Hard exclusive pion electroproduction at backward angles with CLAS

K. Park , M. Guidal (1) , W. Gothe , B. Pire (2) , K. Semenov-Tian-Shansky (3) , J. Laget , P. Adhikari , S. Adhikari , Z. Akbar , H. Avakian (4) , J. Ball , I. Balossino (5) , N. Baltzell , L. Barion , M. Battaglieri , I. Bedlinskiy , S. Biselli , J. Briscoe , W. Brooks , D. Burkert , F. Cao , S. Carman , A. Celentano (6) , G. Charles , T. Chetry , G. Ciullo , L. Clark , P. Cole , M. Contalbrigo , V. Crede , A. d'Angelo , N. Dashyan , R. de Vita , E. de Sanctis , M. Defurne (7) , A. Deur , C. Djalali (1) , R. Dupre (1) , H. Egiyan , A. El Alaoui , L. El Fassi , L. Elouadrhiri , P. Eugenio , G. Fedotov , R. Fersch , A. Filippi (5) , M. Garçon (8) , Y. Ghandilyan , P. Gilfoyle , X. Girod (7) , E. Golovatch , A. Griffioen , L. Guo (9) , K. Hafidi , H. Hakobyan , C. Hanretty , N. Harrison , M. Hattawy (1) , D. Heddle , K. Hicks , M. Holtrop , E. Hyde (10) , Y. Ilieva , D. Ireland , S. Ishkhanov , E. Isupov , D. Jenkins , S. Johnston (11) , K. Joo , M. Kabir (12) , D. Keller , G. Khachatryan , M. Khachatryan , M. Khandaker (13) , W. Kim , J. Klein (14) , V. Kubarovsky , Estelle Kuhn , L. Lanza , K. Livingston , J. Macgregor , N. Markov , B. Mckinnon , M. Mirazita (13) , V. Mokeev (1) , R.A. Montgomery , C. Munoz Camacho , P. Nadel-Turonski , S. Niccolai (1) , G. Niculescu , M. Osipenko , M. Paolone , R. Paremuzyan (1) , E. Pasyuk , W. Phelps , O. Pogorelko , J. Poudel , J. Price , Y. Prok (10) , D. Protopopescu , M. Ripani , A. Rizzo (15) , P. Rossi , F. Sabatié (7) , C. Salgado , R.A. Schumacher , Y. Sharabian , Iu. Skorodumina , D. Smith (16) , D. Sokhan (1) , N. Sparveris , S. Stepanyan , I.I. Strakovsky , S. Strauch , M. Taiuti , J. Tan , M. Ungaro , H. Voskanyan , E. Voutier , X. Wei (17) , N. Zachariou , J. Zhang (18)

1 IPNO - Institut de Physique Nucléaire d'Orsay
2 CPHT - Centre de Physique Théorique [Palaiseau]
3 IFPA - Interactions Fondamentales en Physique et en Astrophysique
4 Jefferson Lab - Thomas Jefferson National Accelerator Facility
5 INFN, Sezione di Torino - Istituto Nazionale di Fisica Nucleare, Sezione di Torino
6 University of Ca’ Foscari [Venice, Italy]
7 DPHN - Département de Physique Nucléaire (ex SPhN)
8 ETH Zürich - Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich]
9 Clemson University
10 ODU - Old Dominion University [Norfolk]
11 CSIRO Astronomy and Space Science
12 MIT - Massachusetts Institute of Technology
13 DAPNIA - Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée
14 LAGEP - Laboratoire d'automatique et de génie des procédés
15 Polito - Politecnico di Torino = Polytechnic of Turin
16 CENBG - Centre d'Etudes Nucléaires de Bordeaux Gradignan
17 School of Mechanical Engineering
18 School of Geography

We report on the first measurement of cross sections for exclusive deeply virtual pion electroproduction off the proton, ep → e′nπ+, above the resonance region at backward pion center-of-mass angles. The φ -dependent cross sections were measured, from which we extracted three combinations of structure functions of the proton. Our results are compatible with calculations based on nucleon-to-pion transition distribution amplitudes (TDAs). These non-perturbative objects are defined as matrix elements of three- quark-light-cone-operators and characterize partonic correlations with a particular emphasis on baryon charge distribution inside a nucleon.

Domaines: Physique Nucléaire Expérimentale [nucl-ex]; Physique des Hautes Energies - Expérience [hep-ex]; Physique des Hautes Energies - Phénoménologie [hep-ph]

K. Park, M. Guidal, W. Gothe, B. Pire, K. Semenov-Tian-Shansky, et al.. Hard exclusive pion electroproduction at backward angles with CLAS. Physics Letters B, 2018, 780, pp.340 - 345. ⟨10.1016/j.physletb.2018.03.026⟩. ⟨hal-01754761⟩