Phys. Rev. Lett.
90,
131804
(2003)
[6 pages]
First Measurement of Transferred Polarization in the Exclusive e⃗p→e′K+Λ⃗ Reaction
D. S. Carman et al. CLAS Collaboration
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D. S. Carman1, K. Joo2,3, M. D. Mestayer2, B. A. Raue4,2, G. Adams31, P. Ambrozewicz4, E. Anciant6, M. Anghinolfi19, D. S. Armstrong37, B. Asavapibhop25, G. Audit6, T. Auger6, H. Avakian18, H. Bagdasaryan38, J. P. Ball5, S. P. Barrow14, M. Battaglieri19, K. Beard22, M. Bektasoglu29,1, M. Bellis31, C. Bennhold15, N. Bianchi18, A. S. Biselli31, S. Boiarinov21, B. E. Bonner32, S. Bouchigny20,2, R. Bradford8, D. Branford13, W. J. Briscoe15, W. K. Brooks2, V. D. Burkert2, C. Butuceanu37, J. R. Calarco27, B. Carnahan9, A. Cazes34, C. Cetina15, L. Ciciani29, R. Clark8, P. L. Cole35,2, A. Coleman37, D. Cords2, P. Corvisiero19, D. Crabb3, H. Crannell9, J. P. Cummings31, E. DeSanctis18, P. V. Degtyarenko2, H. Denizli30, L. Dennis14, R. DeVita19, K. V. Dharmawardane29, K. S. Dhuga15, C. Djalali34, G. E. Dodge29, D. Doughty10,2, P. Dragovitsch14, M. Dugger5, S. Dytman30, O. P. Dzyubak34, M. Eckhause37, H. Egiyan37, K. S. Egiyan38, L. Elouadrhiri10,2, A. Empl31, P. Eugenio14, R. Fatemi3, G. Fedotov26, R. J. Feuerbach8, J. Ficenec36, T. A. Forest29, H. Funsten37, S. J. Gaff12, M. Gai11, M. Garçon6, G. Gavalian27,38, S. Gilad24, G. P. Gilfoyle33, K. L. Giovanetti22, P. Girard34, E. Golovach26, C. I. O. Gordon16, K. Griffioen37, S. Grimes1, M. Guidal20, M. Guillo34, L. Guo2, V. Gyurjyan2, C. Hadjidakis20, R. S. Hakobyan9, J. Hardie10,2, D. Heddle2,10, P. Heimberg15, F. W. Hersman27, K. Hicks1, R. S. Hicks25, M. Holtrop27, J. Hu31, C. E. Hyde-Wright29, B. Ishkhanov26, M. M. Ito2, D. Jenkins36, J. H. Kelley12, J. D. Kellie16, M. Khandaker28, K. Y. Kim30, K. Kim23, W. Kim23, A. Klein29, F. J. Klein9,2, A. V. Klimenko29, M. Klusman31, M. Kossov21, L. H. Kramer4,2, Y. Kuang37, S. E. Kuhn29, J. Kuhn31, J. Lachniet8, J. M. Laget6, D. Lawrence25, J. Li31, K. Livingston16, A. Longhi9, K. Lukashin2, J. J. Manak2, C. Marchand6, T. Mart17,15, S. McAleer14, J. McCarthy3, J. W. C. McNabb8, B. A. Mecking2, S. Mehrabyan30, J. J. Melone16, C. A. Meyer8, K. Mikhailov21, R. Minehart3, M. Mirazita18, R. Miskimen25, V. Mokeev26, L. Morand6, S. A. Morrow20, M. U. Mozer1, V. Muccifora18, J. Mueller30, L. Y. Murphy15, G. S. Mutchler32, J. Napolitano31, R. Nasseripour4, S. O. Nelson12, S. Niccolai15, G. Niculescu1, I. Niculescu15, B. B. Niczyporuk2, R. A. Niyazov29, M. Nozar2,28, G. V. O’Rielly15, A. K. Opper1, M. Osipenko26, K. Park23, K. Paschke8, E. Pasyuk5, G. Peterson25, N. Pivnyuk21, D. Pocanic3, O. Pogorelko21, E. Polli18, S. Pozdniakov21, B. M. Preedom34, J. W. Price7, Y. Prok3, D. Protopopescu27, L. M. Qin29, G. Riccardi14, G. Ricco19, M. Ripani19, B. G. Ritchie5, F. Ronchetti18, P. Rossi18, D. Rowntree24, P. Rubin33, F. Sabatié6,29, K. Sabourov12, C. Salgado28, J. Santoro36,2, V. Sapunenko19, R. A. Schumacher8, V. S. Serov21, Y. G. Sharabian2,38, J. Shaw25, S. Simionatto15, A. V. Skabelin24, E. S. Smith2, L. C. Smith3, D. I. Sober9, M. Spraker12, A. Stavinsky21, S. Stepanyan29,2, P. Stoler31, M. Taiuti19, S. Taylor32, D. J. Tedeschi34, U. Thoma2, R. Thompson30, L. Todor8, C. Tur34, M. Ungaro31, M. F. Vineyard33, A. V. Vlassov21, K. Wang3, L. B. Weinstein29, H. Weller12, D. P. Weygand2, C. S. Whisnant34, E. Wolin2, M. H. Wood34, A. Yegneswaran2, J. Yun29, B. Zhang24, J. Zhao24, and Z. Zhou24 (CLAS Collaboration)
