Phys. Rev. D
74,
032001
(2006)
[16 pages]
Search for the Θ+ pentaquark in the reactions γp→K̅ 0K+n and γp→K̅ 0K0p
R. De Vita et al. CLAS Collaboration
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R. De Vita1, M. Battaglieri1, V. Kubarovsky2, N. A. Baltzell3, M. Bellis2,4, J. Goett2, L. Guo5, G. S. Mutchler6, P. Stoler2, M. Ungaro2,7, D. P. Weygand5, M. J. Amaryan34, P. Ambrozewicz17, M. Anghinolfi1, G. Asryan40, H. Avakian5, H. Bagdasaryan34, N. Baillie39, J. P. Ball9, V. Batourine28, I. Bedlinskiy25, N. Benmouna19, B. L. Berman19, A. S. Biselli4,16, S. Boiarinov5, S. Bouchigny23, R. Bradford4, D. Branford15, W. J. Briscoe19, W. K. Brooks5, S. Bültmann34, V. D. Burkert5, C. Butuceanu39, J. R. Calarco31, S. L. Careccia34, D. S. Carman33, S. Chen18, E. Clinton29, P. L. Cole21, P. Collins9, P. Coltharp18, D. Crabb38, H. Crannell12, V. Crede18, J. P. Cummings2, D. Dale41, R. De Masi13, E. De Sanctis22, P. V. Degtyarenko5, A. Deur5, K. V. Dharmawardane34, C. Djalali3, G. E. Dodge34, J. Donnelly20, D. Doughty5,14, M. Dugger9, O. P. Dzyubak3, H. Egiyan5,*, K. S. Egiyan40, L. El Fassi8, L. Elouadrhiri5, P. Eugenio18, G. Fedotov30, H. Funsten39, M. Y. Gabrielyan41, L. Gan42, M. Garçon13, A. Gasparian43, G. Gavalian31,34, G. P. Gilfoyle35, K. L. Giovanetti26, F. X. Girod13, O. Glamazdin27, J. T. Goetz10, E. Golovach30, A. Gonenc17, C. I. O. Gordon20, R. W. Gothe3, K. A. Griffioen39, M. Guidal23, N. Guler34, V. Gyurjyan5, C. Hadjidakis23, K. Hafidi8, H. Hakobyan40, R. S. Hakobyan12, J. Hardie5,14, F. W. Hersman31, K. Hicks33, I. Hleiqawi33, M. Holtrop31, C. E. Hyde-Wright34, Y. Ilieva19, D. G. Ireland20, B. S. Ishkhanov30, E. L. Isupov30, M. M. Ito5, D. Jenkins37, H. S. Jo23, K. Joo7, H. G. Juengst19,†, J. D. Kellie20, M. Khandaker32, W. Kim28, A. Klein34, F. J. Klein12, A. V. Klimenko34, M. Kossov25, L. H. Kramer5,17, J. Kuhn4, S. E. Kuhn34, S. V. Kuleshov25, J. Lachniet4,†, J. M. Laget5,13, J. Langheinrich3, D. Lawrence29, T. Lee31, Ji Li2, K. Livingston20, H. Y. Lu3, M. MacCormick23, N. Markov7, B. McKinnon20, B. A. Mecking5, J. J. Melone20, M. D. Mestayer5, C. A. Meyer4, T. Mibe33, K. Mikhailov25, R. Minehart38, M. Mirazita22, R. Miskimen29, V. Mochalov24, V. Mokeev30, L. Morand13, S. A. Morrow13,23, M. Moteabbed17, P. Nadel-Turonski19, I. Nakagawa44, R. Nasseripour3,17, S. Niccolai23, G. Niculescu26, I. Niculescu26, B. B. Niczyporuk5, M. R. Niroula34, R. A. Niyazov5, M. Nozar5, M. Osipenko1,30, A. I. Ostrovidov18, K. Park28, E. Pasyuk9, C. Paterson20, J. Pierce38, N. Pivnyuk25, D. Pocanic38, O. Pogorelko25, S. Pozdniakov25, J. W. Price10,11, Y. Prok38,‡, D. Protopopescu20, B. A. Raue5,17, G. Riccardi18, G. Ricco1, M. Ripani1, B. G. Ritchie9, F. Ronchetti22, G. Rosner20, P. Rossi22, F. Sabatié13, C. Salgado32, J. P. Santoro5,12, V. Sapunenko5, R. A. Schumacher4, V. S. Serov25, Y. G. Sharabian5, N. V. Shvedunov30, E. S. Smith5, L. C. Smith38, D. I. Sober12, A. Stavinsky25, S. S. Stepanyan28, S. Stepanyan5, B. E. Stokes18, I. I. Strakovsky19, S. Strauch19,§, M. Taiuti1, D. J. Tedeschi3, A. Teymurazyan41, U. Thoma5,**, A. Tkabladze19, S. Tkachenko34, L. Todor35, C. Tur3, M. F. Vineyard36, A. V. Vlassov25, D. P. Watts20,††, L. B. Weinstein34, M. Williams4, E. Wolin5, M. H. Wood3,‡‡, A. Yegneswaran5, L. Zana31, J. Zhang34, B. Zhao7, and Z. Zhao3 (CLAS Collaboration)
1Istituto Nazionale di Fisica Nucleare, Sezione di Genova, and Dipartimento di Fisica, Università di Genova, 16146 Genova, Italy
2Rensselaer Polytechnic Institute, Troy, New York 12180-3590, USA
3University of South Carolina, Columbia, South Carolina 29208, USA
4Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
5Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
6Rice University, Houston, Texas 77005-1892, USA
7University of Connecticut, Storrs, Connecticut 06269, USA
8Argonne National Laboratory
9Arizona State University, Tempe, Arizona 85287-1504, USA
10University of California at Los Angeles, Los Angeles, California 90095-1547, USA
11California State University, Dominguez Hills, California 90747-0005, USA
12Catholic University of America, Washington, D.C. 20064, USA
