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

B. Adeva, T. Akdogan, E. Arik, A. Arvidson, B. Badelek, G. Bardin, G. Baum, P. Berglund, L. Betev, R. Birsa, N. de Botton, F. Bradamante, A. Bravar, A. Bressan, S. Bültmann, E. Burtin, D. Crabb, J. Cranshaw, T. Çuhadar, S. Dalla TorreR. van Dantzig, B. Derro, A. Deshpande, S. Dhawan, C. Dulya, S. Eichblatt, D. Fasching, F. Feinstein, C. Fernandez, S. Forthmann, B. Frois, A. Gallas, J. A. Garzon, H. Gilly, M. Giorgi, E. von Goeler, S. Goertz, G. Gracia, N. de Groot, M. Grosse Perdekamp, K. Haft, D. von Harrach, T. Hasegawa, P. Hautle, N. Hayashi, C. A. Heusch, N. Horikawa, V. W. Hughes, G. Igo, S. Ishimoto, T. Iwata, E. M. Kabuß, T. Kageya, A. Karev, H. J. Kessler, T. J. Ketel, J. Kiryluk, Y. Kisselev, D. Krämer, V. Krivokhijine, W. Kröger, V. Kukhtin, K. Kurek, J. Kyynäräinen, M. Lamanna, U. Landgraf, J. M. Le Goff, F. Lehar, A. de Lesquen, J. Lichtenstadt, M. Litmaath, A. Magnon, G. K. Mallot, F. Marie, A. Martin, J. Martino, T. Matsuda, B. Mayes, J. S. McCarthy, K. Medved, W. Meyer, G. van Middelkoop, D. Miller, Y. Miyachi, K. Mori, J. Moromisato, J. Nassalski, L. Naumann, T. O. Niinikoski, J. E.J. Oberski, A. Ogawa, C. Ozben, H. Pereira, F. Perrot-Kunne, D. Peshekhonov, L. Pinsky, S. Platchkov, M. Plo, D. Pose, H. Postma

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197 Citations (Scopus)


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 Q2 > 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 Q2 = 10 GeV2. The polarised u valence quark distribution, Δuυ(×), is positive and the polarisation increases with x. The polarised d valence quark distribution, Δdυ(x), is negative and the non-strange sea distribution, Δq-(x), is consistent with zero over the measured range of x. We find for the first moments (latin small letter esh)10Δuυ(x)d x = 0.77 ± 0.10 ± 0.08, (latin small letter esh)10Δdυ(x)d x = -0.52 ± 0.14 ± 0.09 and (latin small letter esh)10Δq-(x)d x = 0.01 ± 0.04 ± 0.03, where we assumed Δu-(x) = Δd-(x). We also determine for the first time the second moments of the valence distributions (latin small letter esh)10xΔqυ(x)d x. © 1998 Published by Elsevier Science B.V.
Original languageEnglish
Pages (from-to)180-190
Number of pages11
JournalPhysics Letters Section B: Nuclear, Elementary Particle and High-Energy Physics
Issue number1-2
Publication statusPublished - 19 Feb 1998
MoE publication typeA1 Journal article-refereed


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