Quasi-Bound ³He − η State and Spin-Observables of the Reaction pd → ³Heη

Joint Institute for Nuclear Research, Moscow reg. Dubna, Joliot Curie, 6, 141980 Russia

^a e-mail: uzikov@nusun.jinr.ru

Abstract

A formalism for total set of spin observables of the reaction pd → ³Heη derived in a model independent way is presented and a possibility to perform a complete polarization experiment is investigated. Separation of s- and p-wave amplitudes of this reaction in the threshold region allows one to determine a position of the quasibound pole in the ³He − η system. It is shown that in order to get such a separation one should measure spin-transfer coefficients in addition to analyzing powers and spin-correlations. Specific observables, given by products of one s- and one p-wave amplitudes, are found. Measurement of these observables will provide new independent information on the ³He − η pole position and this allows one to determine whether the ³He − η state is quasi-bound or anti-bound.