Portal de Periódicos da CAPES

Parity-violating electroweak asymmetry in e ⃗ p scattering

2004; American Institute of Physics; Volume: 69; Issue: 6 Linguagem: Inglês

10.1103/physrevc.69.065501

1538-4497

K. Aniol, David Armstrong, T. Averett, Maud Baylac, E. Burtin, J. R. Calarco, G. D. Cates, C. Cavata, Z. Chai, C. C. Chang, J.-P. Chen, E. Chudakov, E. Cisbani, M. Coman, D. Dale, A. Deur, P. Djawotho, Michael Epstein, S. Escoffier, L. Ewell, Nicolas Falletto, J. M. Finn, K. Fissum, Andre Fleck, B. Frois, S. Frullani, J. Gao, F. Garibaldi, A. Gasparian, G. M. Gerstner, R. Gilman, A. Glamazdin, J. Gómez, V. Gorbenko, O. Hansen, F. W. Hersman, D. W. Higinbotham, R. Holmes, M. Holtrop, T. B. Humensky, S. Incerti, M. Iodice, C. W. de Jager, J. Jardillier, X. Jiang, M. Jones, Jean-Paul Jorda, C. Jutier, W. Kahl, James J. Kelly, D. H. Kim, M.-J. Kim, M. S. Kim, I. K. Kominis, Edgar E. Kooijman, K. Kramer, K.S. Kumar, C. C. Kuo, J. J. LeRose, R. De Leo, M. Leuschner, D. Lhuillier, M. Liang, N. Liyanage, R. Lourie, R. Madey, S. Malov, D. J. Margaziotis, F. Marie, P. Markowitz, J. Martino, P. Mastromarino, K. McCormick, Justin I. McIntyre, Z.-E. Meziani, R. Michaels, B. D. Milbrath, G. W. Miller, Jason W. Mitchell, L. Morand, D. Neyret, C. Pedrisat, G. G. Petratos, R. Pomatsalyuk, Jack Price, D. L. Prout, V. Punjabi, T. Pussieux, G. Qúeḿener, R. D. Ransome, D. Relyea, Y. Roblin, J. Roche, G. A. Rutledge, P. M. Rutt, M. Rvachev, F. Sabatié, A. Saha, P. A. Souder, Marcus Spradlin, S. Strauch, R. Suleiman, J. A. Templon, T. Teresawa, J. Thompson, R. Tieulent, L. Todor, Baris T. Tonguc, P. E. Ulmer, G. M. Urciuoli, Branislav Vlahović, K. Wijesooriya, R. J. Wilson, B. Wojtsekhowski, R. J. Woo, W. Xu, Z. You, C. Zhang,

Dark Matter and Cosmic Phenomena

We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from protons. Significant contributions to this asymmetry could arise from the contributions of strange form factors in the nucleon. The measured asymmetry is $A=\ensuremath{-}15.05\ifmmode\pm\else\textpm\fi{}0.98(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.56(\mathrm{syst})\phantom{\rule{0.3em}{0ex}}\mathrm{ppm}$ at the kinematic point $⟨{\ensuremath{\theta}}_{\mathrm{lab}}⟩=12.3\ifmmode^\circ\else\textdegree\fi{}$ and $⟨{Q}^{2}⟩=0.477\phantom{\rule{0.3em}{0ex}}{(\mathrm{GeV}∕c)}^{2}$. Based on these data as well as data on electromagnetic form factors, we extract the linear combination of strange form factors ${G}_{E}^{s}+0.392{G}_{M}^{s}=0.014\ifmmode\pm\else\textpm\fi{}0.020\ifmmode\pm\else\textpm\fi{}0.010$, where the first error arises from this experiment and the second arises from the electromagnetic form factor data. This paper provides a full description of the special experimental techniques employed for precisely measuring the small asymmetry, including the first use of a strained GaAs crystal and a laser-Compton polarimeter in a fixed target parity-violation experiment.