New data on both total and differential cross sections of the production of η mesons in proton–deuteron fusion to He3η in the excess energy region 13.6MeV≤Q η ≤80.9MeV are presented. These data have been obtained with the WASA-at-COSY detector setup located at the Forschungszentrum Jülich, using a proton beam at 15 different beam momenta between p p =1.60GeV/c and p p =1.74GeV/c. While significant structure of the total cross section is observed in the energy region 20MeV≲Q η ≲60MeV, a previously reported sharp variation around Q η ≈50MeV cannot be confirmed. Angular distributions show the typical forward-peaking that was noted earlier. For the first time, it is possible to study the development of these angular distributions with rising excess energy over a wide interval.
Adlarson, P., Augustyniak, W., Bardan, W., Bashkanov, M., Bergmann, F. S., Berłowski, M., … Wilkin, C. (2018). Total and differential cross sections of η-production in proton–deuteron fusion for excess energies between Q η = 13 MeV and Q η = 81 MeV. Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 782, 297–304. https://doi.org/10.1016/j.physletb.2018.05.036