Neutral pion cross section and spin asymmetries at intermediate pseudorapidity in polarized proton collisions at sqrt{s} = 200 GeV
Creators: name: STAR Collaboration
name: Adamczyk, L.
name: Adkins, J. K.
name: Agakishiev, G.
name: Aggarwal, M. M.
name: Ahammed, Z.
name: Alekseev, I.
name: Alford, J.
name: Anson, C. D.
name: Aparin, A.
name: Arkhipkin, D.
name: Aschenauer, E. C.
name: Averichev, G. S.
name: Balewski, J.
name: Banerjee, A.
name: Barber, B.
name: Barnovska, Z.
name: Beavis, D. R.
name: Bellwied, R.
name: Bhasin, A.
name: Bhati, A. K.
name: Bhattarai, P.
name: Bichsel, H.
name: Bielcik, J.
name: Bielcikova, J.
name: Bland, L. C.
name: Bordyuzhin, I. G.
name: Borowski, W.
name: Bouchet, J.
name: Brandin, A. V.
name: Bridgeman, A.
name: Brovko, S. G.
name: Bültmann, S.
name: Bunzarov, I.
name: Burton, T. P.
name: Butterworth, J.
name: Caines, H.
name: Sánchez, M. Calderón de la Barca
name: Cebra, D.
name: Cendejas, R.
name: Cervantes, M. C.
name: Chaloupka, P.
name: Chang, Z.
name: Chattopadhyay, S.
name: Chen, H. F.
name: Chen, J. H.
name: Chen, L.
name: Cheng, J.
name: Cherney, M.
name: Chikanian, A.
name: Christie, W.
name: Chwastowski, J.
name: Codrington, M. J. M.
name: Corliss, R.
name: Cramer, J. G.
name: Crawford, H. J.
name: Cui, X.
name: Das, S.
name: Leyva, A. Davila
name: De Silva, L. C.
name: Debbe, R. R.
name: Dedovich, T. G.
name: Deng, J.
name: Derevschikov, A. A.
name: de Souza, R. Derradi
name: Dhamija, S.
name: di Ruzza, B.
name: Didenko, L.
name: Dilks, C.
name: Ding, F.
name: Djawotho, P.
name: Dong, X.
name: Drachenberg, J. L.
name: Draper, J. E.
name: Du, C. M.
name: Dunkelberger, L. E.
name: Dunlop, J. C.
name: Efimov, L. G.
name: Engelage, J.
name: Engle, K. S.
name: Eppley, G.
name: Eun, L.
name: Evdokimov, O.
name: Fatemi, R.
name: Fazio, S.
name: Fedorisin, J.
name: Filip, P.
name: Finch, E.
name: Fisyak, Y.
name: Flores, C. E.
name: Gagliardi, C. A.
name: Gangadharan, D. R.
name: Garand, D.
name: Geurts, F.
name: Gibson, A.
name: Girard, M.
name: Gliske, S.
name: Grosnick, D.
name: Guo, Y.
name: Gupta, A.
name: Gupta, S.
name: Guryn, W.
name: Haag, B.
name: Hajkova, O.
name: Hamed, A.
name: Han, L-X.
name: Haque, R.
name: Harris, J. W.
name: Hays-Wehle, J. P.
name: He, W.
name: Heppelmann, S.
name: Hirsch, A.
name: Hoffmann, G. W.
name: Hofman, D. J.
name: Horvat, S.
name: Huang, B.
name: Huang, H. Z.
name: Huck, P.
name: Humanic, T. J.
name: Igo, G.
name: Jacobs, W. W.
name: Jang, H.
name: Judd, E. G.
name: Kabana, S.
name: Kalinkin, D.
name: Kang, K.
name: Kauder, K.
name: Ke, H. W.
name: Keane, D.
name: Kechechyan, A.
name: Kesich, A.
name: Khan, Z. H.
name: Kikola, D. P.
name: Kisel, I.
name: Kisiel, A.
name: Koetke, D. D.
name: Kollegger, T.
