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 language | English |
---|---|
Pages (from-to) | 3-36 |
Number of pages | 34 |
Journal | Nuclear Physics B |
Volume | 588 |
Issue number | 1-2 |
DOIs | |
Publication status | Published - 6 Nov 2000 |
Externally published | Yes |
Keywords
- Lambda polarization
- Neutrino interactions
- Nucleon spin
- Spin transfer
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Measurement of the Λ polarization in νμ charged current interactions in the NOMAD experiment. / Astier, P.; Autiero, D.; Baldisseri, A. et al.
In: Nuclear Physics B, Vol. 588, No. 1-2, 06.11.2000, p. 3-36.Research output: Contribution to journal › Article › Research › peer-review
TY - JOUR
T1 - Measurement of the Λ polarization in νμ charged current interactions in the NOMAD experiment
AU - Astier, P.
AU - Autiero, D.
AU - Baldisseri, A.
AU - Baldo-Ceolin, M.
AU - Banner, M.
AU - Bassompierre, G.
AU - Benslama, K.
AU - Besson, N.
AU - Bird, I.
AU - Blumenfeld, B.
AU - Bobisut, F.
AU - Bouchez, J.
AU - Boyd, S.
AU - Bueno, A.
AU - Bunyatov, S.
AU - Camilleri, L.
AU - Cardini, A.
AU - Cattaneo, P. W.
AU - Cavasinni, V.
AU - Cervera-Villanueva, A.
AU - Chukanov, A.
AU - Collazuol, G.
AU - Conforto, G.
AU - Conta, C.
AU - Contalbrigo, M.
AU - Cousins, R.
AU - Daniels, D.
AU - Degaudenzi, H.
AU - del Prete, T.
AU - de Santo, A.
AU - Dignan, T.
AU - di Lella, L.
AU - do Couto e Silva, E.
AU - Dumarchez, J.
AU - Ellis, M.
AU - Fazio, T.
AU - Feldman, G. J.
AU - Ferrari, R.
AU - Ferrère, D.
AU - Flaminio, V.
AU - Fraternali, M.
AU - Gaillard, J. M.
AU - Gangler, E.
AU - Geiser, A.
AU - Geppert, D.
AU - Gibin, D.
AU - Gninenko, S.
AU - Godley, A.
AU - Gomez-Cadenas, J. J.
AU - Gosset, J.
AU - Gößling, C.
AU - Gouanère, M.
AU - Grant, A.
AU - Graziani, G.
AU - Guglielmi, A.
AU - Hagner, C.
AU - Hernando, J.
AU - Hubbard, D.
AU - Hurst, P.
AU - Hyett, N.
AU - Iacopini, E.
AU - Joseph, C.
AU - Juget, F.
AU - Kirsanov, M.
AU - Klimov, O.
AU - Kokkonen, J.
AU - Kovzelev, A.
AU - Krasnoperov, A.
AU - Kustov, D.
AU - Kuznetsov, V.
AU - Lacaprara, S.
AU - Lachaud, C.
AU - Lakić, B.
AU - Lanza, A.
AU - la Rotonda, L.
AU - Laveder, M.
AU - Letessier-Selvon, A.
AU - Levy, J. M.
AU - Linssen, L.
AU - Ljubičić, A.
AU - Long, J.
AU - Lupi, A.
AU - Marchionni, A.
AU - Martelli, F.
AU - Méchain, X.
AU - Mendiburu, J. P.
AU - Meyer, J. P.
AU - Mezzetto, M.
AU - Mishra, S. R.
AU - Moorhead, G. F.
AU - Naumov, D.
AU - Nédélec, P.
AU - Nefedov, Yu
AU - Nguyen-Mau, C.
AU - Orestano, D.
AU - Pastore, F.
AU - Peak, L. S.
AU - Pennacchio, E.
AU - Pessard, H.
AU - Petti, R.
AU - Placci, A.
AU - Polesello, G.
AU - Pollmann, D.
AU - Polyarush, A.
AU - Popov, B.
AU - Poulsen, C.
AU - Rathouit, P.
AU - Rico, J.
AU - Riemann, P.
AU - Roda, C.
AU - Rubbia, A.
AU - Salvatore, F.
AU - Schahmaneche, K.
AU - Schmidt, B.
AU - Schmidt, T.
AU - Sevior, M.
AU - Sillou, D.
AU - Soler, F. J.P.
AU - Sozzi, G.
AU - Steele, D.
AU - Stiegler, U.
AU - Stipčević, M.
AU - Stolarczyk, Th
AU - Tareb-Reyes, M.
AU - Taylor, G. N.
AU - Tereshchenko, V.
AU - Toropin, A.
AU - Touchard, A. M.
AU - Tovey, S. N.
AU - Tran, M. T.
AU - Tsesmelis, E.
AU - Ulrichs, J.
AU - Vacavant, L.
AU - Valdata-Nappi, M.
AU - Valuev, V.
AU - Vannucci, F.
AU - Varvell, K. E.
AU - Veltri, M.
AU - Vercesi, V.
AU - Vieira, J. M.
AU - Vinogradova, T.
AU - Weber, F. V.
AU - Weisse, T.
AU - Wilson, F. F.
AU - Winton, L. J.
AU - Yabsley, B. D.
AU - Zaccone, H.
AU - Zuber, K.
AU - Zuccon, P.
PY - 2000/11/6
Y1 - 2000/11/6
N2 - 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.
AB - 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.
KW - Lambda polarization
KW - Neutrino interactions
KW - Nucleon spin
KW - Spin transfer
UR - http://www.scopus.com/inward/record.url?scp=17544397420&partnerID=8YFLogxK
U2 - 10.1016/S0550-3213(00)00503-4
DO - 10.1016/S0550-3213(00)00503-4
M3 - Article
AN - SCOPUS:17544397420
VL - 588
SP - 3
EP - 36
JO - Nuclear Physics B
JF - Nuclear Physics B
SN - 0550-3213
IS - 1-2
ER -