Excitation of the isobar in deuteron charge exchange on hydrogen at 1.6, 1.8, and 2.3 GeV

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• 作者：D. Mchedlishvili ; S. Barsov ; J. Carbonell ; D. Chiladze ; S. Dymov ; A. Dzyuba ; R. Engels ; R. Gebel ; V. Glagolev ; K. Grigoryev ; P. Goslawski ; M. Hartmann ; O. Imambekov ; A. Kacharava ; V. Kamerdzhiev ; I. Keshelashvili ; A. Khoukaz ; V. Komarov ; P. Kulessa ; A. Kulikov ; et al.
• 关键词：Deuteron charge exchange ; Pion production ; Polarisation effects
• 刊名：Physics Letters B
• 出版年：2013
• 出版时间：7 October, 2013
• 年：2013
• 卷：726
• 期：1-3
• 页码：145-150
• 全文大小：302 K

文摘

The charge-exchange break-up of polarised deuterons , where the final diproton system has a very low excitation energy and hence is mainly in the state, is a powerful tool to probe the spin-flip terms in the proton-neutron charge-exchange scattering. Recent measurements with the ANKE spectrometer at the COSY storage ring at 1.6, 1.8, and 2.27 GeV have extended these studies into the pion-production regime in order to investigate the mechanism for the excitation of the isobar in the reaction. Values of the differential cross section and two deuteron tensor analysing powers, and , have been extracted as functions of the momentum transfer to the diproton or the invariant mass of the unobserved system X. The unpolarised cross section in the high region is well described in a model that includes only direct excitation of the ¦¤ isobar through undistorted one pion exchange. However, the cross section is grossly underestimated for low , even when ¦¤ excitation in the projectile deuteron is included in the calculation. Furthermore, direct ¦¤ production through one pion exchange only reproduces the angular dependence of the difference between the two tensor analysing powers.