Total and differential cross sections of $\hat{I}\cdot$-production in proton-deuteron fusion for excess energies between $Q_{\hat{I}}\cdot =13\text{MeV}$ and $Q_{\hat{I}}\cdot =81\text{MeV}$

Abstract

New data on both total and differential cross sections of the production of $\hat{I}\cdot$ mesons in proton-deuteron fusion to ${}^3\text{He}\hat{I}\cdot$ in the excess energy region $13.6\text{MeV}\le Q_{\hat{I}}\cdot \le 80.9\text{MeV}$ 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 $p_p=1.60\text{GeV}/c$ and $p_p=1.74\text{GeV}/c$. While significant structure of the total cross section is observed in the energy region $20\text{MeV}\lesssim Q_{\hat{I}}\cdot \lesssim 60\text{MeV}$, a previously reported sharp variation around $Q_{\hat{I}}\cdot \approx 50\text{MeV}$ 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.

8 pages, 7 figures, preprint submitted to Physics Letters B