Authors

M. Derrick, Argonne National Laboratory
D. Krakauer, Argonne National Laboratory
S. Magill, Argonne National Laboratory
D. Mikunas, Argonne National Laboratory
B. Musgrave, Argonne National Laboratory
J. R. Okrasiński, Argonne National Laboratory
J. Repond, Argonne National Laboratory
R. Stanek, Argonne National Laboratory
R. L. Talaga, Argonne National Laboratory
H. Zhang, Argonne National Laboratory
M. C.K. Mattingly, Andrews University
F. Anselmo, Alma Mater Studiorum Università di Bologna
P. Antonioli, Alma Mater Studiorum Università di Bologna
G. Bari, Alma Mater Studiorum Università di Bologna
M. Basile, Alma Mater Studiorum Università di Bologna
L. Bellagamba, Alma Mater Studiorum Università di Bologna
D. Boscherini, Alma Mater Studiorum Università di Bologna
A. Bruni, Alma Mater Studiorum Università di Bologna
G. Bruni, Alma Mater Studiorum Università di Bologna
P. Bruni, Alma Mater Studiorum Università di Bologna
G. Cara Romeo, Alma Mater Studiorum Università di Bologna
G. Castellini, Alma Mater Studiorum Università di Bologna
M. Chiarini, Alma Mater Studiorum Università di Bologna
L. Cifarelli, Alma Mater Studiorum Università di Bologna
F. Cindolo, Alma Mater Studiorum Università di Bologna
A. Contin, Alma Mater Studiorum Università di Bologna
M. Corradi, Alma Mater Studiorum Università di Bologna
I. Gialas, Alma Mater Studiorum Università di Bologna
P. Giusti, Alma Mater Studiorum Università di Bologna
G. Iacobucci, Alma Mater Studiorum Università di Bologna
G. Laurenti, Alma Mater Studiorum Università di Bologna
G. Levi, Alma Mater Studiorum Università di Bologna
A. Margotti, Alma Mater Studiorum Università di Bologna

Document Type

Article

Publication Date

1-1-1997

Abstract

The differential cross section dσ/dt for elastic ρ0 photoproduction, γp → ρ0ρ (ρ0 → π+π-), has been measured in ep interactions at HERA. The squared four-momentum exchanged at the proton vertex, t, has been determined directly by measuring the momentum of the scattered proton using the ZEUS Leading Proton Spectrometer (LPS), a large scale system of silicon micro-strip detectors operating close to the HERA proton beam. The LPS allows the measurement of the momentum of high energy protons scattered at small angles with accuracies of 0.4% for the longitudinal momentum and 5 MeV for the transverse momentum. Photoproduction of ρ0 mesons has been investigated in the interval 0.073 < |t| < 0.40 GeV2, for photon virtualities Q2 < 1 GeV2 and photon-proton centre-of-mass energies W between 50 and 100 GeV. In the measured range, the t distribution exhibits an exponential shape with a slope parameter b = 9.8 ± 0.8 (stat.) ± 1.1 (syst.) GeV-2. The use of the LPS eliminates the contamination from events with diffractive dissociation of the proton into low mass states. © Springler-Verlag 1997.

Publication Source (Journal or Book title)

Zeitschrift fur Physik C-Particles and Fields

First Page

253

Last Page

268

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