Precision study of the d+p->3He+eta reaction for excess energies between 20 and 60 MeV

TL;DR

This study measures the cross sections of the d+p->3He+eta reaction at various energies, revealing the evolution of partial wave contributions and providing high-precision data that enhance understanding of eta production mechanisms.

Contribution

It provides high-precision differential and total cross section data over a range of energies, improving upon previous measurements and analyzing partial wave contributions in eta production.

Findings

Data agree with previous trends and higher-precision measurements.

At 19.5 MeV, s- and p-wave production describe the results.

At 59.4 MeV, higher partial waves are necessary.

Abstract

The differential and total cross sections for the d+p->3He+eta reaction have been measured at COSY-ANKE at excess energies of 19.5, 39.4, and 59.4 MeV over the full angular range. The results are in line with trends apparent from the detailed near-threshold studies and also agree with those from CELSIUS, though the present data have higher precision. While at 19.5 MeV the results can be described in terms of s- and p-wave production, by 59.4 MeV higher partial waves are required. Including the 19.5 MeV point together with the near-threshold data in a global s- and p-wave fit gives a poorer overall description of the data though the position of the pole in the 3He scattering amplitude, corresponding to the quasi-bound or virtual state, is hardly changed.