Polarised quark distributions in the nucleon from semi-inclusive spin asymmetries

Adeva, B; Akdogan, T; Arik, E; Arvidson, A; Badelek, B; Bardin, G; Baum, G; Berglund, P; Betev, L; Birsa, R; de Botton, N; Bradamante, F; Bravar, A; Bressan, A; Bultmann, S; Burtin, E; Crabb, D; Cranshaw, J; Cuhadar, T; Dalla Torre, S; van Dantzig, R; Derro, B; Deshpande, A; Dhawan, S; Dulya, C; Eichblatt, S; Fasching, D; Feinstein, F; Fernandez, C; Forthmann, S; Frois, B; Gallas, A; Garzon, JA; Gilly, H; Giorgi, M; von Goeler, E; Goertz, S; Gracia, G; de Groot, N; Grosse Perdekamp, M; Haft, K; von Harrach, D; Hasegawa, T; Hautle, P; Hayashi, N; Heusch, CA; Horikawa, N; Hughes, VW; Igo, G; Ishimoto, S; Iwata, T; Kabuss, EM; Kageya, T; Karev, A; Kessler, HJ; Ketel, TJ; Kiryluk, J; Kisselev, Y; Kramer, D; Krivokhijine, V; Kroger, W; Kukhtin, V; Kurek, K; Kyynarainen, J; Lamanna, M; Landgraf, U; Le Goff, JM; Lehar, F; de Lesquen, A; Lichtenstadt, J; Litmaath, M; Magnon, A; Mallot, GK; Marie, F; Martin, A; Martino, J; Matsuda, T; Mayes, B; McCarthy, JS; Medved, K; Meyer, W; van Middelkoop, G; Miller, D; Miyachi, Y; Mori, K; Moromisato, J; Nassalski, J; Naumann, L; Niinikoski, TO; Oberski, JEJ; Ogawa, A; Özben, Cenap; Pereira, H; Perrot-Kunne, F; Peshekhonov, D; Pinsky, L; Platchkov, S; Plo, M; Pose, D; Postma, H; Pretz, J; Puntaferro, R; Radel, G; Rijllart, A; Reicherz, G; Roberts, J; Rodriguez, M; Rondio, E; Roscherr, B; Sabo, I; Saborido, J; Sandacz, A; Savin, I; Schiavon, P; Schiller, A; Sichtermann, EP; Simeoni, F; Smirnov, GI; Staude, A; Steinmetz, A; Stiegler, U; Stuhrmann, H; Szleper, M; Tessarotto, F; Thers, D; Tlaczala, W; Tripet, A; Unel, G; Velasco, M; Vogt, J; Voss, R; Whitten, C; Windmolders, R; Willumeit, R; Wislicki, W; Witzmann, A; Ylostalo, J; Zanetti, AM; Zaremba, K; Zhao, J

doi:10.1016/s0370-2693(97)01546-3

Polarised quark distributions in the nucleon from semi-inclusive spin asymmetries

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Adeva B., Akdogan T., Arik E., Arvidson A., Badelek B., Bardin G., ...More

PHYSICS LETTERS B, vol.420, pp.180-190, 1998 (SCI-Expanded)

Publication Type: Article / Article
Volume: 420
Publication Date: 1998
Doi Number: 10.1016/s0370-2693(97)01546-3
Journal Name: PHYSICS LETTERS B
Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
Page Numbers: pp.180-190
Istanbul Technical University Affiliated: No

Abstract

We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 0.003 < x < 0.7 and Q(2) > 1 GeV2. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at Q(2) = 10 GeV2. The polarised u valence quark distribution, Delta u(v)(x), is positive and the polarisation increases with x. The polarised d valence quark distribution, Delta d(v)(x), is negative and the non-strange sea distribution, Delta (q) over bar(x), is consistent with zero over the measured range of x. We find for the first moments integral(0)(1) Delta u(v)(x)d x = 0.77 +/- 0.10 +/- 0.08, integral(0)(1) Delta d(v)(x)d x = -0.52 +/- 0.14 +/- 0.09 and integral(0)(1) Delta (q) over bar(x)d x = 0.01 +/- 0.04 +/- 0.03, where we assumed Delta (u) over bar(x) = Delta (d) over bar(x). We also determine for the first time the second moments of the valence distributions integral(0)(1)x Delta q(v)(x)d x. (C) 1998 Published by Elsevier Science B.V.