Measurement of transverse single-spin asymmetries of $π^0$ and electromagnetic jets at forward rapidity in 200 and 500 GeV transversely polarized proton-proton collisions
Creators: name: STAR Collaboration
name: Adam, J.
name: Adamczyk, L.
name: Adams, J. R.
name: Adkins, J. K.
name: Agakishiev, G.
name: Aggarwal, M. M.
name: Ahammed, Z.
name: Alekseev, I.
name: Anderson, D. M.
name: Aparin, A.
name: Aschenauer, E. C.
name: Ashraf, M. U.
name: Atetalla, F. G.
name: Attri, A.
name: Averichev, G. S.
name: Bairathi, V.
name: Barish, K.
name: Behera, A.
name: Bellwied, R.
name: Bhasin, A.
name: Bielcik, J.
name: Bielcikova, J.
name: Bland, L. C.
name: Bordyuzhin, I. G.
name: Brandenburg, J. D.
name: Brandin, A. V.
name: Butterworth, J.
name: Caines, H.
name: Sánchez, M. Calderón de la Barca
name: Cebra, D.
name: Chakaberia, I.
name: Chaloupka, P.
name: Chan, B. K.
name: Chang, F-H.
name: Chang, Z.
name: Chankova-Bunzarova, N.
name: Chatterjee, A.
name: Chen, D.
name: Chen, J.
name: Chen, J. H.
name: Chen, X.
name: Chen, Z.
name: Cheng, J.
name: Cherney, M.
name: Chevalier, M.
name: Choudhury, S.
name: Christie, W.
name: Chu, X.
name: Crawford, H. J.
name: Csanád, M.
name: Daugherity, M.
name: Dedovich, T. G.
name: Deppner, I. M.
name: Derevschikov, A. A.
name: Didenko, L.
name: Dilks, C.
name: Dong, X.
name: Drachenberg, J. L.
name: Dunlop, J. C.
name: Edmonds, T.
name: Elsey, N.
name: Engelage, J.
name: Eppley, G.
name: Esumi, S.
name: Evdokimov, O.
name: Ewigleben, A.
name: Eyser, O.
name: Fatemi, R.
name: Fazio, S.
name: Federic, P.
name: Fedorisin, J.
name: Feng, C. J.
name: Feng, Y.
name: Filip, P.
name: Finch, E.
name: Fisyak, Y.
name: Francisco, A.
name: Fulek, L.
name: Gagliardi, C. A.
name: Galatyuk, T.
name: Geurts, F.
name: Ghimire, N.
name: Gibson, A.
name: Gopal, K.
name: Gou, X.
name: Grosnick, D.
name: Guryn, W.
name: Hamad, A. I.
name: Hamed, A.
name: Harabasz, S.
name: Harris, J. W.
name: He, S.
name: He, W.
name: He, X. H.
name: He, Y.
name: Heppelmann, S.
name: Heppelmann, S.
name: Herrmann, N.
name: Hoffman, E.
name: Holub, L.
name: Hong, Y.
name: Horvat, S.
name: Hu, Y.
name: Huang, H. Z.
name: Huang, S. L.
name: Huang, T.
name: Huang, X.
name: Humanic, T. J.
name: Huo, P.
name: Igo, G.
name: Isenhower, D.
name: Jacobs, W. W.
name: Jena, C.
name: Jentsch, A.
name: Ji, Y.
name: Jia, J.
name: Jiang, K.
name: Jowzaee, S.
name: Ju, X.
name: Judd, E. G.
name: Kabana, S.
name: Kabir, M. L.
name: Kagamaster, S.
name: Kalinkin, D.
name: Kang, K.
name: Kapukchyan, D.
name: Kauder, K.
name: Ke, H. W.
name: Keane, D.
name: Kechechyan, A.
name: Kelsey, M.
name: Khyzhniak, Y. V.
name: Kikoła, D. P.
name: Kim, C.
name: Kimelman, B.
name: Kincses, D.
