Absence of spin dependence in the final state interaction of the d(pol) p --> 3He eta reaction

TL;DR

The study measures the deuteron tensor analyzing power in the d(pol) p --> 3He eta reaction near threshold, finding no spin dependence in the final state interaction despite large amplitude variations.

Contribution

It provides new experimental evidence that the final state interaction in this reaction is not affected by the initial spin configuration.

Findings

t_{20} shows little energy dependence despite amplitude variation

Final state interaction is not influenced by initial spin configuration

Weak angular dependence offers insights into near-threshold amplitude structure

Abstract

The deuteron tensor analysing power t_{20} of the d(pol) p --> 3He eta reaction has been measured at the COSY-ANKE facility in small steps in excess energy Q up to Q = 11 MeV. Despite the square of the production amplitude varying by over a factor of five through this range, t_{20} shows little or no energy dependence. This is evidence that the final state interaction causing the energy variation is not influenced by the spin configuration in the entrance channel. The weak angular dependence observed for t_{20} provides useful insight into the amplitude structure near threshold.