Double helicity asymmetry in inclusive midrapidity pi0 production for polarized p+p collisions at square root s = 200 GeV

S S Adler; S Afanasiev; C Aidala; N N Ajitanand; Y Akiba; A Al-Jamel; J Alexander; K Aoki; L Aphecetche; R Armendariz; S H Aronson; R Averbeck; T C Awes; V Babintsev; A Baldisseri; K N Barish; P D Barnes; B Bassalleck; S Bathe; S Batsouli; V Baublis; F Bauer; A Bazilevsky; S Belikov; M T Bjorndal; J G Boissevain; H Borel; M L Brooks; D S Brown; N Bruner; D Bucher; H Buesching; V Bumazhnov; G Bunce; J M Burward-Hoy; S Butsyk; X Camard; P Chand; W C Chang; S Chernichenko; C Y Chi; J Chiba; M Chiu; I J Choi; R K Choudhury; T Chujo; V Cianciolo; Y Cobigo; B A Cole; M P Comets; P Constantin; M Csanád; T Csörgo; J P Cussonneau; D d'Enterria; K Das; G David; F Deák; H Delagrange; A Denisov; A Deshpande; E J Desmond; A Devismes; O Dietzsch; J L Drachenberg; O Drapier; A Drees; A Durum; D Dutta; V Dzhordzhadze; Y V Efremenko; H En'yo; B Espagnon; S Esumi; D E Fields; C Finck; F Fleuret; S L Fokin; B D Fox; Z Fraenkel; J E Frantz; A Franz; A D Frawley; Y Fukao; S-Y Fung; S Gadrat; M Germain; A Glenn; M Gonin; J Gosset; Y Goto; R Granier de Cassagnac; N Grau; S V Greene; M Grosse Perdekamp; H-A Gustafsson; T Hachiya; J S Haggerty; H Hamagaki; A G Hansen; E P Hartouni; M Harvey; K Hasuko; R Hayano; X He; M Heffner; T K Hemmick; J M Heuser; P Hidas; H Hiejima; J C Hill; R Hobbs; W Holzmann; K Homma; B Hong; A Hoover; T Horaguchi; T Ichihara; V V Ikonnikov; K Imai; M Inaba; M Inuzuka; D Isenhower; L Isenhower; M Ishihara; M Issah; A Isupov; B V Jacak; J Jia; O Jinnouchi; B M Johnson; S C Johnson; K S Joo; D Jouan; F Kajihara; S Kametani; N Kamihara; M Kaneta; J H Kang; K Katou; T Kawabata; A Kazantsev; S Kelly; B Khachaturov; A Khanzadeev; J Kikuchi; D J Kim; E Kim; G-B Kim; H J Kim; E Kinney; A Kiss; E Kistenev; A Kiyomichi; C Klein-Boesing; H Kobayashi; V Kochetkov; R Kohara; B Komkov; M Konno; D Kotchetkov; A Kozlov; P J Kroon; C H Kuberg; G J Kunde; K Kurita; M J Kweon; Y Kwon; G S Kyle; R Lacey; J G Lajoie; Y Le Bornec; A Lebedev; S Leckey; D M Lee; M J Leitch; M A L Leite; X Li; X H Li; H Lim; A Litvinenko; M X Liu; C F Maguire; Y I Makdisi; A Malakhov; V I Manko; Y Mao; G Martinez; H Masui; F Matathias; T Matsumoto; M C McCain; P L McGaughey; Y Miake; T E Miller; A Milov; S Mioduszewski; G C Mishra; J T Mitchell; A K Mohanty; D P Morrison; J M Moss; D Mukhopadhyay; M Muniruzzaman; S Nagamiya; J L Nagle; T Nakamura; J Newby; A S Nyanin; J Nystrand; E O'brien; C A Ogilvie; H Ohnishi; I D Ojha; H Okada; K Okada; A Oskarsson; I Otterlund; K Oyama; K Ozawa; D Pal; A P T Palounek; V Pantuev; V Papavassiliou; J Park; W J Park; S F Pate; H Pei; V Penev; J-C Peng; H Pereira; V Peresedov; A Pierson; C Pinkenburg; R P Pisani; M L Purschke; A K Purwar; J Qualls; J Rak; I Ravinovich; K F Read; M Reuter; K Reygers; V Riabov; Y Riabov; G Roche; A Romana; M Rosati; S Rosendahl; P Rosnet; V L Rykov; S S Ryu; N Saito; T Sakaguchi; S Sakai; V Samsonov; L Sanfratello; R Santo; H D Sato; S Sato; S Sawada; Y Schutz; V Semenov; R Seto; T K Shea; I Shein; T-A Shibata; K Shigaki; M Shimomura; A Sickles; C L Silva; D Silvermyr; K S Sim; A Soldatov; R A Soltz; W E Sondheim; S Sorensen; I V Sourikova; F Staley; P W Stankus; E Stenlund; M Stepanov; A Ster; S P Stoll; T Sugitate; J P Sullivan; S Takagi; E M Takagui; A Taketani; K H Tanaka; Y Tanaka; K Tanida; M J Tannenbaum; A Taranenko; P Tarján; T L Thomas; M Togawa; J Tojo; H Torii; R S Towell; V-N Tram; I Tserruya; Y Tsuchimoto; H Tydesjö; N Tyurin; T J Uam; H W van Hecke; J Velkovska; M Velkovsky; V Veszprémi; A A Vinogradov; M A Volkov; E Vznuzdaev; X R Wang; Y Watanabe; S N White; N Willis; F K Wohn; C L Woody; W Xie; A Yanovich; S Yokkaichi; G R Young; I E Yushmanov; W A Zajc; O Zaudtke; C Zhang; S Zhou; J Zimányi; L Zolin; X Zong; PHENIX Collaboration

