@article{fa6a6b9943f743af8aeddb89eaede84d,
title = "Exclusive photoproduction of π0 up to large values of Mandelstam variables s, t, and u with CLAS",
abstract = "Exclusive photoproduction cross sections have been measured for the process γp→pπ0[e+e-(γ)] with the Dalitz decay final state using tagged photon energies in the range of Eγ=1.275-5.425 GeV. The complete angular distribution of the final state π0, for the entire photon energy range up to large values of t and u, has been measured for the first time. The data obtained show that the cross section dσ/dt, at mid to large angles, decreases with energy as s-6.89±0.26. This is in agreement with the perturbative QCD quark counting rule prediction of s-7. Paradoxically, the size of angular distribution of measured cross sections is greatly underestimated by the QCD-based generalized parton distribution mechanism at highest available invariant energy s=11GeV2. At the same time, the Regge-exchange-based models for π0 photoproduction are more consistent with experimental data.",
author = "{CLAS Collaboration} and Kunkel, {M. C.} and Amaryan, {M. J.} and Strakovsky, {I. I.} and J. Ritman and Goldstein, {G. R.} and Adhikari, {K. P.} and S. Adhikari and H. Avakian and J. Ball and I. Balossino and L. Barion and M. Battaglieri and V. Batourine and I. Bedlinskiy and Biselli, {A. S.} and S. Boiarinov and Briscoe, {W. J.} and Brooks, {W. K.} and S. B{\"u}ltmann and Burkert, {V. D.} and F. Cao and Carman, {D. S.} and A. Celentano and G. Charles and T. Chetry and G. Ciullo and L. Clark and Cole, {P. L.} and M. Contalbrigo and O. Cortes and V. Crede and A. D'Angelo and N. Dashyan and {De Vita}, R. and {De Sanctis}, E. and Degtyarenko, {P. V.} and M. Defurne and A. Deur and C. Djalali and Michael Dugger and R. Dupre and H. Egiyan and {El Alaoui}, A. and {El Fassi}, L. and L. Elouadrhiri and P. Eugenio and G. Fedotov and R. Fersch and A. Filippi and Barry Ritchie",
note = "Funding Information: We thank Stanley Brodsky, Alexander Donnachie, Peter Kroll, Vincent Mathieu, and Anatoly Radyushkin for discussions of our measurements. We would like to acknowledge the outstanding efforts of the staff of the Accelerator and the Physics Divisions at Jefferson Lab that made the experiment possible. This work was supported in part by the Italian Istituto Nazionale di Fisica Nucleare, the French Centre National de la Recherche Scientifique and Commissariat {\`a} l'Energie Atomique, the United Kingdom's Science and Technology Facilities Council (STFC), the US DOE and NSF, and the National Research Foundation of Korea. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Contract No. DE-AC05-06OR23177. Funding Information: This work was supported in part by the Italian Istituto Nazionale di Fisica Nucleare, the French Centre National de la Recherche Scientifique and Commissariat l'Energie Atomique, the United Kingdom's Science and Technology Facilities Council (STFC), the US DOE and NSF, and the National Research Foundation of Korea. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Contract No. DE-AC05-06OR23177. Publisher Copyright: {\textcopyright} 2018 authors. Published by the American Physical Society.",
year = "2018",
month = jul,
day = "25",
doi = "10.1103/PhysRevC.98.015207",
language = "English (US)",
volume = "98",
journal = "Physical Review C",
issn = "2469-9985",
publisher = "American Physical Society",
number = "1",
}