Abstract
In the Standard Model, b quarks produced in e+e- annihilation at the Z0 peak have a large average longitudinal polarization of -0.94. Some fraction of this polarization is expected to be transferred to b-flavored baryons during hadronization. The average longitudinal polarization of weakly decaying b baryons, 〈PΛbL〉, is measured in approximately 4.3 million hadronic Z0 decays collected with the OPAL detector between 1990 and 1995 at LEP. Those b baryons that decay semileptonically and produce a Λ baryon are identified through the correlation of the baryon number of the Λ and the electric charge of the lepton. In this semileptonic decay, the ratio of the neutrino energy to the lepton energy is a sensitive polarization observable. The neutrino energy is estimated using missing energy measurements. From a fit to the distribution of this ratio, the value 〈PΛbL〉 = -0.56+0.20-0.13 ± 0.09 is obtained, where the first error is statistical and the second systematic.
| Original language | English |
|---|---|
| Pages (from-to) | 539-554 |
| Number of pages | 16 |
| Journal | Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics |
| Volume | 444 |
| Issue number | 3-4 |
| DOIs | |
| Publication status | Published - 1998 Dec 24 |
| Externally published | Yes |
ASJC Scopus subject areas
- Nuclear and High Energy Physics
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In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, Vol. 444, No. 3-4, 24.12.1998, p. 539-554.
Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Measurement of the average polarization of b baryons in hadronic Z0 decays
AU - Abbiendi, G.
AU - Ackerstaff, K.
AU - Alexander, G.
AU - Allison, J.
AU - Altekamp, N.
AU - Anderson, K. J.
AU - Anderson, S.
AU - Arcelli, S.
AU - Asai, S.
AU - Ashby, S. F.
AU - Axen, D.
AU - Azuelos, G.
AU - Ball, A. H.
AU - Barberio, E.
AU - Barlow, R. J.
AU - Bartoldus, R.
AU - Batley, J. R.
AU - Baumann, S.
AU - Bechtluft, J.
AU - Behnke, T.
AU - Bell, K. W.
AU - Bella, G.
AU - Bellerive, A.
AU - Bentvelsen, S.
AU - Bethke, S.
AU - Betts, S.
AU - Biebel, O.
AU - Biguzzi, A.
AU - Bird, S. D.
AU - Blobel, V.
AU - Bloodworth, I. J.
AU - Bobinski, M.
AU - Bock, P.
AU - Böhme, J.
AU - Bonacorsi, D.
AU - Boutemeur, M.
AU - Braibant, S.
AU - Bright-Thomas, P.
AU - Brigliadori, L.
AU - Brown, R. M.
AU - Burckhart, H. J.
AU - Burgard, C.
AU - Bürgin, R.
AU - Capiluppi, P.
AU - Carnegie, R. K.
AU - Carter, A. A.
AU - Carter, J. R.
AU - Chang, C. Y.
AU - Charlton, D. G.
AU - Chrisman, D.
AU - Ciocca, C.
AU - Clarke, P. E.L.
AU - Clay, E.
AU - Cohen, I.
AU - Conboy, J. E.
AU - Cooke, O. C.
AU - Couyoumtzelis, C.
AU - Coxe, R. L.
AU - Cuffiani, M.
AU - Dado, S.
AU - Dallavalle, G. M.
AU - Davis, R.
AU - de Jong, S.
AU - del Pozo, L. A.
AU - de Roeck, A.
AU - Desch, K.
AU - Dienes, B.
AU - Dixit, M. S.
AU - Dubbert, J.
AU - Duchovni, E.
AU - Duckeck, G.
AU - Duerdoth, I. P.
AU - Eatough, D.
AU - Estabrooks, P. G.
AU - Etzion, E.
AU - Evans, H. G.
AU - Fabbri, F.
AU - Fanti, M.
AU - Faust, A. A.
AU - Fiedler, F.
AU - Fierro, M.
AU - Fleck, I.
AU - Folman, R.
AU - Fürtjes, A.
AU - Futyan, D. I.
AU - Gagnon, P.
AU - Gary, J. W.
AU - Gascon, J.
AU - Gascon-Shotkin, S. M.
AU - Gaycken, G.
AU - Geich-Gimbel, C.
AU - Giacomelli, G.
AU - Giacomelli, P.
AU - Gibson, V.
AU - Gibson, W. R.
AU - Gingrich, D. M.
AU - Glenzinski, D.
AU - Goldberg, J.
AU - Gorn, W.
AU - Grandi, C.
AU - Gross, E.
AU - Grunhaus, J.
AU - Gruwé, M.
AU - Hanson, G. G.
AU - Hansroul, M.
AU - Hapke, M.
AU - Harder, K.
AU - Hargrove, C. K.
AU - Hartmann, C.
AU - Hauschild, M.
AU - Hawkes, C. M.
AU - Hawkings, R.
