Measurement of the two-photon exchange contribution to the elastic e(±)p scattering cross sections at the VEPP-3 storage ring.
The ratio of the elastic e(+)p to e(-)p scattering cross sections has been measured precisely, allowing the determination of the two-photon exchange contribution to these processes. This neglected contribution is believed to be the cause of the discrepancy between the Rosenbluth and polarization transfer methods of measuring the proton electromagnetic form factors. The experiment was performed at the VEPP-3 storage ring at beam energies of 1.6 and 1.0 GeV and at lepton scattering angles between 15° and 105°. The data obtained show evidence of a significant two-photon exchange effect. The results are compared with several theoretical predictions.
Budker Institute of Nuclear Physics, 630090 Novosibirsk, Russia.
I A
IA
Rachek
Argonne National Laboratory, Argonne, Illinois 60439, USA.
J
J
Arrington
Budker Institute of Nuclear Physics, 630090 Novosibirsk, Russia and Novosibirsk State University, 630090 Novosibirsk, Russia.
V F
VF
Dmitriev
Tomsk Polytechnic University, 634050 Tomsk, Russia.
V V
VV
Gauzshtein
Budker Institute of Nuclear Physics, 630090 Novosibirsk, Russia and Novosibirsk State University, 630090 Novosibirsk, Russia.
R E
RE
Gerasimov
Budker Institute of Nuclear Physics, 630090 Novosibirsk, Russia.
A V
AV
Gramolin
Argonne National Laboratory, Argonne, Illinois 60439, USA.
R J
RJ
Holt
Budker Institute of Nuclear Physics, 630090 Novosibirsk, Russia.
V V
VV
Kaminskiy
Budker Institute of Nuclear Physics, 630090 Novosibirsk, Russia.
B A
BA
Lazarenko
Budker Institute of Nuclear Physics, 630090 Novosibirsk, Russia.
S I
SI
Mishnev
Budker Institute of Nuclear Physics, 630090 Novosibirsk, Russia and Novosibirsk State University, 630090 Novosibirsk, Russia.
N Yu
NY
Muchnoi
Budker Institute of Nuclear Physics, 630090 Novosibirsk, Russia.
V V
VV
Neufeld
Budker Institute of Nuclear Physics, 630090 Novosibirsk, Russia.
D M
DM
Nikolenko
Budker Institute of Nuclear Physics, 630090 Novosibirsk, Russia.
R Sh
RSh
Sadykov
Budker Institute of Nuclear Physics, 630090 Novosibirsk, Russia.
Yu V
YV
Shestakov
Tomsk Polytechnic University, 634050 Tomsk, Russia.
V N
VN
Stibunov
Budker Institute of Nuclear Physics, 630090 Novosibirsk, Russia and Novosibirsk State University, 630090 Novosibirsk, Russia.
D K
DK
Toporkov
Nikhef, 1098 XG Amsterdam, Netherlands.
H
H
de Vries
Budker Institute of Nuclear Physics, 630090 Novosibirsk, Russia.
S A
SA
Zevakov
Budker Institute of Nuclear Physics, 630090 Novosibirsk, Russia and Novosibirsk State University, 630090 Novosibirsk, Russia.
V N
VN
Zhilich