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Title: Measurement of the helicity asymmetry E in ω π + π - π 0 photoproduction

Journal Article · · Physical Review C
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The double-polarization observable $$E$$ was studied for the reaction $$\gamma p\to p\omega$$ 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, $$\omega\to\pi^+\pi^-\pi^0$$, using a circularly-polarized tagged-photon beam with energies ranging from the $$\omega$$ 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 sub-threshold $$N(1720)\,3/2^+$$ nucleon resonance. To describe the entire data set, which consisted of $$\omega$$ differential cross sections and a large variety of polarization observables, further contributions from other nucleon resonances were found to be necessary. Here, with respect to non-resonant mechanisms, $$\pi$$ 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 $$W \approx 2$$ GeV.

Research Organization:
Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); George Washington Univ., Washington, DC (United States); Mississippi State Univ., Mississippi State, MS (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Nuclear Physics (NP)
Contributing Organization:
The CLAS Collaboration
Grant/Contract Number:
AC05-06OR23177; SFB/TR110; 16-12-10267; SC0016583; FG02-07ER41528
OSTI ID:
1416533
Alternate ID(s):
OSTI ID: 1416450; OSTI ID: 1439827
Report Number(s):
JLAB-PHY-17-2532; DOE/OR/23177-4227; arXiv:1708.02608; PRVCAN; TRN: US1800954
Journal Information:
Physical Review C, Vol. 96, Issue 6; ISSN 2469-9985
Publisher:
American Physical Society (APS)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 15 works
Citation information provided by
Web of Science

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Cited By (2)

Nucleon resonances in γ p ω p reaction journal December 2019
Polarized ultrashort brilliant multi-GeV $γ$-rays via single-shot laser-electron interaction text January 2019

Figures / Tables (8)