name: Kinghorn, T. A.
name: Kisel, I.
name: Kiselev, A.
name: Kocan, M.
name: Kochenda, L.
name: Kosarzewski, L. K.
name: Kramarik, L.
name: Kravtsov, P.
name: Krueger, K.
name: Mudiyanselage, N. Kulathunga
name: Kumar, L.
name: Kumar, S.
name: Elayavalli, R. Kunnawalkam
name: Kwasizur, J. H.
name: Lacey, R.
name: Lan, S.
name: Landgraf, J. M.
name: Lauret, J.
name: Lebedev, A.
name: Lednicky, R.
name: Lee, J. H.
name: Leung, Y. H.
name: Li, C.
name: Li, C.
name: Li, W.
name: Li, W.
name: Li, X.
name: Li, Y.
name: Liang, Y.
name: Licenik, R.
name: Lin, T.
name: Lin, Y.
name: Lisa, M. A.
name: Liu, F.
name: Liu, H.
name: Liu, P.
name: Liu, P.
name: Liu, T.
name: Liu, X.
name: Liu, Y.
name: Liu, Z.
name: Ljubicic, T.
name: Llope, W. J.
name: Longacre, R. S.
name: Lukow, N. S.
name: Luo, S.
name: Luo, X.
name: Ma, G. L.
name: Ma, L.
name: Ma, R.
name: Ma, Y. G.
name: Magdy, N.
name: Majka, R.
name: Mallick, D.
name: Margetis, S.
name: Markert, C.
name: Matis, H. S.
name: Mazer, J. A.
name: Minaev, N. G.
name: Mioduszewski, S.
name: Mohanty, B.
name: Mondal, M. M.
name: Mooney, I.
name: Moravcova, Z.
name: Morozov, D. A.
name: Nagy, M.
name: Nam, J. D.
name: Nasim, Md.
name: Nayak, K.
name: Neff, D.
name: Nelson, J. M.
name: Nemes, D. B.
name: Nie, M.
name: Nigmatkulov, G.
name: Niida, T.
name: Nogach, L. V.
name: Nonaka, T.
name: Nunes, A. S.
name: Odyniec, G.
name: Ogawa, A.
name: Oh, S.
name: Okorokov, V. A.
name: Page, B. S.
name: Pak, R.
name: Pandav, A.
name: Panebratsev, Y.
name: Pawlik, B.
name: Pawlowska, D.
name: Pei, H.
name: Perkins, C.
name: Pinsky, L.
name: Pintér, R. L.
name: Pluta, J.
name: Pokhrel, B. R.
name: Porter, J.
name: Posik, M.
name: Pruthi, N. K.
name: Przybycien, M.
name: Putschke, J.
name: Qiu, H.
name: Quintero, A.
name: Radhakrishnan, S. K.
name: Ramachandran, S.
name: Ray, R. L.
name: Reed, R.
name: Ritter, H. G.
name: Rogachevskiy, O. V.
name: Romero, J. L.
name: Ruan, L.
name: Rusnak, J.
name: Sahoo, N. R.
name: Sako, H.
name: Salur, S.
name: Sandweiss, J.
name: Sato, S.
name: Schmidke, W. B.
name: Schmitz, N.
name: Schweid, B. R.
name: Seck, F.
name: Seger, J.
name: Sergeeva, M.
name: Seto, R.
name: Seyboth, P.
name: Shah, N.
name: Shahaliev, E.
name: Shanmuganathan, P. V.
name: Shao, M.
name: Sheikh, A. I.
name: Shen, W. Q.
name: Shi, S. S.
name: Shi, Y.
name: Shou, Q. Y.
name: Sichtermann, E. P.
name: Sikora, R.
name: Simko, M.
name: Singh, J.
name: Singha, S.
name: Smirnov, N.
name: Solyst, W.
name: Sorensen, P.
name: Spinka, H. M.
name: Srivastava, B.
name: Stanislaus, T. D. S.
