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Title: A search for {Sigma}{sup 0}{sub 5}, N{sup 0}{sub 5} and {Theta}{sup ++} pentaquark states.

Abstract

A high-resolution ({sigma}{sub instr.} = 1.5 MeV) search for narrow states ({Lambda} < 10 MeV) with masses of M{sub x} {approx} 1500-1850 MeV in ep {yields} e{prime}K{sup +}X,e{prime}K{sup -}X, and e{prime}{pi}{sup +}X electroproduction at small angles and low Q{sup 2} was performed. These states would be candidate partner states of the reported {Theta}{sup +}(1540) pentaquark. No statistically significant signal was observed in any of the channels at 90% C.L. Upper limits on forward production were determined to be between 0.8% and 4.9% of the {Lambda}(1520) production cross section, depending on the channel and the assumed mass and width of the state.

Authors:
; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC); FOR; National Science Foundation (NSF)
OSTI Identifier:
940684
Report Number(s):
ANL/PHY/JA-57534
Journal ID: ISSN 0556-2813; PRVCAN; TRN: US0807169
DOE Contract Number:
DE-AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Phys. Rev. C; Journal Volume: 75; Journal Issue: 2007
Country of Publication:
United States
Language:
ENGLISH
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CROSS SECTIONS; ELECTROPRODUCTION; MASS; ELECTRON-POSITRON COLLISIONS; DETECTION

Citation Formats

Qiang, Y., Annand, J., Arrington, J., Azimov, Ya. I., Bertozzi, W., Reimer, P., Schulte, E., Zheng, X., Physics, MIT, Univ. of Glasgow, and Nuclear Physics Inst. A search for {Sigma}{sup 0}{sub 5}, N{sup 0}{sub 5} and {Theta}{sup ++} pentaquark states.. United States: N. p., 2007. Web. doi:10.1103/PhysRevC.75.055208.
Qiang, Y., Annand, J., Arrington, J., Azimov, Ya. I., Bertozzi, W., Reimer, P., Schulte, E., Zheng, X., Physics, MIT, Univ. of Glasgow, & Nuclear Physics Inst. A search for {Sigma}{sup 0}{sub 5}, N{sup 0}{sub 5} and {Theta}{sup ++} pentaquark states.. United States. doi:10.1103/PhysRevC.75.055208.
Qiang, Y., Annand, J., Arrington, J., Azimov, Ya. I., Bertozzi, W., Reimer, P., Schulte, E., Zheng, X., Physics, MIT, Univ. of Glasgow, and Nuclear Physics Inst. Mon . "A search for {Sigma}{sup 0}{sub 5}, N{sup 0}{sub 5} and {Theta}{sup ++} pentaquark states.". United States. doi:10.1103/PhysRevC.75.055208.
@article{osti_940684,
title = {A search for {Sigma}{sup 0}{sub 5}, N{sup 0}{sub 5} and {Theta}{sup ++} pentaquark states.},
author = {Qiang, Y. and Annand, J. and Arrington, J. and Azimov, Ya. I. and Bertozzi, W. and Reimer, P. and Schulte, E. and Zheng, X. and Physics and MIT and Univ. of Glasgow and Nuclear Physics Inst.},
abstractNote = {A high-resolution ({sigma}{sub instr.} = 1.5 MeV) search for narrow states ({Lambda} < 10 MeV) with masses of M{sub x} {approx} 1500-1850 MeV in ep {yields} e{prime}K{sup +}X,e{prime}K{sup -}X, and e{prime}{pi}{sup +}X electroproduction at small angles and low Q{sup 2} was performed. These states would be candidate partner states of the reported {Theta}{sup +}(1540) pentaquark. No statistically significant signal was observed in any of the channels at 90% C.L. Upper limits on forward production were determined to be between 0.8% and 4.9% of the {Lambda}(1520) production cross section, depending on the channel and the assumed mass and width of the state.},
doi = {10.1103/PhysRevC.75.055208},
journal = {Phys. Rev. C},
number = 2007,
volume = 75,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • A high-resolution ({sigma}{sub instr.}=1.5 MeV) search for narrow states ({gamma}<10 MeV) with masses of M{sub x}{approx_equal}1500-1850 MeV in ep{yields}e{sup '}K{sup +}X,e{sup '}K{sup -}X, and e{sup '}{pi}{sup +}X electroproduction at small angles and low Q{sup 2} was performed. These states would be candidate partner states of the reported {theta}{sup +}(1540) pentaquark. No statistically significant signal was observed in any of the channels at 90% C.L. Upper limits on forward production were determined to be between 0.8% and 4.9% of the {lambda}(1520) production cross section, depending on the channel and the assumed mass and width of the state.
  • 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 widthmore » 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.« less
  • A high-resolution ({sigma}{sub instr.} = 1.5 MeV) search for narrow states ({Lambda} < 10 MeV) with masses of M{sub x} {approx} 1500-1850 MeV in ep {yields} e' K{sup +} X, e' K{sup -} X and e' {pi}{sup +} X electroproduction at small angles and low Q{sup 2} was performed. These states would be candidate partner states of the reported {Theta}{sup +}(1540) pentaquark. No statistically significant signal was observed in any of the channels at 90% C.L. Upper limits on forward production were determined to be between 0.7% and 4.2% of the {Lambda}(1520) production cross section, depending on the channel andmore » the assumed mass and width of the state.« less
  • The exclusive reaction {gamma}p{yields}K{sup 0}K{sup +}n was studied in the photon energy range between 1.6 and 3.8 GeV searching for evidence of the exotic baryon {theta}{sup +}(1540){yields}nK{sup +}. The decay to nK{sup +} requires the assignment of strangeness S=+1 to any observed resonance. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility corresponding to an integrated luminosity of 70 pb{sup -1}. No evidence for the {theta}{sup +} pentaquark was found. Upper limits were set on the production cross section as function of center-of-mass angle and nK{sup +} mass. The 95% C.L. upper limit on themore » total cross section for a narrow resonance at 1540 MeV was found to be 0.8 nb.« less
  • We search for the charmed pentaquark candidate reported by the H1 collaboration, the {theta}{sub c}(3100){sup 0}, in e{sup +}e{sup -} interactions at a center-of-mass (c.m.) energy of 10.58 GeV, using 124 fb{sup -1} of data recorded with the BABAR detector at the PEP-II e{sup +}e{sup -} facility at SLAC. We find no evidence for such a state in the same pD*{sup -} decay mode reported by H1, and we set limits on its production cross section times branching fraction into pD*{sup -} as a function of c.m. momentum. The corresponding limit on its total rate per e{sup +}e{sup -}{yields}qq event,more » times branching fraction, is about 3 orders of magnitude lower than rates measured for the charmed {lambda}{sub c} and {sigma}{sub c} baryons in such events.« less