name: Konzer, J.
name: Koralt, I.
name: Korsch, W.
name: Kotchenda, L.
name: Kravtsov, P.
name: Krueger, K.
name: Kulakov, I.
name: Kumar, L.
name: Kycia, R. A.
name: Lamont, M. A. C.
name: Landgraf, J. M.
name: Landry, K. D.
name: Lauret, J.
name: Lebedev, A.
name: Lednicky, R.
name: Lee, J. H.
name: Leight, W.
name: LeVine, M. J.
name: Li, C.
name: Li, W.
name: Li, X.
name: Li, X.
name: Li, Y.
name: Li, Z. M.
name: Lima, L. M.
name: Lisa, M. A.
name: Liu, F.
name: Ljubicic, T.
name: Llope, W. J.
name: Longacre, R. S.
name: Luo, X.
name: Ma, G. L.
name: Ma, Y. G.
name: Don, D. M. M. D. Madagodagettige
name: Mahapatra, D. P.
name: Majka, R.
name: Manweiler, R.
name: Margetis, S.
name: Markert, C.
name: Masui, H.
name: Matis, H. S.
name: McDonald, D.
name: McShane, T. S.
name: Minaev, N. G.
name: Mioduszewski, S.
name: Mohanty, B.
name: Mondal, M. M.
name: Morozov, D. A.
name: Munhoz, M. G.
name: Mustafa, M. K.
name: Nandi, B. K.
name: Nasim, Md.
name: Nayak, T. K.
name: Nelson, J. M.
name: Nogach, L. V.
name: Noh, S. Y.
name: Nord, P. M.
name: Novak, J.
name: Nurushev, S. B.
name: Odyniec, G.
name: Ogawa, A.
name: Oh, K.
name: Ohlson, A.
name: Okorokov, V.
name: Oldag, E. W.
name: Oliveira, R. A. N.
name: Pachr, M.
name: Page, B. S.
name: Pal, S. K.
name: Pan, Y. X.
name: Pandit, Y.
name: Panebratsev, Y.
name: Pawlak, T.
name: Pawlik, B.
name: Pei, H.
name: Perkins, C.
name: Peryt, W.
name: Peterson, A.
name: Pile, P.
name: Planinic, M.
name: Pluta, J.
name: Plyku, D.
name: Pochron, W.
name: Poljak, N.
name: Porter, J.
name: Poskanzer, A. M.
name: Pruthi, N. K.
name: Przybycien, M.
name: Pujahari, P. R.
name: Qiu, H.
name: Quintero, A.
name: Ramachandran, S.
name: Raniwala, R.
name: Raniwala, S.
name: Ray, R. L.
name: Riley, C. K.
name: Ritter, H. G.
name: Roberts, J. B.
name: Rogachevskiy, O. V.
name: Romero, J. L.
name: Ross, J. F.
name: Roy, A.
name: Ruan, L.
name: Rusnak, J.
name: Sahoo, N. R.
name: Sahu, P. K.
name: Sakrejda, I.
name: Salur, S.
name: Sandacz, A.
name: Sandweiss, J.
name: Sangaline, E.
name: Sarkar, A.
name: Schambach, J.
name: Scharenberg, R. P.
name: Schaub, J.
name: Schmah, A. M.
name: Schmidke, W. B.
name: Schmitz, N.
name: Seger, J.
name: Selyuzhenkov, I.
name: Seyboth, P.
name: Shah, N.
name: Shahaliev, E.
name: Shanmuganathan, P. V.
name: Shao, M.
name: Sharma, B.
name: Shen, W. Q.
name: Shi, S. S.
name: Shou, Q. Y.
name: Sichtermann, E. P.
name: Singaraju, R. N.
name: Skoby, M. J.
name: Smirnov, D.
name: Smirnov, N.
name: Solanki, D.
name: Sorensen, P.
name: deSouza, U. G.
name: Spinka, H. M.
name: Srivastava, B.
name: Stanislaus, T. D. S.
