Eur. Phys. J. A (2013) 49: 16
https://doi.org/10.1140/epja/i2013-13016-9

Regular Article - Experimental Physics

Deep exclusive π⁺ electroproduction off the proton at CLAS

¹ Argonne National Laboratory, 60439, Argonne, Illinois, USA
² Arizona State University, 85287-1504, Tempe, Arizona, USA
³ California State University, Dominguez Hills, 90747, Carson, California, USA
⁴ Canisius College, 14208, Buffalo, New York, USA
⁵ Carnegie Mellon University, 15213, Pittsburgh, Pennsylvania, USA
⁶ Catholic University of America, 20064, Washington, D.C., USA
⁷ CEA, Centre de Saclay, Irfu/Service de Physique Nucléaire, 91191, Gif-sur-Yvette, France
⁸ Christopher Newport University, 23606, Newport News, Virginia, USA
⁹ University of Connecticut, 06269, Storrs, Connecticut, USA
¹⁰ Edinburgh University, EH9 3JZ, Edinburgh, UK
¹¹ Fairfield University, 06824, Fairfield, Connecticut, USA
¹² Florida International University, 33199, Miami, Florida, USA
¹³ Florida State University, 32306, Tallahassee, Florida, USA
¹⁴ Università di Genova, 16146, Genova, Italy
¹⁵ The George Washington University, 20052, Washington, D.C., USA
¹⁶ Idaho State University, 83209, Pocatello, Idaho, USA
¹⁷ INFN, Sezione di Ferrara, 44100, Ferrara, Italy
¹⁸ INFN, Laboratori Nazionali di Frascati, 00044, Frascati, Italy
¹⁹ INFN, Sezione di Genova, 16146, Genova, Italy
²⁰ INFN, Sezione di Roma Tor Vergata, 00133, Rome, Italy
²¹ Institut de Physique Nucléaire ORSAY, Orsay, France
²² Institute of Theoretical and Experimental Physics, 117259, Moscow, Russia
²³ James Madison University, 22807, Harrisonburg, Virginia, USA
²⁴ Kyungpook National University, 702-701, Daegu, Republic of Korea
²⁵ LPSC, Université Joseph Fourier, Grenoble, France
²⁶ University of New Hampshire, 03824-3568, Durham, New Hampshire, USA
²⁷ Norfolk State University, 23504, Norfolk, Virginia, USA
²⁸ Ohio University, 45701, Athens, Ohio, USA
²⁹ Old Dominion University, 23529, Norfolk, Virginia, USA
³⁰ Rensselaer Polytechnic Institute, 12180-3590, Troy, New York, USA
³¹ University of Richmond, 23173, Richmond, Virginia, USA
³² Università di Roma Tor Vergata, 00133, Rome, Italy
³³ Skobeltsyn Nuclear Physics Institute, Skobeltsyn Nuclear Physics Institute, 119899, Moscow, Russia
³⁴ University of South Carolina, 29208, Columbia, South Carolina, USA
³⁵ Thomas Jefferson National Accelerator Facility, 23606, Newport News, Virginia, USA
³⁶ Universidad Técnica Federico Santa María, Casilla 110-V, Valparaíso, Chile
³⁷ University of Glasgow, G12 8QQ, Glasgow, UK
³⁸ Virginia Polytechnic Institute, State University, 24061-0435, Blacksburg, Virginia, USA
³⁹ University of Virginia, 22901, Charlottesville, Virginia, USA
⁴⁰ College of William and Mary, 23187-8795, Williamsburg, Virginia, USA
⁴¹ Yerevan Physics Institute, 375036, Yerevan, Armenia

^* e-mail: parkkj@jlab.org

Received: 11 June 2012
Revised: 7 December 2012
Accepted: 5 January 2013
Published online: 30 January 2013

Abstract

The exclusive electroproduction of π ⁺ above the resonance region was studied using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Laboratory by scattering a 6GeV continuous electron beam off a hydrogen target. The large acceptance and good resolution of CLAS, together with the high luminosity, allowed us to measure the cross section for the γ ^* p → nπ ⁺ process in 140 (Q ², x _B , t) bins: 0.16 < x _B < 0.58, 1.6 GeV² < Q ² < 4.5 GeV² and 0.1 GeV² < −t < 5.3 GeV². For most bins, the statistical accuracy is on the order of a few percent. Differential cross sections are compared to four theoretical models, based either on hadronic or on partonic degrees of freedom. The four models can describe the gross features of the data reasonably well, but differ strongly in their ingredients. In particular, the model based on Generalized Parton Distributions (GPDs) contain the interesting potential to experimentally access transversity GPDs.