doi:10.1103/PhysRevLett.93.202002

Double helicity asymmetry in inclusive midrapidity pi0 production for polarized p+p collisions at square root s = 200 GeV

Phys Rev Lett. 2004 Nov 12;93(20):202002. doi: 10.1103/PhysRevLett.93.202002. Epub 2004 Nov 11.

Authors

S S Adler¹, S Afanasiev, C Aidala, N N Ajitanand, Y Akiba, A Al-Jamel, J Alexander, K Aoki, L Aphecetche, R Armendariz, S H Aronson, R Averbeck, T C Awes, V Babintsev, A Baldisseri, K N Barish, P D Barnes, B Bassalleck, S Bathe, S Batsouli, V Baublis, F Bauer, A Bazilevsky, S Belikov, M T Bjorndal, J G Boissevain, H Borel, M L Brooks, D S Brown, N Bruner, D Bucher, H Buesching, V Bumazhnov, G Bunce, J M Burward-Hoy, S Butsyk, X Camard, P Chand, W C Chang, S Chernichenko, C Y Chi, J Chiba, M Chiu, I J Choi, R K Choudhury, T Chujo, V Cianciolo, Y Cobigo, B A Cole, M P Comets, P Constantin, M Csanád, T Csörgo, J P Cussonneau, D d'Enterria, K Das, G David, F Deák, H Delagrange, A Denisov, A Deshpande, E J Desmond, A Devismes, O Dietzsch, J L Drachenberg, O Drapier, A Drees, A Durum, D Dutta, V Dzhordzhadze, Y V Efremenko, H En'yo, B Espagnon, S Esumi, D E Fields, C Finck, F Fleuret, S L Fokin, B D Fox, Z Fraenkel, J E Frantz, A Franz, A D Frawley, Y Fukao, S-Y Fung, S Gadrat, M Germain, A Glenn, M Gonin, J Gosset, Y Goto, R Granier de Cassagnac, N Grau, S V Greene, M Grosse Perdekamp, H-A Gustafsson, T Hachiya, J S Haggerty, H Hamagaki, A G Hansen, E P Hartouni, M Harvey, K Hasuko, R Hayano, X He, M Heffner, T K Hemmick, J M Heuser, P Hidas, H Hiejima, J C Hill, R Hobbs, W Holzmann, K Homma, B Hong, A Hoover, T Horaguchi, T Ichihara, V V Ikonnikov, K Imai, M Inaba, M Inuzuka, D Isenhower, L Isenhower, M Ishihara, M Issah, A Isupov, B V Jacak, J Jia, O Jinnouchi, B M Johnson, S C Johnson, K S Joo, D Jouan, F Kajihara, S Kametani, N Kamihara, M Kaneta, J H Kang, K Katou, T Kawabata, A Kazantsev, S Kelly, B Khachaturov, A Khanzadeev, J Kikuchi, D J Kim, E Kim, G-B Kim, H J Kim, E Kinney, A Kiss, E Kistenev, A Kiyomichi, C Klein-Boesing, H Kobayashi, V Kochetkov, R Kohara, B Komkov, M Konno, D Kotchetkov, A Kozlov, P J Kroon, C H Kuberg, G J Kunde, K Kurita, M J Kweon, Y Kwon, G S Kyle, R Lacey, J G Lajoie, Y Le Bornec, A Lebedev, S Leckey, D M Lee, M J Leitch, M A L Leite, X Li, X H Li, H Lim, A Litvinenko, M X Liu, C F Maguire, Y I Makdisi, A Malakhov, V I Manko, Y Mao, G Martinez, H Masui, F Matathias, T Matsumoto, M C McCain, P L McGaughey, Y