Total and differential cross sections of $eta$-production in proton-deuteron fusion for excess energies between $Q_eta=13;text{MeV}$ and $Q_eta=81;text{MeV}$

New data on both total and differential cross sections of the production of $eta$ mesons in proton-deuteron fusion to ${}^3text{He},eta$ in the excess energy region $13.6;text{MeV}leq Q_eta leq 80.9;text{MeV}$ are presented. These data have been obtained with the WASA-at-COSY detector setup located at the Forschungszentrum Julich, using a proton beam at 15 different beam momenta between $p_p = 1.60;text{GeV}/c$ and $p_p = 1.74;text{GeV}/c$. While significant structure of the total cross section is observed in the energy region $20;text{MeV}lesssim Q_eta lesssim 60;text{MeV}$, a previously reported sharp variation around $Q_etaapprox 50;text{MeV}$ cannot be confirmed. Angular distributions show the typical forward-peaking that was reported elsewhere. For the first time, it is possible to study the development of these angular distributions with rising excess energy over a large interval.