Eur. Phys. J. A (2011) 47: 35
https://doi.org/10.1140/epja/i2011-11035-2

Special Article - Tools for Experiment and Theory

Transverse-momentum-dependent parton distribution/fragmentation functions at an electron-ion collider

¹ Università di Torino and INFN, Sezione di Torino, I-10125, Torino, Italy
² Thomas Jefferson National Accelerator Facility, 12000 Jefferson Avenue, 23606, Newport News, VA, USA
³ KVI, University of Groningen, NL-9747, AA Groningen, The Netherlands
⁴ Dipartimento di Fisica, Università degli Studi di Trieste, and INFN, Sezione di Trieste, 34127, Trieste, Italy
⁵ New Mexico State University, 88003, Las Cruces, NM, USA
⁶ INFN, Sezione Roma 1, Gruppo Sanità and Physics Laboratory, Istituto Superiore di Sanità, 00161, Roma, Italy
⁷ INFN, Sezione di Ferrara and Dipartimento di Fisica, Università di Ferrara, 44100, Ferrara, Italy
⁸ University of Virginia, 22901, Charlottesville, VA, USA
⁹ Mississippi State University, 39762, Starkeville, MS, USA
¹⁰ Penn State-Berks, 19610, Reading, PA, USA
¹¹ Triangle Universities Nuclear Laboratory and Department of Physics, Duke University, 27708, Durham, NC, USA
¹² INFN, Laboratori Nazionali di Frascati, 00044, Frascati, Italy
¹³ Massachusetts Institute of Technology, 02139, Cambridge, MA, USA
¹⁴ RIKEN BNL Research Center, Brookhaven National Laboratory, 11973, Upton, NY, USA
¹⁵ Hampton University, 23668, Hampton, VA, USA
¹⁶ School of Physics, Shandong University, 250100, Jinan, Shandong, China
¹⁷ Physics Division, Los Alamos National Laboratory, 87545, Los Alamos, NM, USA
¹⁸ University of Illinois, 61801, Urbana, IL, USA
¹⁹ California Institute of Technology, 91125, Pasadena, CA, USA
²⁰ Temple University, 19122, Philidalphia, PA, USA
²¹ Physics Department, Brookhaven National Laboratory, 11973, Upton, NY, USA
²² University of Connecticut, 06269, Storrs, CT, USA
²³ Tsinghua University, 10084, Beijing, China
²⁴ Lawrence Berkeley National Laboratory, Berkeley, CA, USA
²⁵ Physics Division, Argonne National Laboratory, 60439, Argonne, IL, USA

^* e-mail: gao@tunl.duke.edu

Received: 30 January 2011
Accepted: 3 February 2011
Published online: 11 March 2011

Abstract

We present a summary of a recent workshop held at Duke University on Partonic Transverse Momentum in Hadrons: Quark Spin-Orbit Correlations and Quark-Gluon Interactions. The transverse-momentum-dependent parton distribution functions (TMDs), parton-to-hadron fragmentation functions, and multi-parton correlation functions, were discussed extensively at the Duke workshop. In this paper, we summarize first the theoretical issues concerning the study of partonic structure of hadrons at a future electron-ion collider (EIC) with emphasis on the TMDs. We then present simulation results on experimental studies of TMDs through measurements of single-spin asymmetries (SSA) from semi-inclusive deep inelastic scattering (SIDIS) processes with an EIC, and discuss the requirement of the detector for SIDIS measurements. The dynamics of parton correlations in the nucleon is further explored via a study of SSA in D ( production at large transverse momenta with the aim of accessing the unexplored tri-gluon correlation functions. The workshop participants identified the SSA measurements in SIDIS as a golden program to study TMDs in both the sea and valence quark regions and to study the role of gluons, with the Sivers asymmetry measurements as examples. Such measurements will lead to major advancement in our understanding of TMDs in the valence quark region, and more importantly also allow for the investigation of TMDs in the unexplored sea quark region along with a study of their evolution.