PHYSICS LETTERS B
We report on the first measurement of cross sections for exclusive deeply virtual pion electroproduction off the proton, ep -> e'n pi(+), above the resonance region at backward pion center-of-mass angles. The phi(pi)*-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. (C) 2018 The Authors. Published by Elsevier B.V.
Park, K.; Guidal, M.; Gothe, R. W.; Pire, B.; Semenov-Tian-Shansky, K.; Laget, J. -M.; Adhikari, K. P.; Adhikari, S.; Akbar, Z.; Avakian, H.; Ball, J.; Balossino, I.; Baltzell, N. A.; Barion, L.; Battaglieri, M.; Bedlinskiy, I.; Biselli, A. S.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Cao, F. T.; Carman, D. S.; Celentano, A.; Charles, G.; and Chetry, T., "Hard exclusive pion electroproduction at backward angles with CLAS" (2018). PHYSICS LETTERS B. 37. 340-345. 10.1016/j.physletb.2018.03.026