First measurement of polarisation transfer Cx′n in deuteron photodisintegration

Abstract

A first measurement of the polarisation transfer from a circularly-polarised photon to the final state neutron (Cx′n) in deuterium photodisintegration has been carried out. This quantity is determined over the photon energy range 370 – 700 MeV and for neutron centre-of-mass breakup angles ∼45−120∘. The polarisation of the final state neutrons was determined by an ancillary large-acceptance nucleon polarimeter, surrounding a cryogenic liquid deuterium target within the Crystal Ball detector at MAMI. The polarimeter characterised (n,p) charge exchange of the ejected neutrons to determine their polarisation. The new Cx′n data are also compared to a theoretical model based on nucleonic and nucleon resonance degrees of freedom constrained by the current world-database of deuterium photodisintegration measurements. Structures in Cx′n observed in the region of the d⁎(2380) could not be explained by conventional models of deuteron photodisintegration.

Metadata

Funding Information: We are indebted to M. Zurek for providing us data on C analysing powers. All data are available for downloading from PURE [40] . This work has been supported by the U.K. STFC ( ST/V002570/1 , ST/L00478X/2 , ST/V001035/1 , ST/P004385/2 , ST/T002077/1 , ST/L005824/1 , 57071/1 , 50727/1 ) grants, the Deutsche Forschungsgemeinschaft ( SFB443 , SFB/TR16 , and SFB1044 ), DFG-RFBR (Grant No. 09-02-91330 ), Schweizerischer Nationalfonds (Contracts No. 200020-175807 , No. 200020-156983 , No. 132799 , No. 121781 , No. 117601 ), the U.S. Department of Energy (Offices of Science and Nuclear Physics, Awards No. DE-SC0014323 , DEFG02-99-ER41110 , No. DE-FG02-88ER40415 , No. DEFG02-01-ER41194 ) and National Science Foundation (Grants NSF OISE-1358175 ; PHY-1039130 , PHY-1714833 , No. IIA-1358175 ), INFN (Italy), and NSERC of Canada (Grant No. FRN-SAPPJ2015-00023 ). Publisher Copyright: © 2023 The Authors

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