1. Measurement of longitudinal spin transfer to $\Lambda$ hyperons in deep inelastic lepton scattering
- Author
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Airapetian, A., Akopov, N., Amarian, M., Aschenauer, E. C., Avakian, H., Avakian, R., Avetissian, A., Bains, B., Baumgarten, C., Beckmann, M., Belostotski, S., Belz, J. E., Benisch, Th., Bernreuther, S., Bianchi, N., Blouw, J., Bottcher, H., Borissov, A., Bouwhuis, M., Brack, J., Brauksiepe, S., Braun, B., Bray, B., Brons, S., Bruckner, W., Brull, A., Bruins, E. E. W., Bulten, H. J., Capitani, G. P., Carter, P., Chumney, P., Cisbani, E., Court, G. R., Dalpiaz, P. F., De Sanctis, E., De Schepper, D., Devitsin, E., De Witt Huberts, P. K. A., Di Nezza, P., Duren, M., Dvoredsky, A., Elbakian, G., Ely, J., Fantoni, A., Fechtchenko, A., Ferstl, M., Fiedler, K., Filippone, B. W., Fischer, H., Fox, B., Franz, J., Frullani, S., Funk, M.-A., Garber, Y., Gao, H., Garibaldi, F., Gavrilov, G., Geiger, P., Gharibyan, V., Golendukhin, A., Graw, G., Grebeniouk, O., Green, P. W., Greeniaus, L. G., Grosshauser, C., Guidal, M., Gute, A., Gyurjyan, V., Haas, J. P., Haeberli, W., Hausser, O., Hansen, J.-O., Hartig, M., Hasch, D., Heinsius, F. H., Henderson, R., Henoch, M., Hertenberger, R., Holler, Y., Holt, R. J., Hoprich, W., Ihssen, H., Iodice, M., Izotov, A., Jackson, H. E., Jgoun, A., Kaiser, R., Kinney, E., Kirsch, M., Kisselev, A., Kitching, P., Kobayashi, H., Koch, N., Konigsmann, K., Kolstein, M., Kolster, H., Korotkov, V., Korsch, W., Kozlov, V., Kramer, L. H., Krivokhijine, V. G., Kurisuno, M., Kyle, G., Lachnit, W., Lenisa, P., Lorenzon, W., Makins, N. C. R., Manaenkov, S. I., Martens, F. K., Martin, J. W., Masoli, F., Mateos, A., McAndrew, M., McIlhany, K., McKeown, R. D., Meissner, F., Menden, F., Metz, A., Meyners, N., Mikloukho, O., Miller, C. A., Miller, M. A., Milner, R., Most, A., Muccifora, V., Mussa, R., Nagaitsev, A., Naryshkin, Y., Nathan, A. M., Neunreither, F., Niczyporuk, J. M., Nowak, W.-D., Nupieri, M., O'Neill, T. G., Openshaw, R., Ouyang, J., Owen, B. R., Papavassiliou, V., Pate, S. F., Pitt, M., Potashov, S., Potterveld, D. H., Rakness, G., Reali, A., Redwine, R., Reolon, A. R., Ristinen, R., Rith, K., Rossi, P., Rudnitsky, S., Ruh, M., Ryckbosch, D., Sakemi, Y., Savin, I., Scarlett, C., Schmidt, F., Schmitt, H., Schnell, G., Schuler, K. P., Schwind, A., Seibert, J., Shibata, T.-A., Shibatani, K., Shin, T., Shutov, V., Simani, C., Simon, A., Sinram, K., Slavich, P., Spengos, M., Steffens, E., Stenger, J., Stewart, J., Stosslein, U., Sutter, M., Tallini, H., Taroian, S., Terkulov, A., Thomas, E., Tipton, B., Tytgat, M., Urciuoli, G. M., Van Den Brand, J. F. J., Van Der Steenhoven, G., Van De Vyver, R., Van Hunen, J. J., Vetterli, M. C., Vikhrov, V., Vincter, M. G., Visser, J., Volk, E., Wander, W., Wendland, J., Williamson, S. E., Wise, T., Woller, K., Yoneyama, S., and Zohrabian, H.
- Subjects
positron: polarized beam ,Lambda: electroproduction ,quark model parton ,positron p: deep inelastic scattering ,up: fragmentation ,Lambda: polarization ,HERMES ,up: polarization ,+p+pi%22">Lambda --> p pi ,helicity: conservation law ,DESY HERA Stor ,27.5 GeV ,mass spectrum: (p pi-) ,angular distribution ,+Lambda%22">positron p --> Lambda ,experimental results - Abstract
Physical review / D 64(11), 112005 (2001). doi:10.1103/PhysRevD.64.112005, Spin transfer in deep-inelastic Lambda electroproduction has been studied with the HERMES detector using the 27.6 GeV polarized positron beam in the HERA storage ring. For an average fractional energy transfer = 0.45, the longitudinal spin transfer from the virtual photon to the Lambda has been extracted. The spin transfer along the Lambda momentum direction is found to be 0.11 +/- 0.17 (stat) +/- 0.03 (sys); similar values are found for other possible choices for the longitudinal spin direction of the Lambda. This result is the most precise value obtained to date from deep-inelastic scattering with charged lepton beams, and is sensitive to polarized up quark fragmentation to hyperon states. The experimental result is found to be in general agreement with various models of the Lambda spin content, and is consistent with the assumption of helicity conservation in the fragmentation process., Published by Inst., Woodbury, NY
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- 2001
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