Measurement of transverse single-spin asymmetries for midrapidity production of neutral pions and charged hadrons in polarized p + p collisions at square root(s) = 200 GeV

• Published in: Physical review letters 2005-11, Vol.95 (20), p.202001-202001
• Main Authors: Adler, S S, Afanasiev, S, Aidala, C, Ajitanand, N N, Akiba, Y, Alexander, J, Amirikas, R, Aphecetche, L, Aronson, S H, Averbeck, R, Awes, T C, Azmoun, R, Babintsev, V, Baldisseri, A, Barish, K N, Barnes, P D, Bassalleck, B, Bathe, S, Batsouli, S, Baublis, V, Bauer, F, Bazilevsky, A, Belikov, S, Berdnikov, Y, Bhagavatula, S, Boissevain, J G, Borel, H, Borenstein, S, Brooks, M L, Brown, D S, Bruner, N, Bucher, D, Buesching, H, Bumazhnov, V, Bunce, G, Burward-Hoy, J M, Butsyk, S, Camard, X, Chai, J-S, Chand, P, Chang, W C, Chernichenko, S, Chi, C Y, Chiba, J, Chiu, M, Choi, I J, Choi, J, Choudhury, R K, Chujo, T, Cianciolo, V, Cobigo, Y, Cole, B A, Constantin, P, d'Enterria, D, David, G, Delagrange, H, Denisov, A, Deshpande, A, Desmond, E J, Devismes, A, Dietzsch, O, Drapier, O, Drees, A, Drees, K A, du Rietz, R, Durum, A, Dutta, D, Efremenko, Y V, El Chenawi, K, Enokizono, A, En'yo, H, Esumi, S, Ewell, L, Fields, D E, Fleuret, F, Fokin, S L, Fox, B D, Fraenkel, Z, Frantz, J E, Franz, A, Frawley, A D, Fung, S-Y, Garpman, S, Ghosh, T K, Glenn, A, Gogiberidze, G, Gonin, M, Gosset, J, Goto, Y, Granier de Cassagnac, R, Grau, N, Greene, S V, Grosse Perdekamp, M, Guryn, W, Gustafsson, H-A, Hachiya, T, Haggerty, J S, Hamagaki, H, Hansen, A G, Hartouni, E P
• Format: Article
• Language: English
• ISSN: 0031-9007

Transverse single-spin asymmetries to probe the transverse-spin structure of the proton have been measured for neutral pions and nonidentified charged hadrons from polarized proton-proton collisions at midrapidity and square root(s) = 200 GeV. The data cover a transverse momentum (pT) range 1.0-5.0 GeV/c for neutral pions and 0.5-5.0 GeV/c for charged hadrons, at a Feynman-x value of approximately zero. The asymmetries seen in this previously unexplored kinematic region are consistent with zero within errors of a few percent. In addition, the inclusive charged hadron cross section at midrapidity from 0.5 < pT < 7.0 GeV/c is presented and compared to next-to-leading order perturbative QCD (pQCD) calculations. Successful description of the unpolarized cross section above approximately 2 GeV/c suggests that pQCD is applicable in the interpretation of the asymmetry results in the relevant kinematic range.