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
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.
© SIF, Springer-Verlag Berlin Heidelberg, 2013