AU - Hemingway, R. J.
AU - Herndon, M.
AU - Herten, G.
AU - Heuer, R. D.
AU - Hildreth, M. D.
AU - Hill, J. C.
AU - Hillier, S. J.
AU - Hobson, P. R.
AU - Hocker, A.
AU - Homer, R. J.
AU - Honma, A. K.
AU - Horváth, D.
AU - Hossain, K. R.
AU - Howard, R.
AU - Hüntemeyer, P.
AU - Igo-Kemenes, P.
AU - Imrie, D. C.
AU - Ishii, K.
AU - Jacob, F. R.
AU - Jawahery, A.
AU - Jeremie, H.
AU - Jimack, M.
AU - Jones, C. R.
AU - Jovanovic, P.
AU - Junk, T. R.
AU - Karlen, D.
AU - Kartvelishvili, V.
AU - Kawagoe, K.
AU - Kawamoto, T.
AU - Kayal, P. I.
AU - Keeler, R. K.
AU - Kellogg, R. G.
AU - Kennedy, B. W.
AU - Klier, A.
AU - Kluth, S.
AU - Kobayashi, T.
AU - Kobel, M.
AU - Koetke, D. S.
AU - Kokott, T. P.
AU - Kolrep, M.
AU - Komamiya, S.
AU - Kowalewski, R. V.
AU - Kress, T.
AU - Krieger, P.
AU - von Krogh, J.
AU - Kuhl, T.
AU - Kyberd, P.
AU - Lafferty, G. D.
AU - Lanske, D.
AU - Lauber, J.
AU - Lautenschlager, S. R.
AU - Lawson, I.
AU - Layter, J. G.
AU - Lazic, D.
AU - Lee, A. M.
AU - Lellouch, D.
AU - Letts, J.
AU - Levinson, L.
AU - Liebisch, R.
AU - List, B.
AU - Littlewood, C.
AU - Lloyd, A. W.
AU - Lloyd, S. L.
AU - Loebinger, F. K.
AU - Long, G. D.
AU - Losty, M. J.
AU - Ludwig, J.
AU - Liu, D.
AU - Macchiolo, A.
AU - Macpherson, A.
AU - Mader, W.
AU - Mannelli, M.
AU - Marcellini, S.
AU - Markopoulos, C.
AU - Martin, A. J.
AU - Martin, J. P.
AU - Martinez, G.
AU - Mashimo, T.
AU - Mättig, P.
AU - McDonald, W. J.
AU - McKenna, J.
AU - Mckigney, E. A.
AU - McMahon, T. J.
AU - McPherson, R. A.
AU - Meijers, F.
AU - Menke, S.
AU - Merritt, F. S.
AU - Mes, H.
AU - Meyer, J.
AU - Michelini, A.
AU - Mihara, S.
AU - Mikenberg, G.
AU - Miller, D. J.
AU - Mir, R.
AU - Mohr, W.
AU - Montanari, A.
AU - Mori, T.
AU - Nagai, K.
AU - Nakamura, I.
AU - Neal, H. A.
AU - Nellen, B.
AU - Nisius, R.
AU - O'Neale, S. W.
AU - Oakham, F. G.
AU - Odorici, F.
AU - Ogren, H. O.
AU - Oreglia, M. J.
AU - Orito, S.
AU - Pálinkás, J.
AU - Pásztor, G.
AU - Pater, J. R.
AU - Patrick, G. N.
AU - Patt, J.
AU - Perez-Ochoa, R.
AU - Petzold, S.
AU - Pfeifenschneider, P.
AU - Pilcher, J. E.
AU - Pinfold, J.
AU - Plane, D. E.
AU - Poffenberger, P.
AU - Polok, J.
AU - Przybycień, M.
AU - Rembser, C.
AU - Rick, H.
AU - Robertson, S.
AU - Robins, S. A.
AU - Rodning, N.
AU - Roney, J. M.
AU - Roscoe, K.
AU - Rossi, A. M.
AU - Rozen, Y.
AU - Runge, K.
AU - Runolfsson, O.
AU - Rust, D. R.
AU - Sachs, K.
AU - Saeki, T.
AU - Sahr, O.
AU - Sang, W. M.
AU - Sarkisyan, E. K.G.
AU - Sbarra, C.
AU - Schaile, A. D.
AU - Schaile, O.
AU - Scharf, F.
AU - Scharff-Hansen, P.
AU - Schieck, J.
AU - Schmitt, B.
AU - Schmitt, S.
AU - Schöning, A.
AU - Schröder, M.
AU - Schumacher, M.
AU - Schwick, C.
AU - Scott, W. G.
AU - Seuster, R.
AU - Shears, T. G.
AU - Shen, B. C.
AU - Shepherd-Themistocleous, C. H.
AU - Sherwood, P.
AU - Siroli, G. P.
AU - Sittler, A.
AU - Skuja, A.
