Collider) at Temple University on November 14-18, 2016

14:05 NAS planning summary and EICUG role

Abhay Deshpande, and Bob McKeown

Speaker: Prof. Abhay Deshpande (Stony Brook University)

15:00 → 15:05 Adjourn