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Title: Differential cross sections and recoil polarizations for the reaction γpK+Σ0

Here, high-statistics measurements of differential cross sections and recoil polarizations for the reaction $$\gamma p \rightarrow K^+ \Sigma^0$$ have been obtained using the CLAS detector at Jefferson Lab. We cover center-of-mass energies ($$\sqrt{s}$$) from 1.69 to 2.84 GeV, with an extensive coverage in the $K^+$ production angle. Independent measurements were made using the $$K^{+}p\pi^{-}$$($$\gamma$$) and $$K^{+}p$$($$\pi^-,\gamma$$) final-state topologies, and were found to exhibit good agreement. Our differential cross sections show good agreement with earlier CLAS, SAPHIR and LEPS results, while offering better statistical precision and a 300-MeV increase in $$\sqrt{s}$$ coverage. Above $$\sqrt{s} \approx 2.5$$ GeV, $t$- and $u$-channel Regge scaling behavior can be seen at forward- and backward-angles, respectively. Our recoil polarization ($$P_\Sigma$$) measurements represent a substantial increase in kinematic coverage and enhanced precision over previous world data. At forward angles we find that $$P_\Sigma$$ is of the same magnitude but opposite sign as $$P_\Lambda$$, in agreement with the static SU(6) quark model prediction of $$P_\Sigma \approx -P_\Lambda$$. This expectation is violated in some mid- and backward-angle kinematic regimes, where $$P_\Sigma$$ and $$P_\Lambda$$ are of similar magnitudes but also have the same signs. In conjunction with several other meson photoproduction results recently published by CLAS, the present data will help constrain the partial wave analyses being performed to search for missing baryon resonances.
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Publication Date:
OSTI Identifier:
986375
Report Number(s):
JLAB-PHY--10-1183; DOE/OR/23177--1223; arXiv:1006.0374
Journal ID: ISSN 0556-2813; PRVCAN; TRN: US1006339
Grant/Contract Number:
AC05-06OR23177
Type:
Accepted Manuscript
Journal Name:
Physical Review. C, Nuclear Physics
Additional Journal Information:
Journal Volume: 82; Journal Issue: 2; Journal ID: ISSN 0556-2813
Publisher:
American Physical Society (APS)
Research Org:
Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ACCURACY; BARYONS; DIFFERENTIAL CROSS SECTIONS; FORECASTING; MESONS; PARTIAL WAVES; PHOTOPRODUCTION; POLARIZATION; PRODUCTION; QUARK MODEL; U CHANNEL