AU - Smith, A. M.
AU - Snow, G. A.
AU - Sobie, R.
AU - Söldner-Rembold, S.
AU - Sproston, M.
AU - Stahl, A.
AU - Stephens, K.
AU - Steuerer, J.
AU - Stoll, K.
AU - Strom, D.
AU - Ströhmer, R.
AU - Surrow, B.
AU - Talbot, S. D.
AU - Tanaka, S.
AU - Taras, P.
AU - Tarem, S.
AU - Teuscher, R.
AU - Thiergen, M.
AU - Thomson, M. A.
AU - von Törne, E.
AU - Torrence, E.
AU - Towers, S.
AU - Trigger, I.
AU - Trócsányi, Z.
AU - Tsur, E.
AU - Turcot, A. S.
AU - Turner-Watson, M. F.
AU - van Kooten, R.
AU - Vannerem, P.
AU - Verzocchi, M.
AU - Voss, H.
AU - Wäckerle, F.
AU - Wagner, A.
AU - Ward, C. P.
AU - Ward, D. R.
AU - Watkins, P. M.
AU - Watson, A. T.
AU - Watson, N. K.
AU - Wells, P. S.
AU - Wermes, N.
AU - White, J. S.
AU - Wilson, G. W.
AU - Wilson, J. A.
AU - Wyatt, T. R.
AU - Yamashita, S.
AU - Yekutieli, G.
AU - Zacek, V.
AU - Zer-Zion, D.
N1 - Funding Information: We thank M. Jeżabek for providing the Fortran program of the calculations of the neutrino and lepton spectra as described in Ref. [10] . We particularly wish to thank the SL Division for the efficient operation of the LEP accelerator at all energies and for their continuing close cooperation with our experimental group. We thank our colleagues from CEA, DAPNIA/SPP, CE-Saclay for their efforts over the years on the time-of-flight and trigger systems which we continue to use. In addition to the support staff at our own institutions we are pleased to acknowledge the Department of Energy, USA; National Science Foundation, USA; Particle Physics and Astronomy Research Council, UK; Natural Sciences and Engineering Research Council, Canada; Israel Science Foundation, administered by the Israel Academy of Science and Humanities; Minerva Gesellschaft; Benoziyo Center for High Energy Physics; Japanese Ministry of Education, Science and Culture (the Monbusho) and a grant under the Monbusho International Science Research Program; German Israeli Bi-national Science Foundation (GIF); Bundesministerium für Bildung, Wissenschaft, Forschung und Technologie, Germany; National Research Council of Canada; Research Corporation, USA; Hungarian Foundation for Scientific Research, OTKA T-016660, T023793 and OTKA F-023259.
PY - 1998/12/24
Y1 - 1998/12/24
N2 - In the Standard Model, b quarks produced in e+e- annihilation at the Z0 peak have a large average longitudinal polarization of -0.94. Some fraction of this polarization is expected to be transferred to b-flavored baryons during hadronization. The average longitudinal polarization of weakly decaying b baryons, 〈PΛbL〉, is measured in approximately 4.3 million hadronic Z0 decays collected with the OPAL detector between 1990 and 1995 at LEP. Those b baryons that decay semileptonically and produce a Λ baryon are identified through the correlation of the baryon number of the Λ and the electric charge of the lepton. In this semileptonic decay, the ratio of the neutrino energy to the lepton energy is a sensitive polarization observable. The neutrino energy is estimated using missing energy measurements. From a fit to the distribution of this ratio, the value 〈PΛbL〉 = -0.56+0.20-0.13 ± 0.09 is obtained, where the first error is statistical and the second systematic.
AB - In the Standard Model, b quarks produced in e+e- annihilation at the Z0 peak have a large average longitudinal polarization of -0.94. Some fraction of this polarization is expected to be transferred to b-flavored baryons during hadronization. The average longitudinal polarization of weakly decaying b baryons, 〈PΛbL〉, is measured in approximately 4.3 million hadronic Z0 decays collected with the OPAL detector between 1990 and 1995 at LEP. Those b baryons that decay semileptonically and produce a Λ baryon are identified through the correlation of the baryon number of the Λ and the electric charge of the lepton. In this semileptonic decay, the ratio of the neutrino energy to the lepton energy is a sensitive polarization observable. The neutrino energy is estimated using missing energy measurements. From a fit to the distribution of this ratio, the value 〈PΛbL〉 = -0.56+0.20-0.13 ± 0.09 is obtained, where the first error is statistical and the second systematic.
UR - http://www.scopus.com/inward/record.url?scp=0345918581&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0345918581&partnerID=8YFLogxK
U2 - 10.1016/S0370-2693(98)01387-2
DO - 10.1016/S0370-2693(98)01387-2
M3 - Article
AN - SCOPUS:0345918581
SN - 0370-2693
VL - 444
SP - 539
EP - 554
JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
IS - 3-4
ER -