Measurement of the Λ polarization in νμ charged current interactions in the NOMAD experiment

P. Astier, D. Autiero, A. Baldisseri, M. Baldo-Ceolin, M. Banner, G. Bassompierre, K. Benslama, N. Besson, I. Bird, B. Blumenfeld, F. Bobisut, J. Bouchez, S. Boyd, A. Bueno, S. Bunyatov, L. Camilleri, A. Cardini, P. W. Cattaneo, V. Cavasinni, A. Cervera-VillanuevaA. Chukanov, G. Collazuol, G. Conforto, C. Conta, M. Contalbrigo, R. Cousins, D. Daniels, H. Degaudenzi, T. del Prete, A. de Santo, T. Dignan, L. di Lella, E. do Couto e Silva, J. Dumarchez, M. Ellis, T. Fazio, G. J. Feldman, R. Ferrari, D. Ferrère, V. Flaminio, M. Fraternali, J. M. Gaillard, E. Gangler, A. Geiser, D. Geppert, D. Gibin, S. Gninenko, A. Godley, J. J. Gomez-Cadenas, J. Gosset, C. Gößling, M. Gouanère, A. Grant, G. Graziani, A. Guglielmi, C. Hagner, J. Hernando, D. Hubbard, P. Hurst, N. Hyett, E. Iacopini, C. Joseph, F. Juget, M. Kirsanov, O. Klimov, J. Kokkonen, A. Kovzelev, A. Krasnoperov, D. Kustov, V. Kuznetsov, S. Lacaprara, C. Lachaud, B. Lakić, A. Lanza, L. la Rotonda, M. Laveder, A. Letessier-Selvon, J. M. Levy, L. Linssen, A. Ljubičić, J. Long, A. Lupi, A. Marchionni, F. Martelli, X. Méchain, J. P. Mendiburu, J. P. Meyer, M. Mezzetto, S. R. Mishra, G. F. Moorhead, D. Naumov, P. Nédélec, Yu Nefedov, C. Nguyen-Mau, D. Orestano, F. Pastore, L. S. Peak, E. Pennacchio, H. Pessard, R. Petti, A. Placci, G. Polesello, D. Pollmann, A. Polyarush, B. Popov, C. Poulsen, P. Rathouit, J. Rico, P. Riemann, C. Roda, A. Rubbia, F. Salvatore, K. Schahmaneche, B. Schmidt, T. Schmidt, M. Sevior, D. Sillou, F. J.P. Soler, G. Sozzi, D. Steele, U. Stiegler, M. Stipčević, Th Stolarczyk, M. Tareb-Reyes, G. N. Taylor, V. Tereshchenko, A. Toropin, A. M. Touchard, S. N. Tovey, M. T. Tran, E. Tsesmelis, J. Ulrichs, L. Vacavant, M. Valdata-Nappi, V. Valuev, F. Vannucci, K. E. Varvell, M. Veltri, V. Vercesi, J. M. Vieira, T. Vinogradova, F. V. Weber, T. Weisse, F. F. Wilson, L. J. Winton, B. D. Yabsley, H. Zaccone, K. Zuber, P. Zuccon

Research output: Contribution to journalArticle

83 Scopus citations

Abstract

The Λ polarization in νμ charged current interactions has been measured in the NOMAD experiment. The event sample (8087 reconstructed Λ 's) is more than an order of magnitude larger than that of previous bubble chamber experiments, while the quality of event reconstruction is comparable. We observe negative polarization along the W -boson direction which is enhanced in the target fragmentation region: Px(xF<0)=-0.21±0.04(stat)±0.02(sys) . In the current fragmentation region we find Px(xF>0)=-0.09±0.06(stat)±0.03(sys) . These results provide a test of different models describing the nucleon spin composition and the spin transfer mechanisms. A significant transverse polarization (in the direction orthogonal to the Λ production plane) has been observed for the first time in a neutrino experiment: Py=-0.22±0.03(stat)±0.01(sys) . The dependence of the absolute value of Py on the Λ transverse momentum with respect to the hadronic jet direction is in qualitative agreement with the results from unpolarized hadron-hadron experiments.

Original languageEnglish (US)
Pages (from-to)3-36
Number of pages34
JournalNuclear Physics B
Volume588
Issue number1-2
DOIs
StatePublished - Nov 6 2000

Keywords

  • Lambda polarization
  • Neutrino interactions
  • Nucleon spin
  • Spin transfer

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

Fingerprint Dive into the research topics of 'Measurement of the Λ polarization in ν<sub>μ</sub> charged current interactions in the NOMAD experiment'. Together they form a unique fingerprint.

  • Cite this

    Astier, P., Autiero, D., Baldisseri, A., Baldo-Ceolin, M., Banner, M., Bassompierre, G., Benslama, K., Besson, N., Bird, I., Blumenfeld, B., Bobisut, F., Bouchez, J., Boyd, S., Bueno, A., Bunyatov, S., Camilleri, L., Cardini, A., Cattaneo, P. W., Cavasinni, V., ... Zuccon, P. (2000). Measurement of the Λ polarization in νμ charged current interactions in the NOMAD experiment. Nuclear Physics B, 588(1-2), 3-36. https://doi.org/10.1016/S0550-3213(00)00503-4