name: Stefaniak, M.
name: Stewart, D. J.
name: Strikhanov, M.
name: Stringfellow, B.
name: Suaide, A. A. P.
name: Sumbera, M.
name: Summa, B.
name: Sun, X. M.
name: Sun, X.
name: Sun, Y.
name: Sun, Y.
name: Surrow, B.
name: Svirida, D. N.
name: Szymanski, P.
name: Tang, A. H.
name: Tang, Z.
name: Taranenko, A.
name: Tarnowsky, T.
name: Thomas, J. H.
name: Timmins, A. R.
name: Tlusty, D.
name: Tokarev, M.
name: Tomkiel, C. A.
name: Trentalange, S.
name: Tribble, R. E.
name: Tribedy, P.
name: Tripathy, S. K.
name: Tsai, O. D.
name: Tu, Z.
name: Ullrich, T.
name: Underwood, D. G.
name: Upsal, I.
name: Van Buren, G.
name: Vanek, J.
name: Vasiliev, A. N.
name: Vassiliev, I.
name: Videbæk, F.
name: Vokal, S.
name: Voloshin, S. A.
name: Wang, F.
name: Wang, G.
name: Wang, J. S.
name: Wang, P.
name: Wang, Y.
name: Wang, Y.
name: Wang, Z.
name: Webb, J. C.
name: Weidenkaff, P. C.
name: Wen, L.
name: Westfall, G. D.
name: Wieman, H.
name: Wissink, S. W.
name: Witt, R.
name: Wu, Y.
name: Xiao, Z. G.
name: Xie, G.
name: Xie, W.
name: Xu, H.
name: Xu, N.
name: Xu, Q. H.
name: Xu, Y. F.
name: Xu, Y.
name: Xu, Z.
name: Xu, Z.
name: Yang, C.
name: Yang, Q.
name: Yang, S.
name: Yang, Y.
name: Yang, Z.
name: Ye, Z.
name: Ye, Z.
name: Yi, L.
name: Yip, K.
name: Yu, Y.
name: Zbroszczyk, H.
name: Zha, W.
name: Zhang, C.
name: Zhang, D.
name: Zhang, S.
name: Zhang, S.
name: Zhang, X. P.
name: Zhang, Y.
name: Zhang, Y.
name: Zhang, Z. J.
name: Zhang, Z.
name: Zhang, Z.
name: Zhao, J.
name: Zhong, C.
name: Zhou, C.
name: Zhu, X.
name: Zhu, Z.
name: Zurek, M.
name: Zyzak, M.
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: The STAR Collaboration reports measurements of the transverse single-spin asymmetry (TSSA) of inclusive $π^0$ at center-of-mass energies ($\sqrt s$) of 200 GeV and 500 GeV in transversely polarized proton-proton collisions in the pseudo-rapidity region 2.7 to 4.0. The results at the two different energies show a continuous increase of the TSSA with Feynman-$x$, and, when compared to previous measurements, no dependence on $\sqrt s$ from 19.4 GeV to 500 GeV is found. To investigate the underlying physics leading to this large TSSA, different topologies have been studied. $π^0$ with no nearby particles tend to have a higher TSSA than inclusive $π^0$. The TSSA for inclusive electromagnetic jets, sensitive to the Sivers effect in the initial state, is substantially smaller, but shows the same behavior as the inclusive $π^0$ asymmetry as a function of Feynman-$x$. To investigate final-state effects, the Collins asymmetry of $π^0$ inside electromagnetic jets has been measured. The Collins asymmetry is analyzed for its dependence on the $π^0$ momentum transverse to the jet thrust axis and its dependence on the fraction of jet energy carried by the $π^0$. The asymmetry was found to be small in each case for both center-of-mass energies. All the measurements are compared to QCD-based theoretical calculations for transverse-momentum-dependent parton distribution functions and fragmentation functions. Some discrepancies are found, which indicates new mechanisms might be involved.
description: after replying to referee's comments. minor changes