%0 Electronic Article
%A Adlarson, P.
%A Augustyniak, W.
%A Bardan, W.
%A Bashkanov, M.
%A Bergmann, F. S.
%A Berłowski, M.
%A Bondar, A.
%A Büscher, M.
%A Calén, H.
%A Ciepał, I.
%A Clement, H.
%A Czerwiński, E.
%A Demmich, K.
%A Engels, Ralf W.
%A Erven, A.
%A Erven, W.
%A Eyrich, W.
%A Fedorets, P.
%A Föhl, K.
%A Fransson, K.
%A Goldenbaum, F.
%A Goswami, A.
%A Grigoryev, K.
%A Gullström, C. -O.
%A Hanhart, C.
%A Heijkenskjöld, L.
%A Hejny, V.
%A Hüsken, N.
%A Jarczyk, L.
%A Johansson, T.
%A Kamys, B.
%A Kemmerling, G.
%A Khatri, G.
%A Khoukaz, A.
%A Khreptak, O.
%A Kirillov, D. A.
%A Kistryn, S.
%A Kleines, H.
%A Kłos, B.
%A Krzemień, W.
%A Kulessa, P.
%A Kupść, A.
%A Kuzmin, A.
%A Lalwani, K.
%A Lersch, D.
%A Lorentz, B.
%A Magiera, A.
%A Maier, R.
%A Marciniewski, P.
%A Mariański, B.
%A Morsch, H. -P.
%A Moskal, P.
%A Ohm, H.
%A Parol, W.
%A del Rio, E. Perez
%A Piskunov, N. M.
%A Prasuhn, D.
%A Pszczel, D.
%A Pysz, K.
%A Pyszniak, A.
%A Ritman, J.
%A Roy, A.
%A Rudy, Z.
%A Rundel, O.
%A Sawant, S.
%A Schadmand, S.
%A Schätti-Ozerianska, I.
%A Sefzick, T.
%A Serdyuk, V.
%A Shwartz, B.
%A Sitterberg, K.
%A Skorodko, T.
%A Skurzok, M.
%A Smyrski, J.
%A Sopov, V.
%A Stassen, R.
%A Stepaniak, J.
%A Stephan, E.
%A Sterzenbach, G.
%A Stockhorst, H.
%A Stroeher, Hans
%A Szczurek, A.
%A Trzciński, A.
%A Wolke, M.
%A Wrońska, A.
%A Wüstner, P.
%A Yamamoto, A.
%A Zabierowski, J.
%A Zieliński, M. J.
%A Złomańczuk, J.
%A Żuprański, P.
%A Zurek, Maria
%T Importance of d-wave contributions in the charge symmetry breaking reaction $dd \to {}^4\text{He}\pi^0$
%M FZJ-2017-06364
%D 2017
%Z 3 figures
%X This letter reports the first measurement of the contribution of higher partial waves in the charge symmetry breaking reaction $dd \to {}^4\text{He}\pi^0$ using the WASA-at-COSY detector setup at an excess energy of $Q = 60$ MeV. The determined differential cross section can be parametrized as $\text{d}\sigma/\text{d}\Omega = a + b\cos^{2}\theta^*$, where $\theta^*$ is the production angle of the pion in the center-of-mass coordinate system, and the results for the parameters are $a = \left(1.55 \pm 0.46 (\text{stat}) ^{+0.32}_{-0.8} (\text{syst}) \right) \text{pb/sr}$ and $b = \left(13.1 \pm 2.1 (\text{stat}) ^{+1.0}_{-2.7} (\text{syst})\right) \text{pb/sr}$. The data are compatible with vanishing $p$-waves and a sizable $d$-wave contribution. This finding should strongly constrain the contribution of the $\Delta$ isobar to the $dd \to {}^4\text{He}\pi^0$ reaction and is therefore crucial for a quantitative understanding of quark mass effects in nuclear production reactions.
%F PUB:(DE-HGF)25
%9 Preprint
%U https://juser.fz-juelich.de/record/837451