13CEA-Saclay, Service de Physique Nucléaire, F91191 Gif-sur-Yvette, France
14Christopher Newport University, Newport News, Virginia 23606, USA
15Edinburgh University, Edinburgh EH9 3JZ, United Kingdom
16Fairfield University, Fairfield Connecticut 06824, USA
17Florida International University, Miami, Florida 33199, USA
18Florida State University, Tallahassee, Florida 32306, USA
19The George Washington University, Washington, D.C. 20052, USA
20University of Glasgow, Glasgow G12 8QQ, United Kingdom
21Idaho State University, Pocatello, Idaho 83209, USA
22INFN, Laboratori Nazionali di Frascati, 00044 Frascati, Italy
23Institut de Physique Nucleaire ORSAY, Orsay, France
24Institute for High Energy Physics, Protvino, 142281, Russia
25Institute of Theoretical and Experimental Physics, Moscow, 117259, Russia
26James Madison University, Harrisonburg, Virginia 22807, USA
27Kharkov Institute of Physics and Technology, Kharkov 61108, Ukraine
28Kyungpook National University, Daegu 702-701, South Korea
29University of Massachusetts, Amherst, Massachusetts 01003, USA
30General Nuclear Physics Institute, Moscow State University, 119899 Moscow, Russia
31University of New Hampshire, Durham, New Hampshire 03824-3568, USA
32Norfolk State University, Norfolk, Virginia 23504, USA
33Ohio University, Athens, Ohio 45701, USA
34Old Dominion University, Norfolk, Virginia 23529, USA
35University of Richmond, Richmond, Virginia 23173, USA
36Union College, Schenectady, New York 12308, USA
37Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0435, USA
38University of Virginia, Charlottesville, Virginia 22901, USA
39College of William and Mary, Williamsburg, Virginia 23187-8795, USA
40Yerevan Physics Institute, 375036 Yerevan, Armenia
41University of Kentucky, Lexington, Kentucky 40506, USA
42University of North Carolina, Wilmington, North Carolina 28403, USA
43North Carolina Agricultural and Technical State University, Greensboro, North Carolina 27455, USA
44The Institute of Physical and Chemical Research, RIKEN, Wako, Saitama 351-0198, Japan
Received 27 June 2006; published 1 August 2006
The exclusive reactions γp→K̅ 0K+n and γp→K̅ 0K0p have been studied in the photon energy range 1.6–3.8 GeV, searching for evidence of the exotic baryon Θ+(1540) in the decays Θ+→nK+ and Θ+→pK0. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. The integrated luminosity was about 70 pb-1. The reactions have been isolated by detecting the K+ and proton directly, the neutral kaon via its decay to KS→π+π- and the neutron or neutral kaon via the missing mass technique. The mass and width of known hyperons such as Σ+, Σ- and Λ(1116) were used as a check of the mass determination accuracy and experimental resolution. Approximately 100 000 Λ*(1520)’s and 150 000 ϕ’s were observed in the K̅ 0K+n and K̅ 0K0p final state, respectively. No evidence for the Θ+ pentaquark was found in the nK+ or pKS invariant mass spectra. Upper limits were set on the production cross section of the reaction γp→K̅ 0Θ+ as functions of center-of-mass angle, nK+ and pKS masses. Combining the results of the two reactions, the 95% C.L. upper limit on the total cross section for a resonance peaked at 1540 MeV was found to be 0.7 nb. Within most of the available theoretical models, this corresponds to an upper limit on the Θ+ width, ΓΘ+, ranging between 0.01 and 7 MeV.
© 2006 The American Physical Society
URL:
http://link.aps.org/doi/10.1103/PhysRevD.74.032001
DOI:
10.1103/PhysRevD.74.032001
PACS:
12.39.Mk, 13.60.−r, 13.60.Rj, 14.20.Jn
*Current address: University of NH, Durham, NH 03824-3568, USA †Current address: Old Dominion University, Norfolk, VA 23529, USA ‡Current address: Massachusetts Institute of Technology, Cambridge, MA 02139-4307, USA §Current address: University of SC, Columbia, SC 29208, USA **Current address: Physikalisches Institut der Universität Gießen, 35392 Giessen, Germany ††Current address: Edinburgh University, Edinburgh EH9 3JZ, United Kingdom ‡‡Current address: University of Massachusetts, Amherst, MA 01003, USA
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