Measurement of the helicity asymmetry e in ω→π+π-π0 photoproduction

The CLAS Collaboration

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

The double-polarization observable E was studied for the reaction γp→pω using the CEBAF Large Acceptance Spectrometer (CLAS) in Hall B at the Thomas Jefferson National Accelerator Facility and the longitudinally polarized frozen-spin target (FROST). The observable was measured from the charged decay mode of the meson, ω→π+π-π0, using a circularly polarized tagged-photon beam with energies ranging from the ω threshold at 1.1 to 2.3 GeV. A partial-wave analysis within the Bonn-Gatchina framework found dominant contributions from the 3/2+ partial wave near threshold, which is identified with the subthreshold N(1720)3/2+ nucleon resonance. To describe the entire data set, which consisted of ω differential cross sections and a large variety of polarization observables, further contributions from other nucleon resonances were found to be necessary. With respect to nonresonant mechanisms, π exchange in the t channel was found to remain small across the analyzed energy range, while Pomeron t-channel exchange gradually grew from the reaction threshold to dominate all other contributions above W≈2 GeV.

Original languageEnglish (US)
Article number065209
JournalPhysical Review C
Volume96
Issue number6
DOIs
StatePublished - Dec 28 2017

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photoproduction
asymmetry
thresholds
photon beams
polarization
acceptability
accelerators
mesons
spectrometers
energy
cross sections
decay

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

Cite this

Measurement of the helicity asymmetry e in ω→π+π-π0 photoproduction. / The CLAS Collaboration.

In: Physical Review C, Vol. 96, No. 6, 065209, 28.12.2017.

Research output: Contribution to journalArticle

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title = "Measurement of the helicity asymmetry e in ω→π+π-π0 photoproduction",
abstract = "The double-polarization observable E was studied for the reaction γp→pω using the CEBAF Large Acceptance Spectrometer (CLAS) in Hall B at the Thomas Jefferson National Accelerator Facility and the longitudinally polarized frozen-spin target (FROST). The observable was measured from the charged decay mode of the meson, ω→π+π-π0, using a circularly polarized tagged-photon beam with energies ranging from the ω threshold at 1.1 to 2.3 GeV. A partial-wave analysis within the Bonn-Gatchina framework found dominant contributions from the 3/2+ partial wave near threshold, which is identified with the subthreshold N(1720)3/2+ nucleon resonance. To describe the entire data set, which consisted of ω differential cross sections and a large variety of polarization observables, further contributions from other nucleon resonances were found to be necessary. With respect to nonresonant mechanisms, π exchange in the t channel was found to remain small across the analyzed energy range, while Pomeron t-channel exchange gradually grew from the reaction threshold to dominate all other contributions above W≈2 GeV.",
author = "{The CLAS Collaboration} and Z. Akbar and P. Roy and S. Park and V. Crede and Anisovich, {A. V.} and I. Denisenko and E. Klempt and Nikonov, {V. A.} and Sarantsev, {A. V.} and Adhikari, {K. P.} and S. Adhikari and Amaryan, {M. J.} and {Anefalos Pereira}, S. and H. Avakian and J. Ball and M. Battaglieri and V. Batourine and I. Bedlinskiy and S. Boiarinov and Briscoe, {W. J.} and J. Brock and Brooks, {W. K.} and Burkert, {V. D.} and Cao, {F. T.} and C. Carlin and Carman, {D. S.} and A. Celentano and G. Charles and T. Chetry and G. Ciullo and L. Clark and Cole, {P. L.} and M. Contalbrigo and O. Cortes and A. D'Angelo and N. Dashyan and {De Vita}, R. and {De Sanctis}, E. and A. Deur and C. Djalali and Michael Dugger and R. Dupre and H. Egiyan and {El Fassi}, L. and P. Eugenio and G. Fedotov and R. Fersch and A. Filippi and A. Fradi and Barry Ritchie",
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AU - The CLAS Collaboration

AU - Akbar, Z.

AU - Roy, P.

AU - Park, S.

AU - Crede, V.

AU - Anisovich, A. V.

AU - Denisenko, I.

AU - Klempt, E.

AU - Nikonov, V. A.

AU - Sarantsev, A. V.

AU - Adhikari, K. P.

AU - Adhikari, S.

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AU - Briscoe, W. J.

AU - Brock, J.

AU - Brooks, W. K.

AU - Burkert, V. D.

AU - Cao, F. T.

AU - Carlin, C.

AU - Carman, D. S.

AU - Celentano, A.

AU - Charles, G.

AU - Chetry, T.

AU - Ciullo, G.

AU - Clark, L.

AU - Cole, P. L.

AU - Contalbrigo, M.

AU - Cortes, O.

AU - D'Angelo, A.

AU - Dashyan, N.

AU - De Vita, R.

AU - De Sanctis, E.

AU - Deur, A.

AU - Djalali, C.

AU - Dugger, Michael

AU - Dupre, R.

AU - Egiyan, H.

AU - El Fassi, L.

AU - Eugenio, P.

AU - Fedotov, G.

AU - Fersch, R.

AU - Filippi, A.

AU - Fradi, A.

AU - Ritchie, Barry

PY - 2017/12/28

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N2 - The double-polarization observable E was studied for the reaction γp→pω using the CEBAF Large Acceptance Spectrometer (CLAS) in Hall B at the Thomas Jefferson National Accelerator Facility and the longitudinally polarized frozen-spin target (FROST). The observable was measured from the charged decay mode of the meson, ω→π+π-π0, using a circularly polarized tagged-photon beam with energies ranging from the ω threshold at 1.1 to 2.3 GeV. A partial-wave analysis within the Bonn-Gatchina framework found dominant contributions from the 3/2+ partial wave near threshold, which is identified with the subthreshold N(1720)3/2+ nucleon resonance. To describe the entire data set, which consisted of ω differential cross sections and a large variety of polarization observables, further contributions from other nucleon resonances were found to be necessary. With respect to nonresonant mechanisms, π exchange in the t channel was found to remain small across the analyzed energy range, while Pomeron t-channel exchange gradually grew from the reaction threshold to dominate all other contributions above W≈2 GeV.

AB - The double-polarization observable E was studied for the reaction γp→pω using the CEBAF Large Acceptance Spectrometer (CLAS) in Hall B at the Thomas Jefferson National Accelerator Facility and the longitudinally polarized frozen-spin target (FROST). The observable was measured from the charged decay mode of the meson, ω→π+π-π0, using a circularly polarized tagged-photon beam with energies ranging from the ω threshold at 1.1 to 2.3 GeV. A partial-wave analysis within the Bonn-Gatchina framework found dominant contributions from the 3/2+ partial wave near threshold, which is identified with the subthreshold N(1720)3/2+ nucleon resonance. To describe the entire data set, which consisted of ω differential cross sections and a large variety of polarization observables, further contributions from other nucleon resonances were found to be necessary. With respect to nonresonant mechanisms, π exchange in the t channel was found to remain small across the analyzed energy range, while Pomeron t-channel exchange gradually grew from the reaction threshold to dominate all other contributions above W≈2 GeV.

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