Observation of Beam Spin Asymmetries in the Process $e p \rightarrow e π^{+}π^{-}X$ with CLAS12
Creators: name: Hayward, T. B.
name: Dilks, C.
name: Vossen, A.
name: Avakian, H.
name: Adhikari, S.
name: Angelini, G.
name: Arratia, M.
name: Atac, H.
name: Gayoso, C. Ayerbe
name: Baltzell, N. A.
name: Barion, L.
name: Battaglieri, M.
name: Bedlinskiy, I.
name: Benmokhtar, F.
name: Bianconi, A.
name: Biselli, A. S.
name: Bondì, M.
name: Bossù, F.
name: Boiarinov, S.
name: Briscoe, W. J.
name: Brooks, W. K.
name: Bulumulla, D.
name: Burkert, V. D.
name: Carman, D. S.
name: Carvajal, J. C.
name: Celentano, A.
name: Chatagnon, P.
name: Chetry, T.
name: Ciullo, G.
name: Clary, B. A.
name: Cole, P. L.
name: Contalbrigo, M.
name: Costantini, G.
name: Crede, V.
name: D'Angelo, A.
name: Dashyan, N.
name: De Vita, R.
name: Defurne, M.
name: Deur, A.
name: Diehl, S.
name: Djalali, C.
name: Dupre, R.
name: Dugger, M.
name: Egiyan, H.
name: Ehrhart, M.
name: Alaoui, A. El
name: Fassi, L. El
name: Elouadrhiri, L.
name: Fegan, S.
name: Filippi, A.
name: Forest, T. A.
name: Gavalian, G.
name: Gilfoyle, G. P.
name: Girod, F. X.
name: Glazier, D. I.
name: Golubenko, A. A.
name: Gothe, R. W.
name: Gotra, Y.
name: Griffioen, K. A.
name: Guidal, M.
name: Hafidi, K.
name: Hakobyan, H.
name: Hattawy, M.
name: Hauenstein, F.
name: Hicks, K.
name: Hobart, A.
name: Holtrop, M.
name: Ireland, D. G.
name: Isupov, E. L.
name: Jo, H. S.
name: Joo, K.
name: Joosten, S.
name: Keller, D.
name: Khachatryan, M.
name: Khanal, A.
name: Kim, A.
name: Kim, W.
name: Kripko, A.
name: Kubarovsky, V.
name: Kuhn, S. E.
name: Lanza, L.
name: Leali, M.
name: Lee, S.
name: Lenisa, P.
name: Livingston, K.
name: MacGregor, I. J. D.
name: Marchand, D.
name: Markov, N.
name: Marsicano, L.
name: Mascagna, V.
name: McKinnon, B.
name: Meziani, Z. E.
name: Mirazita, M.
name: Mokeev, V.
name: Movsisyan, A
name: Camacho, C. Munoz
name: Nadel-Turonski, P.
name: Naidoo, P.
name: Nanda, S.
name: Neupane, K.
name: Niccolai, S.
name: Niculescu, G.
name: O'Connell, T. R.
name: Osipenko, M.
name: Paolone, M.
name: Pappalardo, L. L.
name: Paremuzyan, R.
name: Pasyuk, E.
name: Phelps, W.
name: Pogorelko, O.
name: Prok, Y.
name: Raue, B. A.
name: Ripani, M.
name: Ritman, J.
name: Rizzo, A.
name: Rossi, P.
name: Rowley, J.
name: Sabatié, F.
name: Salgado, C.
name: Schmidt, A.
name: Segarra, E. P.
name: Sharabian, Y. G.
name: Shrestha, U.
name: Sokhan, D.
name: Soto, O.
name: Sparveris, N.
name: Stepanyan, S.
name: Strakovsky, I. I.
name: Strauch, S.
name: Thornton, A.
name: Tyler, N.
name: Tyson, R.
name: Ungaro, M.
name: Venturelli, L.
name: Voskanyan, H.
name: Voutier, E.
name: Watts, D. P.
name: Wei, K.
name: Wei, X.
name: Wood, M. H.
name: Yale, B.
name: Zachariou, N.
name: Zhang, J.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: The observation of beam spin asymmetries in two-pion production in semi-inclusive deep inelastic scattering off an unpolarized proton target is reported. The data presented here were taken in the fall of 2018 with the CLAS12 spectrometer using a 10.6 GeV longitudinally spin-polarized electron beam delivered by CEBAF at JLab. The measured asymmetries provide the first opportunity to extract the parton distribution function $e(x)$, which provides information about the interaction between gluons and quarks, in a collinear framework that offers cleaner access than previous measurements. The asymmetries also constitute the first ever signal sensitive to the helicity-dependent two-pion fragmentation function $G_1^\perp$. A clear sign change is observed around the $ρ$ mass that appears in model calculations and is indicative of the dependence of the produced pions on the helicity of the fragmenting quark.
description: 6 pages, 5 figures