Exclusive photoproduction of $π^0$ up to large values of Mandelstam variables $s, t$ and $u$ with CLAS
Creators: name: Kunkel, M. C.
name: 32
name: Amaryan, 18 M. J.
name: 32
name: Strakovsky, I. I.
name: Ritman, 16 J.
name: 3
name: Goldstein, 18 G. R.
name: Adhikari, 43 K. P.
name: Adhikari, 28 S
name: Avakian, 13 H.
name: Ball, 39 J.
name: Balossino, 7 I.
name: Barion, 19 L.
name: Battaglieri, 19 M.
name: Batourine, 21 V.
name: 39
name: Bedlinskiy, 27 I.
name: Biselli, 25 A. S.
name: 11
name: Boiarinov, 5 S.
name: Briscoe, 39 W. J.
name: Brooks, 16 W. K.
name: 40
name: Bueltmann, 39 S.
name: Burkert, 32 V. D.
name: Cao, 39 F.
name: Carman, 9 D. S.
name: Celentano, 39 A.
name: Charles, 21 G.
name: Chetry, 32 T.
name: Ciullo, 31 G.
name: 19
name: Clark, 12 L.
name: Cole, 42 P. L.
name: Contalbrigo, 17 M.
name: Cortes, 19 O.
name: Crede, 17 V.
name: DAngelo, 14 A.
name: 22
name: Dashyan, 35 N.
name: De Vita, 47 R.
name: De Sanctis, 21 E.
name: Degtyarenko, 20 P. V.
name: Defurne, 39 M.
name: Deur, 7 A.
name: Djalali, 39 C.
name: Dugger, 37 M.
name: Dupre, 2 R.
name: Egiyan, 24 H.
name: Alaoui, 39 A. El
name: Fassi, 40 L. El
name: Elouadrhiri, 28 L.
name: Eugenio, 39 P.
name: Fedotov, 14 G.
name: Fersch, 31 R.
name: 8
name: Filippi, 46 A.
name: Fradi, 23 A.
name: Gavalian, 24 G.
name: 39
name: Ghandilyan, 29 Y.
name: Ghosh, 47 S.
name: Gilfoyle, 10 G. P.
name: Giovanetti, 34 K. L.
name: Girod, 26 F. X.
name: Glazier, 39 D. I.
name: Gohn, 42 W.
name: 9
name: Golovatch, E.
name: Gothe, 36 R. W.
name: Griffioen, 37 K. A.
name: Guo, 46 L.
name: 13
name: Guidal, 39 M.
name: Hafidi, 24 K.
name: Hakobyan, 1 H.
name: 40
name: Harrison, 47 N.
name: Hattawy, 39 M.
name: Hicks, 1 K.
name: Holtrop, 31 M.
name: Hyde, 29 C. E.
name: Ireland, 32 D. G.
name: Ishkhanov, 42 B. S.
name: Isupov, 36 E. L.
name: Jenkins, 36 D.
name: Joo, 44 K.
name: Kabir, 9 M. L.
name: Keller, 28 D.
name: Khachatryan, 45 G.
name: Khachatryan, 47 M.
name: Khandaker, 32 M.
name: 30
name: Kim, A.
name: Kim, 9 W.
name: Klein, 27 A.
name: Klein, 32 F.
name: 6
name: Kubarovsky, 16 V.
name: Kuhn, 39 S. E.
name: Laget, 32 J. M.
name: 39
name: Lanza, 7 L.
name: 22
name: Lenisa, 35 P.
name: Lersch, 19 D.
name: Livingston, 18 K.
name: MacGregor, 42 I . J . D.
name: Markov, 42 N.
name: Mbianda, 9 G.
name: McKinnon, 32 B.
name: Mineeva, 42 T.
name: 40
name: Mokeev, 9 V.
name: 39
name: Montgomery, 36 R. A.
name: Movsisyan, 42 A
name: Camacho, 19 C. Munoz
name: Nadel-Turonski, 24 P.
name: Niccolai, 39 S.
name: Niculescu, 24 G.
name: Osipenko, 26 M.
name: Ostrovidov, 21 A. I.
name: Paolone, 14 M.
name: Park, 38 K.
name: 39
name: Pasyuk, 37 E.
name: Payette, 39 D.
name: Phelps, 32 W.
name: 13
name: Pogorelko, 16 O.
name: Poudel, 25 J.
name: Price, 32 J. W.
name: Procureur, 4 S.
name: Prok, 7 Y.
name: 32
name: Protopopescu, 45 D.
name: Ripani, 42 M.
name: Ritchie, 21 B. G.
name: Rizzo, 2 A.
name: 22
name: Rosner, 35 G.
name: Roy, 42 A.
name: Sabatie, 10 F.
name: Salgado, 7 C.
name: Schadmand, 30 S.
name: Schumacher, 18 R. A.
name: Sharabian, 5 Y. G.
name: Skorodumina, 39 Iu.
name: 37
name: Ireland, 36 D. G.
name: Sokhan, 42 D.
name: Sober, 42 D. I.
name: Sparveris, 6 N.
name: Strauch, 38 S.
name: 37
name: Taiuti, 16 M.
name: 21
name: Tan, 15 J. A.
name: Ungaro, 27 M.
name: 39
name: Voskanyan, 33 H.
name: Voutier, 47 E.
name: Watts, 24 D. P.
name: Weinstein, 41 L.
name: Wei, 32 X.
name: Weygand, 39 D. P.
name: Zachariou, 8 N.
name: Zhang, 41 J.
name: 45
name: Zhao32, Z. W.
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Experiment (nucl-ex)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: Exclusive photoproduction cross sections have been measured for the process $γp \rightarrow pπ^0(e^+e^-(γ))$ with the Dalitz decay final state using tagged photon energies in the range of $E_γ = 1.275-5.425$ GeV. The complete angular distribution of the final state $π^0$, 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\pm 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 $s=11$ GeV$^2$. At the same time, the Regge exchange based models for $π^0$ photoproduction are more consistent with experimental data.
description: 7 pages, 6 figures