1Ohio University, Athens, Ohio 45701
2Thomas Jefferson National Accelerator Laboratory, Newport News, Virginia 23606
3University of Virginia, Charlottesville, Virginia 22901
4Florida International University, Miami, Florida 33199
5Arizona State University, Tempe, Arizona 85287
6CEA-Saclay, DAPNIA-SPhN, F91191 Gif-sur-Yvette Cedex, France
7University of California at Los Angeles, Los Angeles, California 90095
8Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
9Catholic University of America, Washington, D.C. 20064
10Christopher Newport University, Newport News, Virginia 23606
11University of Connecticut, Storrs, Connecticut 06269
12Duke University, Durham, North Carolina 27708
13Edinburgh University, Edinburgh EH9 3JZ, United Kingdom
14Florida State University, Tallahassee, Florida 32306
15The George Washington University, Washington, D.C. 20052
16University of Glasgow, Glasgow G12 8QQ, United Kingdom
17Jurusan Fisika, FMIPA, Universitas Indonesia, Depok 16424, Indonesia
18INFN, Laboratori Nazionali di Frascati, P.O. 13,00044 Frascati, Italy
19INFN, Sezione di Genova and Dipartimento di Fisica, Università di Genova, 16146 Genova, Italy
20Institut de Physique Nucleaire d’ORSAY, IN2P3, BP1, 91406 Orsay, France
21Institute of Theoretical and Experimental Physics, Moscow, 117259, Russia
22James Madison University, Harrisonburg, Virginia 22807
23Kyungpook National University, Taegu 702-701, South Korea
24Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
25University of Massachusetts, Amherst, Massachusetts 01003
26Moscow State University, 119899 Moscow, Russia
27University of New Hampshire, Durham, New Hampshire 03824
28Norfolk State University, Norfolk, Virginia 23504
29Old Dominion University, Norfolk, Virginia 23529
30University of Pittsburgh, Pittsburgh, Pennsylvania 15260
31Rensselaer Polytechnic Institute, Troy, New York 12180
32Rice University, Houston, Texas 77005
33University of Richmond, Richmond, Virginia 23173
34University of South Carolina, Columbia, South Carolina 29208
35University of Texas at El Paso, El Paso, Texas 79968
36Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
37College of William and Mary, Williamsburg, Virginia 23187
38Yerevan Physics Institute, 375036 Yerevan, Armenia
Received 4 December 2002; published 4 April 2003
The first measurements of the transferred polarization for the exclusive e⃗p→e′K+Λ⃗ reaction have been performed at Jefferson Laboratory using the CLAS spectrometer. A 2.567 GeV beam was used to measure the hyperon polarization over Q2 from 0.3 to 1.5 (GeV/c)2, W from 1.6 to 2.15 GeV, and over the full K+ center-of-mass angular range. Comparison with predictions of hadrodynamic models indicates strong sensitivity to the underlying resonance contributions. A nonrelativistic quark-model interpretation of our data suggests that the ss̅ quark pair is produced with spins predominantly antialigned. Implications for the validity of the most widely used quark-pair creation operator are discussed.
© 2003 The American Physical Society
URL:
http://link.aps.org/doi/10.1103/PhysRevLett.90.131804
DOI:
10.1103/PhysRevLett.90.131804
PACS:
13.60.Rj, 13.88.+e, 14.20.Jn, 14.40.Aq
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