Miake, T E Miller, A Milov, S Mioduszewski, G C Mishra, J T Mitchell, A K Mohanty, D P Morrison, J M Moss, D Mukhopadhyay, M Muniruzzaman, S Nagamiya, J L Nagle, T Nakamura, J Newby, A S Nyanin, J Nystrand, E O'brien, C A Ogilvie, H Ohnishi, I D Ojha, H Okada, K Okada, A Oskarsson, I Otterlund, K Oyama, K Ozawa, D Pal, A P T Palounek, V Pantuev, V Papavassiliou, J Park, W J Park, S F Pate, H Pei, V Penev, J-C Peng, H Pereira, V Peresedov, A Pierson, C Pinkenburg, R P Pisani, M L Purschke, A K Purwar, J Qualls, J Rak, I Ravinovich, K F Read, M Reuter, K Reygers, V Riabov, Y Riabov, G Roche, A Romana, M Rosati, S Rosendahl, P Rosnet, V L Rykov, S S Ryu, N Saito, T Sakaguchi, S Sakai, V Samsonov, L Sanfratello, R Santo, H D Sato, S Sato, S Sawada, Y Schutz, V Semenov, R Seto, T K Shea, I Shein, T-A Shibata, K Shigaki, M Shimomura, A Sickles, C L Silva, D Silvermyr, K S Sim, A Soldatov, R A Soltz, W E Sondheim, S Sorensen, I V Sourikova, F Staley, P W Stankus, E Stenlund, M Stepanov, A Ster, S P Stoll, T Sugitate, J P Sullivan, S Takagi, E M Takagui, A Taketani, K H Tanaka, Y Tanaka, K Tanida, M J Tannenbaum, A Taranenko, P Tarján, T L Thomas, M Togawa, J Tojo, H Torii, R S Towell, V-N Tram, I Tserruya, Y Tsuchimoto, H Tydesjö, N Tyurin, T J Uam, H W van Hecke, J Velkovska, M Velkovsky, V Veszprémi, A A Vinogradov, M A Volkov, E Vznuzdaev, X R Wang, Y Watanabe, S N White, N Willis, F K Wohn, C L Woody, W Xie, A Yanovich, S Yokkaichi, G R Young, I E Yushmanov, W A Zajc, O Zaudtke, C Zhang, S Zhou, J Zimányi, L Zolin, X Zong; PHENIX Collaboration

Affiliation

¹ Brookhaven National Laboratory, Upton, New York 11973-5000, USA.

PMID: 15600917
DOI: 10.1103/PhysRevLett.93.202002

Abstract

We present a measurement of the double longitudinal spin asymmetry in inclusive pi(0) production in polarized proton-proton collisions at sqrt[s]=200 GeV. The data were taken at the Relativistic Heavy Ion Collider with average beam polarizations of 0.27. The measurements are the first in a program to study the longitudinal spin structure of the proton, using strongly interacting probes, at collider energies. The asymmetry is presented for transverse momenta 1-5 GeV/c at midrapidity, where next-to-leading-order perturbative quantum chromodynamic (NLO pQCD) calculations well describe the unpolarized cross section. The observed asymmetry is small and is compared to a NLO pQCD calculation with a range of polarized gluon distributions.