Search for the {theta}{sup +} pentaquark in the reactions {gamma}p{yields}K{sup 0}K{sup +}n and {gamma}p{yields}K{sup 0}K{sup 0}p

Journal Article · Tue Aug 01 04:00:00 EDT 2006 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.74.032001· OSTI ID:20869208

De Vita, R; Battaglieri, M; Anghinolfi, M; Ricco, G; Ripani, M; Taiuti, M ^[1]; Kubarovsky, V; Goett, J; Stoler, P; Cummings, J P; Li, Ji ^[2]; Baltzell, N A; Djalali, C; Dzyubak, O P; Gothe, R W; Langheinrich, J; Lu, H Y; Tedeschi, D J; Tur, C; Wood, M H ^[3]

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1. Istituto Nazionale di Fisica Nucleare, Sezione di Genova, and Dipartimento di Fisica, Universita di Genova, 16146 Genova (Italy)
2. Rensselaer Polytechnic Institute, Troy, New York 12180-3590 (United States)
3. University of South Carolina, Columbia, South Carolina 29208 (United States)

The exclusive reactions {gamma}p{yields}K{sup 0}K{sup +}n and {gamma}p{yields}K{sup 0}K{sup 0}p have been studied in the photon energy range 1.6-3.8 GeV, searching for evidence of the exotic baryon {theta}{sup +}(1540) in the decays {theta}{sup +}{yields}nK{sup +} and {theta}{sup +}{yields}pK{sup 0}. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. The integrated luminosity was about 70 pb{sup -1}. The reactions have been isolated by detecting the K{sup +} and proton directly, the neutral kaon via its decay to K{sub S}{yields}{pi}{sup +}{pi}{sup -} and the neutron or neutral kaon via the missing mass technique. The mass and width of known hyperons such as {sigma}{sup +}, {sigma}{sup -} and {lambda}(1116) were used as a check of the mass determination accuracy and experimental resolution. Approximately 100 000 {lambda}*(1520)'s and 150 000 {phi}'s were observed in the K{sup 0}K{sup +}n and K{sup 0}K{sup 0}p final state, respectively. No evidence for the {theta}{sup +} pentaquark was found in the nK{sup +} or pK{sub S} invariant mass spectra. Upper limits were set on the production cross section of the reaction {gamma}p{yields}K{sup 0}{theta}{sup +} as functions of center-of-mass angle, nK{sup +} and pK{sub S} 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 {theta}{sup +} width, {gamma}{sub {theta}{sup +}}, ranging between 0.01 and 7 MeV.

• OSTI ID: 20869208
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 3 Vol. 74; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ACCURACY
CEBAF ACCELERATOR
GEV RANGE
KAONS NEUTRAL
KAONS PLUS
LAMBDA BARYONS
MASS SPECTRA
MEV RANGE
MISSING MASS
MULTIPARTICLE SPECTROMETERS
NEUTRONS
PARTICLE DECAY
PARTICLE IDENTIFICATION
PHOTONS
PIONS MINUS
PIONS PLUS
PROTONS
SIGMA MINUS PARTICLES
SIGMA PLUS PARTICLES
TOTAL CROSS SECTIONS