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Precision Determination of the Neutron Spin Structure Function g 1 n

1997; American Physical Society; Volume: 79; Issue: 1 Linguagem: Inglês

10.1103/physrevlett.79.26

1092-0145

K. Abe, T. Akagi, B. D. Anderson, P.L. Anthony, R. G. Arnold, T. Averett, H. R. Band, C.M. Berisso, P. Bogorad, H. Borel, P. Bosted, Vincent Breton, M. Buénerd, G. D. Cates, T. E. Chupp, S. Churchwell, K. P. Coulter, M. Daoudi, P. Decowski, R. Erickson, J. Fellbaum, H. Fonvieille, R. Gearhart, V. Ghazikhanian, K. A. Griffioen, R. S. Hicks, R. Holmes, E. W. Hughes, G. Igo, S. Incerti, J. R. Johnson, W. Kahl, M. Khayat, Yu. G. Kolomensky, S. E. Kuhn, K.S. Kumar, M. Kuriki, R. M. Lombard-Nelsen, D. M. Manley, J. Marroncle, T. Maruyama, T. Marvin, W. Meyer, Z.-E. Meziani, D. H. Miller, Gregory S. Mitchell, M. Olson, G. A. Peterson, G. G. Petratos, R. Pitthan, R. Prepost, P. Raines, B. A. Raue, D. Reyna, L.S. Rochester, S. E. Rock, Michael Romalis, F. Sabatié, G. Shapiro, J. Shaw, T Smith, L. Sorrell, P. A. Souder, F. Staley, S. St. Lorant, L. M. Stuart, F. Suekane, Z. M. Szalata, Y. Terrien, A. K. Thompson, T. Toole, X. Wang, J. W. Watson, Robert C. Welsh, F. R. Wesselmann, T. Wright, C. C. Young, B. Youngman, H. Yuta, Wei-Min Zhang, P. Żyła,

Atomic and Subatomic Physics Research

We report on a precision measurement of the neutron spin structure function ${g}_{1}^{n}$ using deep inelastic scattering of polarized electrons by polarized ${}^{3}\mathrm{He}$. For the kinematic range $0.014<x<0.7$ and $1<{Q}^{2}<17(\mathrm{GeV}/c{)}^{2}$, we obtain $\ensuremath{\int}{0.014}^{0.7}{g}_{1}^{n}(x)dx\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\ensuremath{-}0.036\ifmmode\pm\else\textpm\fi{}0.004(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.005(\mathrm{syst})$ at an average ${Q}^{2}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}5(\mathrm{GeV}/c{)}^{2}$. We find relatively large negative values for ${g}_{1}^{n}$ at low $x$. The results call into question the usual Regge theory method for extrapolating to $x\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0$ to find the full neutron integral $\ensuremath{\int}{1}^{}{g}_{1}^{n}(x)\mathrm{dx}$, needed for testing the quark-parton model and QCD sum rules.