Measurements of the proton's spin structure in experiments scattering a polarized electron beam off polarized protons in regions of low momentum transfer squared test predictions from chiral effective field theory of the strong interaction.Measuring the spin structure of protons and neutrons tests our understanding of how they arise from quarks and gluons, the fundamental building blocks of nuclear matter. At long distances, the coupling constant of the strong interaction becomes large, requiring non-perturbative methods to calculate quantum chromodynamics processes, such as lattice gauge theory or effective field theories. Here we report proton spin structure measurements from scattering a polarized electron beam off polarized protons. The spin-dependent cross-sections were measured at large distances, corresponding to the region of low momentum transfer squared between 0.012 and 1.0 GeV2. This kinematic range provides unique tests of chiral effective field theory predictions. Our results show that a complete description of the nucleon spin remains elusive, and call for further theoretical works, for example, in lattice quantum chromodynamics. Finally, our data extrapolated to the photon point agree with the Gerasimov-Drell-Hearn sum rule, a fundamental prediction of quantum field theory that relates the anomalous magnetic moment of the proton to its integrated spin-dependent cross-sections.

Zheng, X., Deur, A., Kang, H., Kuhn, S.e., Ripani, M., Zhang, J., et al. (2021). Measurement of the proton spin structure at long distances. NATURE PHYSICS, 17(6), 736-741 [10.1038/s41567-021-01198-z].

Measurement of the proton spin structure at long distances

D'Angelo A.
Membro del Collaboration Group
;
Lanza L.
Membro del Collaboration Group
;
Rizzo A.
Membro del Collaboration Group
;
2021-04-12

Abstract

Measurements of the proton's spin structure in experiments scattering a polarized electron beam off polarized protons in regions of low momentum transfer squared test predictions from chiral effective field theory of the strong interaction.Measuring the spin structure of protons and neutrons tests our understanding of how they arise from quarks and gluons, the fundamental building blocks of nuclear matter. At long distances, the coupling constant of the strong interaction becomes large, requiring non-perturbative methods to calculate quantum chromodynamics processes, such as lattice gauge theory or effective field theories. Here we report proton spin structure measurements from scattering a polarized electron beam off polarized protons. The spin-dependent cross-sections were measured at large distances, corresponding to the region of low momentum transfer squared between 0.012 and 1.0 GeV2. This kinematic range provides unique tests of chiral effective field theory predictions. Our results show that a complete description of the nucleon spin remains elusive, and call for further theoretical works, for example, in lattice quantum chromodynamics. Finally, our data extrapolated to the photon point agree with the Gerasimov-Drell-Hearn sum rule, a fundamental prediction of quantum field theory that relates the anomalous magnetic moment of the proton to its integrated spin-dependent cross-sections.
12-apr-2021
Pubblicato
Rilevanza internazionale
Articolo
Esperti anonimi
Settore FIS/04 - FISICA NUCLEARE E SUBNUCLEARE
English
Con Impact Factor ISI
virtual compton-scattering; chiral perturbation-theory; sum-rule; polarized target; nucleon; moments; polarizabilities; evolution; order; Physics
CLAS Collaboration
https://www.nature.com/articles/s41567-021-01198-z
Zheng, X., Deur, A., Kang, H., Kuhn, S.e., Ripani, M., Zhang, J., et al. (2021). Measurement of the proton spin structure at long distances. NATURE PHYSICS, 17(6), 736-741 [10.1038/s41567-021-01198-z].
Zheng, X; Deur, A; Kang, H; Kuhn, Se; Ripani, M; Zhang, J; Adhikari, Kp; Adhikari, S; Amaryan, Mj; Atac, H; Avakian, H; Barion, L; Battaglieri, M; Bedlinskiy, I; Benmokhtar, F; Bianconi, A; Biselli, As; Boiarinov, S; Bondi, M; Bossu, F; Bosted, P; Briscoe, Wj; Brock, J; Brooks, Wk; Bulumulla, D; Burkert, Vd; Carlin, C; Carman, Ds; Carvajal, Jc; Celentano, A; Chatagnon, P; Chetry, T; Chen, J-; Choi, S; Ciullo, G; Clark, L; Cole, Pl; Contalbrigo, M; Crede, V; D'Angelo, A; Dashyan, N; De Vita, R; Defurne, M; Diehl, S; Djalali, C; Drozdov, Va; Dupre, R; Ehrhart, M; El Alaoui, A; El Fassi, L; Elouadrhiri, L; Eugenio, P; Fedotov, G; Fegan, S; Fersch, R; Filippi, A; Forest, Ta; Ghandilyan, Y; Gilfoyle, Gp; Giovanetti, Kl; Girod, F-; Glazier, Di; Gothe, Rw; Griffioen, Ka; Guidal, M; Guler, N; Guo, L; Hafidi, K; Hakobyan, H; Hattawy, M; Hayward, Tb; Heddle, D; Hicks, K; Hobart, A; Holmstrom, T; Holtrop, M; Ilieva, Y; Ireland, Dg; Isupov, El; Jo, Hs; Joo, K; Joosten, S; Keith, Cd; Keller, D; Khanal, A; Khandaker, M; Kim, Cw; Kim, W; Klein, Fj; Kripko, A; Kubarovsky, V; Lanza, L; Leali, M; Lenisa, P; Livingston, K; Long, E; Macgregor, Ijd; Markov, N; Marsicano, L; Mascagna, V; Mckinnon, B; Meekins, Dg; Mineeva, T; Mirazita, M; Mokeev, V; Mullen, C; Nadel-Turonski, P; Neupane, K; Niccolai, S; Osipenko, M; Ostrovidov, Ai; Paolone, M; Pappalardo, L; Park, K; Pasyuk, E; Phelps, W; Phillips, Sk; Pogorelko, O; Poudel, J; Prok, Y; Raue, Ba; Ritman, J; Rizzo, A; Rosner, G; Rossi, P; Rowley, J; Sabatie, F; Salgado, C; Schmidt, A; Schumacher, Ra; Seely, Ml; Sharabian, Yg; Shrestha, U; Sirca, S; Slifer, K; Sparveris, N; Stepanyan, S; Strakovsky, Ii; Strauch, S; Sulkosky, V; Tyler, N; Ungaro, M; Venturelli, L; Voskanyan, H; Voutier, E; Watts, Dp; Wei, X; Weinstein, Lb; Wood, Mh; Yale, B; Zachariou, N; Zhao, Zw
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/287747
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