Search for the Θ+ pentaquark in the reactions γp→K¯¯¯0K+n and γp→K¯¯¯0K0p

R. DeVita; Angela Biselli

doi:10.1103/PhysRevD.74.032001

Search for the Θ+ pentaquark in the reactions γp→K¯¯¯0K+n and γp→K¯¯¯0K0p

R. DeVita, Angela Biselli

Fairfield University

Research output: Contribution to journal › Article › peer-review

Abstract

<p> The exclusive reactions γp→K0K+n and γp→KOK0p 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&lowast;(1520)’s and 150 000 ϕ’s were observed in the K0K+n and K0K0p 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→K0Θ+ 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.</p>

Original language	American English
Journal	Physical Review D
Volume	74
DOIs	https://doi.org/10.1103/PhysRevD.74.032001
State	Published - Jan 1 2006

Disciplines

Physical Sciences and Mathematics
Physics

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Search for the pentaquark in the reactions p K 0K n and p Final published version, 0.98 MBLicense: CC BY

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@article{59629d8ed1ee4b5f9fdf116a46b60d26,

title = "Search for the Θ+ pentaquark in the reactions γp→K¯¯¯0K+n and γp→K¯¯¯0K0p",

abstract = " The exclusive reactions \γp\→K0K+n and \γp\→KOK0p 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\&lowast;(1520)\’s and 150\ 000 \ϕ\’s were observed in the K0K+n and K0K0p 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\→K0\Θ+ 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, \Γ\Θ+, ranging between 0.01 and 7 MeV.",

author = "R. DeVita and Angela Biselli",

year = "2006",

month = jan,

day = "1",

doi = "10.1103/PhysRevD.74.032001",

language = "American English",

volume = "74",

journal = "Physical Review D",

}

TY - JOUR

T1 - Search for the Θ+ pentaquark in the reactions γp→K¯¯¯0K+n and γp→K¯¯¯0K0p

AU - DeVita, R.

AU - Biselli, Angela

PY - 2006/1/1

Y1 - 2006/1/1

N2 - The exclusive reactions γp→K0K+n and γp→KOK0p 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&lowast;(1520)’s and 150 000 ϕ’s were observed in the K0K+n and K0K0p 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→K0Θ+ 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.

AB - The exclusive reactions γp→K0K+n and γp→KOK0p 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&lowast;(1520)’s and 150 000 ϕ’s were observed in the K0K+n and K0K0p 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→K0Θ+ 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.

UR - https://digitalcommons.fairfield.edu/physics-facultypubs/73

U2 - 10.1103/PhysRevD.74.032001

DO - 10.1103/PhysRevD.74.032001

M3 - Article

VL - 74

JO - Physical Review D

JF - Physical Review D

ER -

Search for the Θ+ pentaquark in the reactions γp→K¯¯¯0K+n and γp→K¯¯¯0K0p

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