Measurement of the beam spin asymmetry of e→p→e′p′η in the deep-inelastic regime with CLAS
Chiral-odd generalized parton distributions, CLAS collaboration, Deeply Virtual Meson Production, Nucleon structure
© 2019 The Authors The beam spin asymmetry of the exclusive pseudoscalar channel e→p→e′p′η was measured for the first time in the deep-inelastic regime (W>2 GeV/c2 and Q2>1 GeV2/c2) using a longitudinally polarized 5.78 GeV electron beam at Jefferson Lab with the CEBAF Large Acceptance Spectrometer. The data were accumulated in 144 four-dimensional bins of Q2, xB, −t and ϕ over a wide kinematic range, where ϕ is the azimuthal angle between the lepton and hadron scattering planes, The measured azimuthal dependence with large amplitudes of the sinϕ moments is a clear indication of a substantial contribution to the polarized cross-section from transversely polarized virtual photons. In the framework of generalized parton distributions (GPDs) this contribution is expressed via longitudinal-transverse interference between chiral-even and chiral-odd GPDs. The experimental results are compared to the existing theoretical models demonstrating the sensitivity to the product of chiral-odd and chiral-even GPDs and provide new constraints to the existing GPD parameterizations.
Zhao, B.; Kim, A.; Joo, K.; Bedlinskiy, I.; Kim, W.; Kubarovsky, V.; Ungaro, M.; Adhikari, S.; Akbar, Z.; Angelini, G.; Avakian, H.; Ball, J.; Baltzell, N. A.; Barion, L.; Bashkanov, M.; Battaglieri, M.; Batourine, V.; Biselli, A. S.; Boiarinov, S.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chatagnon, P.; Chetry, T.; and Hicks, K., "Measurement of the beam spin asymmetry of e→p→e′p′η in the deep-inelastic regime with CLAS" (2019). Physics & Astronomy Open Access Publications. 45.