name: Stevens, J. R.
name: Stock, R.
name: Strikhanov, M.
name: Stringfellow, B.
name: Suaide, A. A. P.
name: Sumbera, M.
name: Sun, X.
name: Sun, X. M.
name: Sun, Y.
name: Sun, Z.
name: Surrow, B.
name: Svirida, D. N.
name: Symons, T. J. M.
name: de Toledo, A. Szanto
name: Takahashi, J.
name: Tang, A. H.
name: Tang, Z.
name: Tarnowsky, T.
name: Thomas, J. H.
name: Timmins, A. R.
name: Tlusty, D.
name: Tokarev, M.
name: Trentalange, S.
name: Tribble, R. E.
name: Tribedy, P.
name: Trzeciak, B. A.
name: Tsai, O. D.
name: Turnau, J.
name: Ullrich, T.
name: Underwood, D. G.
name: Van Buren, G.
name: van Nieuwenhuizen, G.
name: Vanfossen,, J. A.
name: Varma, R.
name: Vasconcelos, G. M. S.
name: Vasiliev, A. N.
name: Vertesi, R.
name: Videbæk, F.
name: Viyogi, Y. P.
name: Vokal, S.
name: Vossen, A.
name: Wada, M.
name: Walker, M.
name: Wang, F.
name: Wang, G.
name: Wang, H.
name: Wang, J. S.
name: Wang, X. L.
name: Wang, Y.
name: Wang, Y.
name: Webb, G.
name: Webb, J. C.
name: Westfall, G. D.
name: Wieman, H.
name: Wissink, S. W.
name: Witt, R.
name: Wu, Y. F.
name: Xiao, Z.
name: Xie, W.
name: Xin, K.
name: Xu, H.
name: Xu, N.
name: Xu, Q. H.
name: Xu, Y.
name: Xu, Z.
name: Yan, W.
name: Yang, C.
name: Yang, Y.
name: Yang, Y.
name: Ye, Z.
name: Yepes, P.
name: Yi, L.
name: Yip, K.
name: Yoo, I-K.
name: Zawisza, Y.
name: Zbroszczyk, H.
name: Zha, W.
name: Zhang, J. B.
name: Zhang, S.
name: Zhang, X. P.
name: Zhang, Y.
name: Zhang, Z. P.
name: Zhao, F.
name: Zhao, J.
name: Zhong, C.
name: Zhu, X.
name: Zhu, Y. H.
name: Zoulkarneeva, Y.
name: Zyzak, M.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: The differential cross section and spin asymmetries for neutral pions produced within the intermediate pseudorapidity range 0.8 &lt; η &lt; 2.0 in polarized proton-proton collisions at sqrt{s} = 200 GeV are presented. Neutral pions were detected using the endcap electromagnetic calorimeter in the STAR detector at RHIC. The cross section was measured over a transverse momentum range of 5 &lt; p_T &lt; 16 GeV/c and is found to be within the scale uncertainty of a next-to-leading order perturbative QCD calculation. The longitudinal double-spin asymmetry, A_LL, is measured in the same pseudorapidity range. This quantity is sensitive to the gluonic contribution to the proton spin, Δg(x), at low Bjorken-x (down to x approx 0.01), where it is less constrained by measurements at central pseudorapidity. The measured A_LL is consistent with model predictions. The parity-violating asymmetry, A_L, is also measured and found to be consistent with zero. The transverse single-spin asymmetry, A_N, is measured within a previously unexplored kinematic range in Feynman-x and p_T. Such measurements may aid our understanding of the on-set and kinematic dependence of the large asymmetries observed at more forward pseudorapidity (η approx 3) and their underlying mechanisms. The A_N results presented are consistent with a twist-3 model prediction of a small asymmetry within the present kinematic range.
description: 11 pages, 9 figures, REVTeX 4.1, Submitted to Phys. Rev. D. Changes for version 2: minor textual updates, modified discussion of gluonic polarization, clarified description of Fig. 4, and corrected sign convention in Fig. 8